# How far are we from colonizing off Earth?



## Bullgrit (Aug 9, 2010)

Realistically, how many years are we away from colonizing:

The Moon

Mars

Any planet outside the Solar System

Bullgrit


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## Man in the Funny Hat (Aug 9, 2010)

Bullgrit said:


> Realistically, how many years are we away from colonizing:
> 
> The Moon



We could do it right now.  There just isn't enough money or anticipated benefit to science to justify it.



> Mars



The moon is "easily" kept supplied from Earth compared to Mars.  A Mars colony really sort of needs to be self-contained, self-reliant.  This becomes MUCH easier when a reliable source of water can be identified.  Assuming that can be found, and again that the money and/or scientific benefit limitations are also overcome, I'd say 20 years (?) from today before plans could be finalized and committed to, then another 20 before it's actually on its feet.



> Any planet outside the Solar System



Absolutely indeterminate.  Short of purely fictional science and Star Trek levels of global peace and prosperity for the project, interstellar distances are functionally impractical for humanity to bridge with a colonization effort.  It's strictly a theoretical possibility.  May as well pick a date out of a hat - and then the technology available will likely make current technology seem literally stone-age.


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## Ed_Laprade (Aug 9, 2010)

10 years. Everything that is 'going to happen' sometime in the future is always 'just 10 years away'. Flying cars anyone? (Ok, technically they exist, but when will the average driver be able to get one? In 10 years, of course!)


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## Joker (Aug 9, 2010)

Yeah, until there's some kind of economic benefit or need to colonize I don't see it happening any time soon.

If a Mars probe found a valuable material you could have governments up there in no time.

As an aside.  Is buying land on the Moon actually recognized as your property?


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## hafrogman (Aug 9, 2010)

Bullgrit said:


> Realistically, how many years are we away from colonizing:



Realistically is the key problem here.







Man in the Funny Hat said:


> We could do it right now.  There just isn't enough money or anticipated benefit to science to justify it.



As the Man pointed out, the trick is motivation.

To get people to colonize, there has to be a resource crunch, to drive people to the lengths required.  From a "when WILL we do it" standpoint (as opposed to a "when CAN we do it" view) I'd say any space colonization is very far off, barring special circumstances.

Food and water crunches are the most likely resource competition the future will bring.  Neither of these is really helped by the Moon or Mars.  You're far more likely to see something like a floating or underwater city with desalination plants and hydroponics labs to address these needs.

A land crunch is unlikely because food and water will limit population first.  But if you somehow solve those limits, the population could probably double every 60 years.  So maybe 120 years is the point at which overcrowding drives moon colonization over oceanic colonies.

Other resources would need to be something valuable to export.  As far as I know, the Moon is pretty much silicate (worthless) all the way down.  Mars could presumably have some special mineral deposits, but to overcome shipping costs it'd have to be far more valuable than gold or diamonds.  It'd need to be something useful that we have either run out of, or don't have and can't make.  Like Unobtanium rare.

The final driving factor is something happening on Earth to reduce what we have.  Global climate change, volcanic eruption, meteor strike, nuclear fallout, take your pick.  Something to make those that can afford it take flight to live in peace on the Moon.  As the Man said, it can be done now.  So, whenever you think one of these is likely (tomorrow to 1,000 years).


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## jonesy (Aug 9, 2010)

We have the technology. We could do it tomorrow. The guys are right. All that's missing from the equation is motivation.

Nuclear torch rockets easily get all the mass of all the equipment we'd need into orbit, and to other planets. 99% of the power needed for spacetravel is used up in getting off a gravity well and landing on one. The travel only takes time. Protection against radiation and micrometeorites is easy if you have a big enough mass of materials to build a properly shielded ship. Just stack water containers and hard substances into a layered bunker-like container. Building shelters on Mars is, once again, easy if you bring enough materials along. The hard part is getting plants to grow on Mars greenhouses, and the biggest hurdle is creating a sustainable life cycle.

But you did say colonizing. Now terraforming, that is really really hard. =)


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## Theo R Cwithin (Aug 10, 2010)

Back in 1992 or so I heard a talk given by Dr. Hans Mark, former deputy director of NASA.  He said if we started immediately at that time we could land a man on Mars in 2017.  In other words, 25 years from the time the program is committed just to land a man on Mars-- not actually colonize it.  Note that at this point in time, we're retiring the Space Shuttle (1970's technology), and have no replacement for it.

I'm not optimistic.  My guess: 30 years, minimum, for the Moon, 60 years, minimum, for Mars.


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## jonesy (Aug 10, 2010)

the_orc_within said:


> ...My guess: 30 years, minimum, for the Moon...



I don't think we'll ever colonize the Moon. There will never be a reason for it. There's stuff we could mine, like Helium 3 (if it's actually abundant there, and if we can ever actually get fusion to work so we can use it for it), but we don't need to colonize it for that. Robots controlled from orbit, or better yet Earth, are more likely.

Some people say that the Moon is a good stepping stone to the stars. No. It's not. The orbit is a good stepping stone. The only good stepping stone, actually. The best stepping stone would be a refuelling station in orbit of Jupiter, or something along those lines. If we could ever build a well enough shielded station which could withstand Jovian radiation, where shielded means massive enough.


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## Umbran (Aug 10, 2010)

jonesy said:


> We have the technology. We could do it tomorrow.




That is not exactly true.  We can design and build appropriate rockets, but are not in possession of them this instant.  Tomorrow, or next year, would not be an option, as designing and building "heavy-lift" capacity is not like designing and building a new car.  The (now canceled) Constellation program was intending to use current known principles (chemical rockets), but largely new designs.  They planned to start tech development in 2005, with first manned flight in 2014.  First flight to the Moon was set for 2019.  So, we're talking 9 to 14 years using largely known technologies.  Call it a round decade.

Now, with a whole lot of money, and a less conservative idea of what counts as "acceptable risk", you can do this sort of thing in less than nine years - but doing that you may also end up with dead astronauts and wasting a lot of money on an abject failure.



> Nuclear torch rockets easily get all the mass of all the equipment we'd need into orbit, and to other planets.




Unless you want to spray a whole lot of fallout on living people, there is no known nuclear option that you can use to get into orbit.  Nuclear options are good for use outside the atmosphere, not within it, and are better for low-thrust (long distance) travel, rather than boosting off a planetary surface.



> Protection against radiation and micrometeorites is easy if you have a big enough mass of materials to build a properly shielded ship.




Well, to go to the Moon, you don't need a whole lot of shielding.  

To go to Mars, you need that shielding.  But, while simple in concept, it is expensive in practice.  Unless you first build a Moon station that can produce it, every single ounce of your shielding has to come from the surface of the Earth.  That is expensive.


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## Umbran (Aug 10, 2010)

jonesy said:


> I don't think we'll ever colonize the Moon. There will never be a reason for it.




See what I said above about shielding.  If you are trying to get heavy masses to the rest of the solar system, it takes a whole lot less oomph to get it there from the Moon than the Earth's surface.  At that point you're talking about production facilities on the Moon.  They can be heavily automated, but you'd still need people present to deal with breakdowns.


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## jonesy (Aug 10, 2010)

Umbran said:


> Unless you want to spray a whole lot of fallout on living people, there is no known nuclear option that you can use to get into orbit.



Fair point. Unless you found a place on Earth where that wasn't an issue.

Or, you could use a Verne Gun:
The Verne Gun — KarlSchroeder.com



> That is expensive.



Yes. Which goes straight into the idea of needing motivation. If we had it, the cost wouldn't matter. Since we don't, the cost is everything.



> See what I said above about shielding.  If you are trying to get heavy masses to the rest of the solar system, it takes a whole lot less oomph to get it there from the Moon than the Earth's surface.  At that point you're talking about production facilities on the Moon.  They can be heavily automated, but you'd still need people present to deal with breakdowns.



I get what you're saying, but I think moondust alone is reason enough to keep the production line in orbit.


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## surfarcher (Aug 10, 2010)

I think we are close. Real close.

Just a few short millenia left... Just a few heartbeats in cosmic terms.

LMAO!


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## Banshee16 (Aug 10, 2010)

Bullgrit said:


> Realistically, how many years are we away from colonizing:
> 
> The Moon
> 
> ...




According to a special on National Geographic a few weeks back, Mars at least will be a while.

Now, it depends on what you mean by colonizing.  If you mean landing people there, then probably within 5-10 years.  But if you're talking about longterm habitation, quite a bit longer.  Unless they've got huge buildings with greenhouses and ways of growing food and replenishing water, it could be centuries.  Terraforming could take 800 years.

I'm not sure that I count having a land-based capsule or research lab where scientists live for 6 months, then come back to earth as "colonizing".

As to getting beyond the solar system, I don't think it's realistic.  I think if they ever get to the point that they get behind public unwillingness to have nuclear power being used in space, it's unlikely to ever happen.  Though I do remember something about Canadian scientists creating an ion drive or something like that....which would multiple space travel times by a factor of 10x or something like that.  Taking 6 weeks to get to Mars, instead of 6 months would make it a lot more feasible.

Banshee


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## Banshee16 (Aug 10, 2010)

Umbran said:


> Unless you want to spray a whole lot of fallout on living people, there is no known nuclear option that you can use to get into orbit.  Nuclear options are good for use outside the atmosphere, not within it, and are better for low-thrust (long distance) travel, rather than boosting off a planetary surface.




So, you use more conventional rockets to get from Earth to an orbital "bus stop" and then use a nuclear powered craft that leaves earth, and heads for other planets.

Realistically, I think we'd need major, major scientific advances before we could ever get out of our solar system.  With the nearest solar system being....what.....60 million light years away, and no craft or technology capable of getting anywhere near light speed, it could take centuries or millenia to reach the next star.

Call me a cynic, but I don't think we have that long.  I figure we'll wipe ourselves out within a few centuries anyways.

Of course, what do I know....my background is psychology, not astrophysics or engineering 

Banshee


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## Umbran (Aug 10, 2010)

Banshee16 said:


> So, you use more conventional rockets to get from Earth to an orbital "bus stop" and then use a nuclear powered craft that leaves earth, and heads for other planets.




Yep.  Probably ion engines run off a small nuclear power plant.



> With the nearest solar system being....what.....60 million light years away...




Um, no.  The entire galaxy is only 100,000 light years in diameter.  The nearest star is 4.37 light years (about 26 trillion miles) away



> ...and no craft or technology capable of getting anywhere near light speed, it could take centuries or millenia to reach the next star.




If we can get a craft up to 10% of lightspeed, it'd take about 60 or 70 years to reach the nearest star.  The nearest known planet outside the solar system is somewhat more distant (about 10 light years away).


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## jonesy (Aug 10, 2010)

Banshee16 said:


> With the nearest solar system being....what.....60 million light years away, and no craft or technology capable of getting anywhere near light speed, it could take centuries or millenia to reach the next star.



60 million lightyears? There must be a unit conversion error there somewhere. I'm just having trouble deciding which one it might be. 

But with the distances involved it hardly matters.

The closest star is Proxima Centauri at 4.2 lightyears. That's about 40 trillion kilometers.

The closest detected exoplanet (planet orbiting a star other than Sol) orbits Epsilon Eridani, which is 10.5 lightyears away (63 trillion miles). Most of the others (that we've detected) are within 300 lightyears of us.

What's 60 million lightyears away? the spiral galaxy called Messier 90.

The fastest theoretically viable stardrive at the moment seems to be nuclear pulse propulsion (correct me if you find something faster, please). The Project Orion. It would get you to Proxima Centauri in 85 years. If you used the Ion drive we now have working, 8000 years. Yeah.

Edit: sorry, now I made an error: the ion drive would get you to Proxima Centauri in 80000 years.


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## Orius (Aug 10, 2010)

Probably about 100 years or so to colonize within the solar system.

Outside, it depends on what if any kinds of FTL or near-FTL flight we can develop.  FTL is currently beyond our technology if even possible.   

The biggest hurdles though aren't technological but political, unfortunately.  There are always those who think space is just a waste of time and are content to just sit around on the Earth and worry about poverty and the environment until the Sun gets big enough to burn the oceans and atmosphere away.  No amount of money or green thinking will save the biosphere when that happens.


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## RangerWickett (Aug 10, 2010)

I figure within 50 years we'll have telescopes precise enough to have located a habitable planet somewhere. Some cadre of super-rich folks will decide to invest billions of dollars to launch a ship there, but it won't have a living person. It will have a very advanced artificial intelligence, and a variety of ultralight robots capable of exploring once it lands. 

20 years later they'll actually get around to launching the thing.

A hundred years after that, the ship might be a tenth of the way to its destination when some stupid mistake here on earth completely obliterates the ability to keep in contact with it. 

Somewhere close to the 31st century, radio signals will reach earth from this planet. People will flip the f*** out, because everyone will have forgotten about the ship, so they'll assume it's an alien intelligence.


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## Dire Bare (Aug 10, 2010)

Orius said:


> There are always those who think space is just a waste of time and are content to just sit around on the Earth and worry about poverty and the environment until the Sun gets big enough to burn the oceans and atmosphere away.  No amount of money or green thinking will save the biosphere when that happens.




Ah, the sun expanding and destroying the Earth's capacity to support life is a loooooooonnnngggg time away . . . we're not even talking geologic timescales, but cosmologic!

Even if we rolled back our impending climate changes to pre-industrial levels tomorrow, the human race will likely no longer exist before we have to start worrying about the sun expanding . . .

And at the rate our activities are changing our climate, it's a much more immediate and realistic concern.


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## Hand of Evil (Aug 10, 2010)

I do not see it in the next 100 years - yes we could do it and yes there is enough reasons to do it (the moon with H3) but we just lack the vision and drive.  There is no "race" for what is there and limited resources being applied for better means to get there.  

Add to that the growing issues of population and climate change, our focus will be earth bound for a very long time.


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## Merkuri (Aug 10, 2010)

Regarding colonizing exoplanets, Voyager I was launched in the 70s, and it's just barely breached the edge of our solar system.  Our long-scale transportation technology hasn't improved much since then.  At least, we're still nowhere near other star systems.

I think sci-fi shows like Star Trek have spoiled a lot of us into not realizing how huge our own solar system is.  Carl Sagan sums it up best in his comments about the Pale Blue Dot photo taken by Voyager I.  Voyager had turned its camera around and taken a picture of Earth from the edges of the solar system, and our planet was just a single pixel.  To quote Sagan:



> From this distant vantage point, the Earth might not seem of particular interest. But for us, it's different. Consider again that dot. That's here, that's home, that's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.




Before we go colonizing other planets, not only do we need to greatly advance our travel technology, but we need to _find_ those other planets.  I believe someone earlier in the thread said that the nearest known exoplanet was orbiting Epsilon Eridani, but I'm pretty sure that this planet is a gas giant, not suited for humans to land on (never mind live on).  In fact, just about every exoplanet we've found so far is a gas giant.  I don't think we have the technology yet to detect tiny earth-like planets.

So not only do we need to find a way to get to exoplanets, we need to find them first.  We're a very long way away from that unless there are a couple of _major_ scientific breakthroughs in the next few years.


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## Plane Sailing (Aug 10, 2010)

jonesy said:


> The Project Orion. It would get you to Proxima Centauri in 85 years.




Is that in "objective" time1 from the point of view of the observer on earth, or subjective time1 from the point of view of the astronauts on board the Orion?

Time dilation due to special relativity makes it somewhat less boring for the travellers if you get fast enough.



1. Yes, I know it is all subjective to the frame of reference, but I hope that phrasing it this way might make the question more generally intelligible


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## El Mahdi (Aug 10, 2010)

*How far are we from colonizing off Earth?*

Well, on average, about 240,000 miles from the Moon and varies between 35 million and 250 million miles for Mars...




Okay, all kidding aside...

For the last few years it looked like we were maybe about 10 or 15 years from "colonizing" the Moon, and maybe as little as 30 years from "colonizing" Mars - but then the Constellation program was cancelled...

We have the technology to be able to do it (or at least the ability to _develop_ the technology), but like others are saying, we don't seem to have the motivation.

Right now, it looks like the leading impetus for any type of colonization on the moon might be commercial tourism.  As for official research and exploration type colonization, it seems to be on permanent high-speed hold.  Until the world's economies significantly improve, I just don't see it happening.  Perhaps it won't happen at all until population pressure and resource shortages make it necessary? It could even be the next century before it happens...


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## Pbartender (Aug 10, 2010)

Technically, we have the know-how to colonize the local solar system now, though as Umbran said, it would take a few years at the least to build the necessary equipment to do it with.

The problem is that, as others have said, there's no good reason to do it, other than to say we we did it.

It's going to be a long, long time before shipping exploitable resources in from other planets becomes cheaper than trying to squeeze more out of the Earth.  At this point, it's a far better use of our time to advance reclamation and recycling technology, than off-world mining technology.

And as far as population concerns go...  How many people do expect to ship off-world?  The world-wide population growth is something like 75 million people a year.  Right now, we can put about a half dozen people into orbit at a time.

So, while it feasible that it could be done, there's no real terribly good reason to do it, other than for exploration's sake.


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## jonesy (Aug 10, 2010)

Plane Sailing said:


> Is that in "objective" time1 from the point of view of the observer on earth, or subjective time1 from the point of view of the astronauts on board the Orion?



I took the most optimistic estimate of the Orions speed, which is 5% of the speed of light. At that speed 1 day for crew equals 1.001252 days for Earth. 85 years for the crew is then 85.1 years for Earth.

Edit: one needs to remember that the Orions speeds are all rough estimates. One of the reasons why it's so slow (hah!) is that it's not a linear speed. The Orion works by repeatedly accelerating itself with repeated nuclear detonations. It takes time to reach certain speeds. Nobody knows what the actual top speed would have been because the tests were cancelled because of the nuclear test ban treaties in the 60's.


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## Umbran (Aug 10, 2010)

jonesy said:


> The fastest theoretically viable stardrive at the moment seems to be nuclear pulse propulsion (correct me if you find something faster, please). The Project Orion. It would get you to Proxima Centauri in 85 years. If you used the Ion drive we now have working, 8000 years. Yeah.




One small note: you're comparing a drive system that is theoretical (a nuclear pulse drive that we've never built) to something that currently exists (the ion drive we have now).  Type mismatch.

The next generation of ion drives that are being tested produce thrust 10 to 100 times greater than the current ion drives we've actually used on missions.  They are not, as I understand it, near the theoretical maximum.


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## jonesy (Aug 10, 2010)

Umbran said:


> One small note: you're comparing a drive system that is theoretical (a nuclear pulse drive that we've never built) to something that currently exists (the ion drive we have now).  Type mismatch.



Yup.



> The next generation of ion drives that are being tested produce thrust 10 to 100 times greater than the current ion drives we've actually used on missions.  They are not, as I understand it, near the theoretical maximum.



80000/100 = 800 years. I hope the theoretical max of those is a lot better.

By the way, there is something theoretical that is actually faster than the Orion. Remember the cool ship at the beginning of Avatar? That's actually based on the Valkyrie antimatter propulsion model. It could get you to 92% lightspeed. Guess what the downside is? Antimatter is expensive enough to bankrupt the entire planet several times over.


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## jonesy (Aug 10, 2010)

Oh, and if you're wondering about relativity at 92% lightspeed: 1 day for crew would be 2.551552 days for Earth. Still not that bad, but after that point the ratio is going to start going up pretty darn fast. When you get past 98% even fractions of fractions will add weeks to the difference.


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## TanisFrey (Aug 10, 2010)

Joker said:


> Yeah, until there's some kind of economic benefit or need to colonize I don't see it happening any time soon.
> 
> If a Mars probe found a valuable material you could have governments up there in no time.
> 
> As an aside.  Is buying land on the Moon actually recognized as your property?



There is an international treaty preventing any nation from claiming any portion of the lunar surface as part of their territory.  (I think that it extended to other portions of the solar system also)  This pretty well kills anyone ability to buying land on the moon.


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## hafrogman (Aug 10, 2010)

TanisFrey said:


> There is an international treaty preventing any nation from claiming any portion of the lunar surface as part of their territory.  (I think that it extended to other portions of the solar system also)  This pretty well kills anyone ability to buying land on the moon.



Or you land there and declare independance as a sovereign nation, unconstrained by treaties you're not a signatory body to.  Of course, this leaves all the other nations of the planet free to invade you ... but given the prohibitive cost of getting bullets, guns, soldiers and tanks to the moon ... you could be pretty safe.


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## Pbartender (Aug 10, 2010)

jonesy said:


> Yup.
> 
> 
> 80000/100 = 800 years. I hope the theoretical max of those is a lot better.
> ...




It's not the cost of antimatter that's prohibitive, but the time it takes to produce it in any quantity and the ability to effectively store it for any length of time.

The last time I checked, our best antimatter "factory" can't produce much more than about a billionth of a spoonful of antimatter in a year, and it doesn't even have the capacity store all of that at once, much less ship it anywhere useful.  The storage facility -- for round about a hundred-billionth of a gram, mind you -- is a ring a half kilometer in circumference and made of electromagnets the size of small cars.

Considering that a typical one-month trip to Mars would require roughly 10 grams or so (a third of an ounce) of antimatter, I don't think antimatter propulsion will viable any time in the near future without some truly amazing breakthroughs in high-energy physics technology.  It hard to say how soon it could happen, but I wouldn't bet money on it.


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## jonesy (Aug 10, 2010)

Pbartender said:


> The storage facility -- for round about a hundred-billionth of a gram, mind you -- is a ring a half kilometer in circumference and made of electromagnets the size of small cars.



Yikes. Does that scale accordingly? If you need a bigger lump of the stuff, do you also need a bigger ring and magnets?


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## coyote6 (Aug 10, 2010)

Charles Stross has had some interesting blog posts on this subject; here's one. He does not seem to think it's terrifically feasible, barring some impossible-to-predict technological inventions. He points out the many areas of Earth that are uninhabited, yet far more inhabitable than Mars or the like.


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## catsclaw227 (Aug 10, 2010)

According to Stephen Hawking, in a recent article on Kurzweilai.net, we best be getting out butts moving on this otherwise we'll just burn out the planet we are on.

Stephen Hawking’s Warning: Abandon Earth—Or Face Extinction | KurzweilAI


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## Pbartender (Aug 10, 2010)

catsclaw227 said:


> According to Stephen Hawking, in a recent article on Kurzweilai.net, we best be getting out butts moving on this otherwise we'll just burn out the planet we are on.
> 
> Stephen Hawking’s Warning: Abandon Earthâ€”Or Face Extinction | KurzweilAI




As smart as he is, there's a fundamental flaw in Hawking's argument, however...

As Coyote6 says, barring some impossible-to-predict technological inventions, there's no way that extraterrestrial colonization is going to make the slightest dent in either our population problem or our resource consumption problem.  We just can't feasibly ship people out fast enough, and we can't ship resources in fast enough to make any appreciable difference.

All we could hope for is to establish a sort of off-world "Noah's Ark" so that human society and earth ecology can continue should some catastrophe befall Earth...  At best, it'd prevent all of our eggs from sitting in one planetary basket.

And that is one of the main arguments against extraterrestrial colonization...  That the resources, manpower and money for manned space exploration and colonization would be far better spent putting our own proverbial house in order, instead of moving into a new one and trashing that one too.


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## TwinBahamut (Aug 11, 2010)

All told, there are just two things we need to done in order to put people _anywhere_ in the solar system. First, we need a better way to put people and equipment into space than the traditional space shuttle system. Second, we need to put enough people and equipment into space in order to build a large permanent habitat in space capable of housing a few thousand people, processing materials, and manufacturing goods on its own. Once we have that, the solar system would be our playground.

With a single working orbital colony, strip-mining the moon for raw materials is ridiculously efficient compared to hauling stuff up from the Earth, so it becomes easy to build bigger and better orbital colonies. And once you have permanent space habitats, taking the long, energy efficient route to other planets in the solar system is a lot more feasible (certainly more feasible than launching a ship built on Earth directly to Mars), because even if it takes years to get anywhere you could still do so comfortably (and bring the whole family along for the ride). The first colonization of Mars probably won't be a couple dozen astronauts riding a shuttle launched from Earth's surface, it will probably be when a few large-scale permanent space colonies each filled with millions of people arrive into orbit around the planet.

Anyways, according to the people who first really looked into these possibilities, we could have had that critical, first permanent orbital colony by the mid nineties or so. So the question is not so much "How far are they away?" but rather "For what reasons have we not done so already?"

As for travel to worlds outside of the solar system... Honestly, I don't have a clue. I don't think identification of habitable Earth-like planets is at all necessary, since man-made structures placed near large gas-giants or in stable orbits of stars themselves would be perfectly suitable for human habitation. Nor do I think it would be strictly necessary to bring significant sub-light speeds into the equation, since people may very well be willing to set out on journeys that would not be completed in their own lifetimes. It probably won't happen until the solar system as whole becomes crowded, though, which may take centuries or even millenia from the time the colonization of the solar system begins.


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## Banshee16 (Aug 11, 2010)

jonesy said:


> 60 million lightyears? There must be a unit conversion error there somewhere. I'm just having trouble deciding which one it might be.




Erk.....just a tad.....that should have said 60 light years....but I think while writing it I was thinking it may as well take 60 million years to get there, at current speeds.



jonesy said:


> But with the distances involved it hardly matters.
> 
> The closest star is Proxima Centauri at 4.2 lightyears. That's about 40 trillion kilometers.
> 
> ...




I didn't think we had stars that "close" to us.  I thought they were much further out.  In any case, do we really *know* that no stars closer than 300 light years away have planets?  Or have we just not seen them yet?  As far as I know, it's only in the last 10-20 years that we've been starting to actually, definitely "see" planets around other stars.  My understanding is that even with the best telescopes, we don't "see" planets around other stars...we mainly get guestimate that they're there, based on seeing refracted light that tells of the presence of certain gases or minerals that indicate planets, or calculate based on analyzing gravitational movements of other stars, which indicate planetary bodies are circling them.

I'd guess that there are a lot more planets out there, even in our close neighbourhood, and it's just that our instrumentation isn't powerful enough to detect it yet.  Plus, budgets applied to finding planets etc. are still limited, hence we might be able to find more planets closer, sooner, if we were able to throw more money into detecting them.

Similar to how budgetary limitations mean that we're really blind to how many space rocks with civilization or nation-ending potential are out there, on possible collision courses.



jonesy said:


> The fastest theoretically viable stardrive at the moment seems to be nuclear pulse propulsion (correct me if you find something faster, please). The Project Orion. It would get you to Proxima Centauri in 85 years. If you used the Ion drive we now have working, 8000 years. Yeah.
> 
> Edit: sorry, now I made an error: the ion drive would get you to Proxima Centauri in 80000 years.




So, again, barring some kind of technical discovery, such as figuring out that wormholes exist in anything besides the theoretical, and then actually using them to move vast distances instantly, we don't have any conclusive way to move to these other star systems in any approximation of feasible time periods.  I mean, Michael Crichton did it in "Sphere", but who knows if that will ever happen?

I'm not sure we'll ever get nuclear drives working for space travel.  And even if we did have a craft capable of going 90% of the speed of light, and as a result, we get to a star that is 4.2 light years away in 4.6 years.......isn't there a dilation effect whereby people left behind on earth will have experienced a longer period of time?  Or is that not correct?  If it *is* correct, how much time would have passed on earth while they were traveling to the next star?

Of course you never know.  Science is progressing rapidly in a lot of fields.  I had read that cryogenic suspension was basically science fiction....because when they try to "thaw" subjects after suspending them the cells rupture, and they die (when working with cells in the lab, not with human test subjects).  But I've also read that in the last 2-3 years, they've been making strides, and they're talking about experimenting with extreme cold used to slow or suspend physiological activity in accident victims, in order to improve survival rates in trauma victims.  The article had commented that most trauma victims who die, die because they bleed out before the doctors can fix the damage.  So if they can slow down the body's systems so that doctors can repair the damage, the person could be brought back once the damage is repaired.

And if they can do that, it would likely be a big step in the right direction to some kind of cryogenic suspension, you would think.

As to whether to colonize other planets or not.  As a matter of species survival it makes sense, if possible.  All it would take is one bad day encountering a space rock, and that's it for homo sapiens.  Heck, we could have a day that's bad enough to maybe not kill everyone, but eliminate 99% of the global population, and send us back to the stone age.

Haven't astronomers said something about human civilization having evolved during a period when our solar system was passing through a part of the galaxy where there was a relatively low level of space clutter, but we're moving back into the busier areas?  Obviously solar systems move very slowly.....but the technological, practical, and financial advances to get us to other planets are so significant, what is the likelihood we get anywhere before we get hit by something big?

And if it's not that, global climate change could make things unpleasant, we could run out of certain needed materials/supplies, have a global nuclear conflict, or run into the next ice age.  Any of those things could put us in a position where we have no resources to devote to space travel.

Banshee


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## Banshee16 (Aug 11, 2010)

Umbran said:


> Yep.  Probably ion engines run off a small nuclear power plant.
> 
> 
> 
> ...




60 to 70 years to reach another star.  That's an immense amount of time.  I don't think it's even practical to contemplate.  You basically either need to have one of two things (IMO):

A) Super-developed AI's, in combination with workable cryogenic technology allowing you to freeze your crew, and only bring them out in moments of crisis, or when you are almost at your destination.

or

B) A super huge ship with a large population, more than we've ever put into space before.  60 or 70 years?  Assuming that your astronauts are 20 years old when they launch, they're going to be 80 or 90 years old when they get there.  So either you've got astronauts who have enough life in them to push some buttons and make sure to be able to send a message back to say "yeah", there's a good planet here, send the next ship...with that message getting home in how many years after that?  Or you have to have that ship with a huge population, so that you can support astronauts having babies in space, with all the medical complications and supply issues that entails...because it's going to be 3 generations after liftoff that you finally get where you're going.

To me it just doesn't seem realistic.  I don't think it means we don't look for solutions...I just kind of think that getting to another solar system is more science fiction fantasy than anything else.  Look how much human civilization has changed in 70 years.  How can you stick astronauts on a ship to another solar system, and have them arrive 70 years later, sane, unless basically what you're sending is a colony ship of sorts?

Banshee


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## Pbartender (Aug 11, 2010)

jonesy said:


> Yikes. Does that scale accordingly? If you need a bigger lump of the stuff, do you also need a bigger ring and magnets?




It depends on what your goal with the antimatter is...

The circumference of the ring is determined by the energy of the particles you are containing.  If they're more energetic (in general, and before relativity takes too much effect, moving "faster"), you need need either a larger circumference or more powerful dipole magnets to keep them turning the circle.  Think of it like a race track...  Really fast cars need a very gradual turn or a very steep embankment to keep from flying off the road when they turn.  Of course at the aforementioned Fermilab, energy is important, since the antiprotons are being used for collider experiments.  Higher energy == better experimental results.  When storing for propulsion purposes, the "speed" of the particles is less of a concern, so it's likely a storage ring for such purposes could be of a much smaller diameter.

However, there's another problem...  particles with similar charges repel each other.  The antiprotons we use at Fermilab, for example, are all negatively charged, which is what allows us to use magnetic fields to store them by spinning them around in circles.  Anyway, what this means is, when you have a group of like-charged particles hanging out, they tend to disperse since they all repel each other.  That means you have to actively focus the beam using a host of tricks like quadrupole, sextupole and octupole magnets, and radio frequency stochastic cooling systems, and blah-blah-blah sounds like it's straight out of a Star Trek episode.

That's what's holding us up.  The more you store, the harder it is to hold it in.  Our current technology isn't good enough to make and store much more than a speck, and while advances are being made, it's not a high enough priority to spend the sort of time and money on it that we'd need to in order to turn it into propulsion.

It's not like in _Angels and Demons_ where you can just hold enough antimatter to blow up a small city in a glass jar the size of a two liter bottle of soda powered by nothing but a couple of rechargeable D-cell batteries and carry it around with you.


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## Orius (Aug 11, 2010)

El Mahdi said:


> Right now, it looks like the leading impetus for any type of colonization on the moon might be commercial tourism.  As for official research and exploration type colonization, it seems to be on permanent high-speed hold.  Until the world's economies significantly improve, I just don't see it happening.




Yeah, space tourism is likely to be the main impetus in the near future, the super-rich have run out of places to see here on Earth so the need to go into space to brag about something.  

A lot of the problem is politics and a lack of vision to go into space.  Exploration in the past was carried out partially because expanding empires were looking to conquer new territory.  But there's a view in many of the nations who currently have any space flight capabilities that the whole nation-state concept is outdated and shouild be discarded, and that the whole space race was just a bunch of worthless patriotic chest-thumping that did nothing but plant a flag on the moon and bring back some rocks and dirt, and thus was a colossal waste of money, we should take care of our own problems instead.  Never mind that one such problem that is nearly always brought up is poverty, which we haven't gotten around to solving in 6 odd millenia of recorded civilization.  If we could solve it in that much time is it worth the effort, or do our thinkers and moral authorities think they can do so because some of their ethics are different from those of the past?  My problem with that is if you look for excuses not to go into space, you'll never develop any of the needed technologies or propulsion to do so.

At least some nations aren't so blinded by such thinking.  We'll need it eventually, because I agree with Hawking's assessment; staying stuck on Earth indefinitely will lead to our eventual extinction.  Even if we don't wipe ourselves out, the world cannot sustain us forever, even it can do so for a million lifetimes.  And we're not just a herd of stupid animals acting on instinctive impulses to feed and mate (well _sometimes_ we aren't), we're aware of our existance and the likely potential for our own eventual extinction.  Some people have children because they know someday they will die, and they hope they can raise their children to influence the next generation.  Trying to get offworld does this for the whole human race, getting offworld is the only way we can ensure the survival of humanity over the very long term.  The only extinction of _H. sapiens_ I am willing to accept is one that happens after a new species of _Homo_ has emerged and carries on our legacy.  Anything else to me is absolutely morally unacceptable.


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## Knightfall (Aug 11, 2010)

One problem I foresee regarding the colonization of an exoplanet that can sustain life is biological. There is no way from us to be certain that being exposed to an alien biosphere wouldn't kill the colonists.

Heck, that could even be a problem on Mars if their turns out to be some form of microscopic biological lifeform on the planet that turns out to be harmful to humans.


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## jonesy (Aug 11, 2010)

Banshee16 said:


> In any case, do we really *know* that no stars closer than 300 light years away have planets?  Or have we just not seen them yet?



Pretty much every single planet that we've detected has been Jupiter-like. So, yes, we aren't seeing the small ones yet. If the big ones are there, the little ones must also exist.

Edit: when I say Jupiter-like, I mean easy to see. =)



Knightfall said:


> Heck, that could even be a problem on Mars if their turns out to be some form of microscopic biological lifeform on the planet that turns out to be harmful to humans.



Oh, we don't need there to be anything for that. The tiny stuff we bring along will be just fine. Once the bacteria we carry along adapts to Mars, it has a chance of being a degree of hostile to us.


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## Hand of Evil (Aug 11, 2010)

Just saw this and said to myself; WOW! Plasma rocket may shorten space voyages

Also another link: http://cosmiclog.msnbc.msn.com/_news/2010/08/10/4863282-next-giant-leaps-for-nasa-tech



> An innovative plasma rocket being built as a spare for one heading to the International Space Station may have a space mission of its own: visiting an asteroid.
> 
> Equipped with an electric propulsion system, the rocket, known as Variable Specific Impulse Magnetoplasma Rocket (VASIMR), is being developed to one day transport astronauts to Mars in 39 to 45 days — a fraction of the six to nine months the trip would take with conventional chemical rockets. Shorter travel time greatly reduces astronauts' exposure to potentially deadly cosmic and solar radiation, currently a show-stopper for human missions to Mars.
> 
> ...


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## jonesy (Aug 11, 2010)

Hand of Evil said:


> Just saw this and said to myself; WOW! Plasma rocket may shorten space voyages
> 
> Also another link: Cosmic Log - Next giant leaps for NASA tech



That. Is. Cool.

Anytime there's been new talk of the VASIMR someone mentions that you'd need nuclear power to reach usable powerlevels. Now they're saying they can get it up and running with just solar power? Awesome.


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## Pbartender (Aug 11, 2010)

jonesy said:


> Pretty much every single planet that we've detected has been Jupiter-like. So, yes, we aren't seeing the small ones yet. If the big ones are there, the little ones must also exist.




That's not exactly true...  

If you check the list of Extrasolar Planets, we've discovered at least a dozen that are no more than ten times the mass of the Earth (Earth's mass is ~0.00315 Jupiter masses).  

One of them, Gliese 581 e is less than twice the mass of Earth.

Another, COROT-7b is nearly fives times the mass of Earth, but has actually had it's diameter measured at 1.7 that of Earth's, and has been determined to be almost certainly a terrestrial-type planet.


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## jonesy (Aug 11, 2010)

I did amend that I meant 'easy to see', and not 'giant gas planet'. 

And those are both pretty HOT.


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## Pbartender (Aug 11, 2010)

jonesy said:


> I did amend that I meant 'easy to see', and not 'giant gas planet'.
> 
> And those are both pretty HOT.




Absolutely, they are...  More like really big Mercuries, than Earths.  But still, it bodes well for the future of our exoplanet detecting abilities.

But something else that a lot of people forget about is that gas giants tend to a lot of moons...  and very often, large moons.  Consider that every Jupiter-like planet we see could have one or more Earth-like satellites that we can't see.  If the gas giant is within its star's Goldilocks zone, some of those moons could be habitable.


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## Umbran (Aug 11, 2010)

Banshee16 said:


> I didn't think we had stars that "close" to us.  I thought they were much further out.  In any case, do we really *know* that no stars closer than 300 light years away have planets?  Or have we just not seen them yet?




The closest known planet outside our solar system is 10.5 light years away.  There's only a handful of starts under 10 LY from Earth.

The other known planets outside our solar system are mostly _less than_ 300 light years away, not greater than.  That's just because finding planets is harder the farther away the star is, so they've been concentrating on nearby stars in the search.



> As far as I know, it's only in the last 10-20 years that we've been starting to actually, definitely "see" planets around other stars.




The first *direct* image of a planet around another star using visible light was taken in 2008, and only confirmed in this past June.

SPACE.com -- First Direct Photo of Alien Planet Finally Confirmed







> Haven't astronomers said something about human civilization having evolved during a period when our solar system was passing through a part of the galaxy where there was a relatively low level of space clutter, but we're moving back into the busier areas?




The Earth takes about 200 to 250 million years to make an orbit around the center of the Milky Way Galaxy.  Civilization is only about 10,000 years old.  In terms of moving around the galaxy, the Earth has gone next to nowhere since civilization began.



> Obviously solar systems move very slowly.....but the technological, practical, and financial advances to get us to other planets are so significant, what is the likelihood we get anywhere before we get hit by something big?




I think you may not quite grasp the scale here.

The chance that the Earth will get hit by an object from outside the solar system is, for all practical purposes, zero.  Space is big.  Really big.  Really vastly empty big.  There's only a handful of stars within ten light years of Earth now, and that's only going to change on the order of millions of years, not thousands.  For our purposes, there is nothing out there to hit us, and we are such a tiny target that hitting us is nigh impossible.

Now, getting hit by a rock that's already within our own solar system?  That we can show has happened rather frequently in the past, so that it is likely to happen again.


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## jonesy (Aug 11, 2010)

Umbran said:


> I think you may not quite grasp the scale here.
> 
> The chance that the Earth will get hit by an object from outside the solar system is, for all practical purposes, zero. Space is big...



The statistical chances of getting hit go up when one considers how long Earth has been around for it to be hit.

But then again they go down when you consider that we've already been hit by at least one global killer. Possibly more. There wasn't anything here to kill before that. Or maybe there was and it was a total kill. There's a cheerful thought.


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## Pbartender (Aug 11, 2010)

Umbran said:


> I think you may not quite grasp the scale here.




[ame=http://www.youtube.com/watch?v=f_J5rBxeTIk]YouTube - ‪Yakko's Universe Song‬‎[/ame]

It's a great big universe, and we're all really puny. We're just tiny little specks about the size of Mickey Rooney. It's big and black and inky, and we are small and dinky. It's a big universe and we're not.


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## Umbran (Aug 11, 2010)

jonesy said:


> The statistical chances of getting hit go up when one considers how long Earth has been around for it to be hit.




A bazillion times zero. 

You are technically correct, the chances do rise.  However, we aren't talking about timespans the order of the age of the Earth - we are, for the moment, discussing things happening within human civilization - timespans on the order of a handful of thousands of years.  



> But then again they go down when you consider that we've already been hit by at least one global killer. Possibly more.




At this point, being hit in the past does not really decrease (or increase) the chance that we'll be hit again in the future.  Once the solar system was mostly stable, it became a coin-toss sort of thing, and if you flip it often enough, eventually that coin comes up heads.

We've been hit by several rocks that have wiped out over 50% of species on the planet.  And we've been hit once by something that would have wiped out everything but microorganisms, had they existed, when the Moon was made.

But all those came from _*within our solar system*_.   The post I was responding two was talking about getting hit by something from outside our solar system.  I know of no evidence that we've ever been hit by anything from outside the local area of Sol.


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## jonesy (Aug 11, 2010)

I trust you've all seen this (which is already out of date, and I can't find the original):
[ame=http://www.youtube.com/watch?v=Tfs1t-2rrOM&feature=related]YouTube - ‪Planets and stars size in scale‬‎[/ame]

When I showed this to my dad all he managed to say was "ups":
[ame=http://www.youtube.com/watch?v=17jymDn0W6U]YouTube - ‪The Known Universe by AMNH‬‎[/ame]


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## Joker (Aug 11, 2010)

jonesy said:


> I trust you've all seen this (which is already out of date, and I can't find the original):
> YouTube - ‪Planets and stars size in scale‬‎
> 
> When I showed this to my dad all he managed to say was "ups":
> YouTube - ‪The Known Universe by AMNH‬‎




Your mom is so fat she makes W Cephei look like the sun.

Amirite?  High five*


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## hafrogman (Aug 11, 2010)

Umbran said:


> Space is big.  Really big.  Really vastly empty big.



Space is big. You just won't believe how vastly, hugely, mind- bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.


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## Starman (Aug 12, 2010)

Pbartender said:


> It's a great big universe, and we're all really puny. We're just tiny little specks about the size of Mickey Rooney. It's big and black and inky, and we are small and dinky. It's a big universe and we're not.




Funny, but this is my favorite space song.

[ame=http://www.youtube.com/watch?v=buqtdpuZxvk]Galaxy Song[/ame]


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## Pbartender (Aug 12, 2010)

Starman said:


> Funny, but this is my favorite space song.




Oh, I thought about that one...  Except that I wasn't entirely certain what Eric's Grandma would have thought about that bit in the middle.


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## TanisFrey (Aug 12, 2010)

hafrogman said:


> Or you land there and declare independance as a sovereign nation, unconstrained by treaties you're not a signatory body to.  Of course, this leaves all the other nations of the planet free to invade you ... but given the prohibitive cost of getting bullets, guns, soldiers and tanks to the moon ... you could be pretty safe.



No, only one nation could invade.  The one the colony breaks away from.

There is another treaty saying that a space ship is the territory of the nation that launched it.  Therefore only the nation of the place where the colony launched from could invade without sanction from the UN.


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## jonesy (Aug 12, 2010)

TanisFrey said:


> No, only one nation could invade.  The one the colony breaks away from.
> 
> There is another treaty saying that a space ship is the territory of the nation that launched it.  Therefore only the nation of the place where the colony launched from could invade without sanction from the UN.



Use a spaceship from a country that can't or won't retaliate into space to create you own space-nation and you're safe from everyone? Supposing there was such a country with its own space-program I doubt it would be quite that space-easy.


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## Pbartender (Aug 13, 2010)

Invade, schminvade.

All they need to do is drop a really fast rock on top of your moon base...  It doesn't even have to be a very big rock.

Problem.  Solved.


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## Banshee16 (Aug 13, 2010)

Umbran said:


> The closest known planet outside our solar system is 10.5 light years away.  There's only a handful of starts under 10 LY from Earth.
> 
> The other known planets outside our solar system are mostly _less than_ 300 light years away, not greater than.  That's just because finding planets is harder the farther away the star is, so they've been concentrating on nearby stars in the search.
> 
> ...




I don't think I'm misunderstanding the scale.  It's all a matter of statistics.  I don't think I said that the Earth has passed all the way around the Milky Way in 10,000 years.  What I was saying was that the article I'd been reading had suggested that we've experienced a period of thousands (or a few million, can't remember the number) of years of time, wherein Earth was going through an area of the Milky Way where there was less debris.  As a result, we may have had lower numbers of large impacts.....a stability that partly enabled the development of human civilization.  The article said that the space ahead may be rougher, increasing the chance of large impacts.

There are space rocks out there of all sorts of different sizes.  We know we've been hit by different rocks over hundreds of millions of years.  There are craters of various ages all over the earth.  Heck a guy was in the paper earlier this summer for getting his by a speck of cosmic dust (relatively speaking) that burned a hole through his hand.  I saw a picture of a car that got hit by a small one, which basically destroyed an end of the car.

This stuff hits us.  Most of it gets burned up in the upper atmosphere, but every so many thousand or million years, something bad happens, and we get hit by something bigger.  It's not like the rock that created the Chixculub crater and contributed to the major extinctions 65 mya was the first large rock that's hit us.  There's some evidence apparently that an extrasolar event,  possibly another meteor strike contributed to a mass of extinctions among megafauna 10,000 + years ago.

Statistically, we've been hit before, and we'll be hit again.  The longer we go without a big strike, the greater become the odds that we *do* get hit again.  That doesn't mean tomorrow, or in 10 years, 100 years, 1000, or 10,000.  But it's likely going to happen.  When is the question.  If it's 1,000,000 years from now....well, humanity might not be around anymore....or our descendents might not be recognizable to us at that point, so for all intents and purposes it wouldn't matter.

It's just like earthquakes.  Everybody buys earthquake insurance right after an earthquake occurs.  But that's when, statistically, you're less likely to have another major quake.  But if you're in a quake zone, then every year that goes by without a quake increases the chances one *will* occur....making having insurance against it more and more important.....yet people become less and less likely to buy that insurance, the longer it goes without a quake.

I absolutely know that space is vast.  Immensely vast.  There's lots of emptiness out there.  But there are also rocks and other things, each with their orbit, as our planet has an orbit, our sun has an orbit, and even our solar system has an orbit.  Everything's out there moving around.  But we know that there there are big rocks in and around our solar system perfectly capable of radically transforming life on this planet, by wiping out pretty much every mammal bigger than a mouse.  So....Spaceguard has been working to collate information about all the rocks 1 mile across or bigger, and is supposed to have identified 90% of them by now.

But governments haven't been able to put together enough funding of $300-400 million, to allow them to identify 90% of asteroids 140 - 1000 m in size.  These are the rocks fully capable of obliterating a country the size of India, with like 16% of the world's population.  That would be an example of a very bad day that doesn't destroy civilization as we know it.

Now aside from knowing that the rocks are there, I'm not sure if we even have the capability to do anything about them.  I don't think we'll be landing Ben Affleck and Bruce Willis on an asteroid anytime soon.  And if we *do* develop the ability to interfere with one of these space rocks, and prevent a collision, we still have to *find* them......and we're not really looking (for rocks between 140 and 1000 meters) from what I understand.  At least not in an organized fashion.  I do think it would be nice to know.  Our calculations are good enough that scientists can look at an asteroid, observe its orbit, and say "well, it'll come close in 2079, but not close enough........but 2208 might be a bad year for somebody or many somebody's".

The *chances* of any of this happening are very low in our lifetimes.  But they're not 0.  Spread that out over a longer period of time.....100, 500, 1000 years, and they start to climb.  If the Tunguska explosion of 1908 was in fact an asteroid detonating in the atmosphere, it's evidence of the scale of the problem.  There's lots of uninhabited land (and water) on earth.  But imagine if that event had happened over a city, instead of over Siberia.

Volcanoes are another way that life can be negatively impacted.  They're the main suspect behind the Jurassic extinction event, are they not?  Where 50% of life on the planet was wiped out?  It doesn't even take something that major.  The volcano eruption in Iceland this summer caused how much interference to air travel?  How much money was lost?  And that was a relatively small one, from what I understand (geologically speaking).

In any case, the only reason I brought this up is to basically to illustrate the point that space is big (heck, earth is big), and man is small.  We can control what we can control.....and you just cross your fingers the rest of the way.  And I'm not saying this to indicate that I think an asteroid's going to hit tomorrow.  Or the day after.  Or the year after.  The greater the perceived negative effect of something happening, the greater the chance we estimate that it will actually happen.  I understand that.  A big rock wiping out all life on the planet?  Possible, but unlikely.  A big rock wiping out a country?  More possible, but still unlikely.  A big rock wiping out a city?  Probably even more possible, but still very, very unlikely.  An individual is still in far greater danger smoking, driving their car, or drinking pop.  Someone's probably more likely to get hit by a bus, while worrying about getting hit by an asteroid .

But if we're dreaming big dreams, and wanting to ensure that humanity survives, then exploration of space becomes a necessity, rather than sitting here on this one planet.  And that kind of project, such as terraforming Mars, could take hundreds of years.  A project like that is  probably more likely to happen than flying to another solar system and populating a planet 10 light years away.  But I think that the resources and political will to do any of this aren't really there.  I mean, in many democracies, people can't even come to an agreement about whether or not to build a bridge in one place or another.  And we're talking about coming to agreements about colonizing other worlds?

I had read that, despite the expense of the NASA space program, the Apollo missions, and all of that, these explorations have still resulted in scientific and technological advances that resulted in financial benefits that significantly outweighed the expenses of those programs.  But the voting and tax paying public of many nations doesn't really *get* it.  So I'm not sure that the political will will be there to support the work needed to accomplish these kinds of long term goals.

So, this is why I think we *should* be doing it, but that I don't think it's going to happen.

Banshee


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## jonesy (Aug 13, 2010)

I think that the Spaceguard Survey operations around the world are a good idea and should receive more funding. But they can't protect us from the worst case scenario which is something coming at us at a high velocity. It doesn't even need to be big. With enough speed it could even be something too small to reliably notice. You might be surprised at how small an object could be to destroy the planet if it came at us at a relativistic speed. Then again you might not. The point I'm trying to make is that something like that doesn't need to be intentional or even that improbable. A supernova explosion somewhere out there could propel stuff at those speeds.

For a good book on relativistic death, and a good scare, find a copy of Pellegrino's The Killing Star.


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## Umbran (Aug 13, 2010)

Banshee16 said:


> There are space rocks out there of all sorts of different sizes.  We know we've been hit by different rocks over hundreds of millions of years.




Yes, but here is my point: *those rocks did not come from outside our solar system*.  They came from _within_ our solar system.

Our being hit by "debris" from outside our solar system isn't a realistic risk.  The materials of interstellar space are so diffuse, and our planet is so small compared to the space involved, that the statistics show a collision, even on geologic timescales is just not going to happen.  This is why I say you might not understand the scales involved.  Space is so _incredibly huge_, and there's so little matter in it, that this just isn't a concern.

Now, if you want to say that our sun will be passing through a region in which there are more stars, and one of those passing nearby and might give a gravitational nudge to things in our own Oort cloud and that's a risk, you might have something.

Except that the nearby stars are well charted, and their velocities relative to us are known.  None of them are on a path that's going to be an issue in the next few tens of thousands of years, as I understand it.



> So....Spaceguard has been working to collate information about all the rocks 1 mile across or bigger, and is supposed to have identified 90% of them by now.




Yes.  And all those rocks are within our solar system.  None are "extrasolar".

I will say once more, just to be 100% clear.  Getting hit by something is a notable risk.  Getting hit by an object from outside our solar system is not a notable risk.  You've got the right general idea, but you're attributing a danger from the wrong place.

I'm sorry if I seem to be harping on this.  I'm a physicist by training, and when I see policy-influencing misinformation, I feel a bit obliged to correct it.



jonesy said:


> You might be surprised at how small an object could be to destroy the planet if it came at us at a relativistic speed.




Yes, but objects moving at relativistic speed are few and far between.  More rare than even non-relativistic objects.  While it makes good theater, it is not a realistic risk.

If you want death from outside our solar system, worry about gamma ray bursts.


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## jonesy (Aug 13, 2010)

Umbran said:


> Yes, but objects moving at relativistic speed are few and far between.



Yeah. You're right. I'm not going to argue that getting hit by one is realistically probable. I just meant that accidental death by fast moving pebble is realistically possible. In this instance possible and probable couldn't really be any further apart.


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## Bullgrit (Aug 13, 2010)

> I'm not going to argue that getting hit by one is realistically probable.



Well, aren't the odds . . . relative.

Bullgrit


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## Banshee16 (Aug 13, 2010)

Umbran said:


> Yes, but here is my point: *those rocks did not come from outside our solar system*.  They came from _within_ our solar system.
> 
> Our being hit by "debris" from outside our solar system isn't a realistic risk.  The materials of interstellar space are so diffuse, and our planet is so small compared to the space involved, that the statistics show a collision, even on geologic timescales is just not going to happen.  This is why I say you might not understand the scales involved.  Space is so _incredibly huge_, and there's so little matter in it, that this just isn't a concern.
> 
> ...




Hey, I'm not going to dispute your expertise.  My training is in stats, business, and psychology.....not physics.  I'm no expert.

The articles I'd read about our solar system's position, and objects from outside our solar system being a possible threat wasn't really talking about calculating risk for anybody in the near future.  I think they were more hitting on theoretical risks down the road.  Of course, what things will be like in 90,000 years, or 900,000 years is beyond anyone's ability to predict, when the weathermen can't even get the weather right two days in the future   A really basic statement is that pretty much any prediction, and most prognosticators are right 50% of the time.  And wrong 50% of the time.

I'm not sure if astronomers or physicists are able to reliably determine where something that his us 65 million or 200 million years ago came from.  Can they know *for sure* that a particular rock, that long ago, didn't come from outside the solar system?  I frankly don't know.

Regardless, I think we're in general agreement that knowing where these rocks are, and if they're on collision courses is pretty important.  They don't have to be outside our solar system to be a threat.  There are enough of them within our solar system, on various orbits.  Now, maybe I'm wrong, but I would think that the civilization ending rocks over 1 mile in size are the "big daddies" of space rocks, and likely the lowest quantity.  Then, the ones that are between 140 and 1000m in size are much more common.  And then rocks smaller than 140 meters are even more common than that.  Does that statement agree with your training?

When they identify these rocks, particularly the large ones, which I think they've identified most of, have they been able to definitely determine that none of them are on courses likely to intersect with us?  Or simply that they're not likely to intercept us in the next 500 years, but in 1200 years, or 11000 years, they might come really close?

I think that the fact that the smaller rocks can still inflict enough damage to wipe out a relatively large country is still a problem.  Of course, the *probability* of it happening is likely not high.  But because the funding isn't there, we just don't know.  Could you imagine the chaos if a space object 400m in size hit a city in North America?  It's not like it would turn Canada, the U.S. or Mexico into a giant crater.  But the blast wave and everything would likely kill everything in a pretty wide radius, throw up a lot of debris to cut off sunlight etc.  It's not like it would have to cut off sunlight for years.  Even if it did it for several weeks to a month or two, what kind of plant life or crops would survive in the immediate area?  If the degree of sunlight reduction is similar to that caused in the vicinity of volcanic eruptions, it would be utter chaos.  I saw video of an eruption from several years back, and at noon it was pitch black.  There was no visibility.  My city got hit by the ice storm back in 98, and there was chaos at times.  People breaking into places, generators being stolen.  Driving down the streets at night was eerie...no power for days, or weeks in some areas, complete blackness.  And that was just at night.  Imagine that lasting 24/7?

In any case, Earth itself has far more ocean than land, so even if the planet did get hit again, it's far more likely to hit an ocean somewhere rather than a city.  Again, just talking statistically.

In any case, we're talking very small chances.  I mean it doesn't mean we should ignore the threat....but we shouldn't we wandering around ducking either, because it's unlikely to happen in any of our lifetimes.

Because of how big the universe is, and the sheer enormity of the technological and financial requirements posted by the idea of colonizing another planet, even in our own solar system, I think we're talking about relatively slow, long-term developments.  If we do decide to go ahead with colonization (of Mars for example), even if we know it's theoretically possible, we may not be able to practically do it for hundreds of years.  I want to draw a line in the sand to establish what I'm thinking of when I saw colonization.  I'm not talking about sending a craft to Mars and planting a flag there.  I'm talking about an actual, livable environment....not just a remote science station where a select few scientists are sent to do research.  I'm meaning a living, semi-permanent community where people are living, working, and even having babies etc.  Maybe not entirely self-sustaining....but growing.  Is it likely such an environment could exist in a bunch of bubbles?  Longterm?  You'd need to have scientists, engineers, doctors.....and all the support people that help them do their jobs...nothing we've done as a species so far compares, with respect to putting people into such a hostile environment, longterm...in relatively large numbers.

So I figure it'll take awhile.  And if it takes awhile, then the numbers and risks associated with having all of our population on one planet start to look a little more risky.  I'm not saying it's a problem in 2010.  But what about 2817?  Or 3689, or 7982 AD?  Or even further out?  I use those years, because the mind can still kind of conceive of that span of time.  Of course, given how much human civilization has changed between 1500 BC and 2010 AD, it's hard to imagine where we'll be at in 7982 AD.  Or 21,385 AD.  Or 91,998 AD.  It boggles the mind.  And cosmically speaking those are mere seconds......though I'm sure if humanity is still around at that point, our descendants would be pretty much unrecognizable to us at that point....maybe not from a physical evolution standpoint.  But from a civilization standpoint.

Of course, the range of our scientific knowledge is constantly expanding, and we tend to find new ways to both push the boundaries of what we know, and find solutions to things that we once thought were hard and fast limitations.  Maybe researchers 900 years from now will look back at Eistein's theories as advanced for the time, but quaint by the science we have 900 years from now.  Maybe at that point, we'll have technology that can get us to another start in days or weeks.  Who knows?  I think it would be fascinating to *know* and experience those kinds of things, to stand on the shore of a planet orbiting another star......but I don't know if it'll happen.  I'd like to know about if there's life out there.  Given the size of the universe, it would seem kind of a waste if we were the only planet with life.  Statistically, it's unlikely.  But in any case, we're so immersed in our own worldview, with knowledge of how life works here that life on another planet could be completely unrecognizable to us.

Anyways, a really good book I read last year was "Risk: The Science and Politics of Fear" by Dan Gardner.  It talks about a few of these things (meteor strikes etc.), and, in line with your comment about policy-based misinformation, I think you'd find lots of interesting tidbits.  By no means does the author advocate the end of the world.  Most of the book, he talks about how people spend so much time worrying about things that have statistically insignificant chances of occurring, because of how bad they are, and then blithely carry on behaviour that *is* statistically likely to cause them significant harm.  And how governments and corporations play on those fears.  But the idea of the book isn't to blame governments or corporations for playing on fears either.  The author points out the simple fact that governments and corporations are themselves made of people, who are human as are all of us.  They hear about things that could have major negative effects, and worry about them as well.  And as a consequence, they try to implement policies or sell products to mediate those fears.  A big point he makes is how often bad policy decisions are made as a result of a misunderstanding of the true likelihood of something being a problem. Anyways, I found it a very interesting read.

Banshee


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## jonesy (Aug 13, 2010)

Hey Banshee, have you read Kim Stanley Robinson's Mars trilogy? I think you'd quite like it. It's a bit dated, but totally hard science of its time. Robinson imagined a scenario where the polar icecaps on Earth start melting, and everyone rushes to colonize Mars before they drown.



Banshee16 said:


> I'm not sure if astronomers or physicists are able to reliably determine where something that his us 65 million or 200 million years ago came from.  Can they know *for sure* that a particular rock, that long ago, didn't come from outside the solar system?



Yes. They can. Momentum, speed of the object, vacuum, laws of physics, (relatively) close proximity to us. Rocks that travel in space don't just suddenly decide to change their velocity or mass.


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## Umbran (Aug 13, 2010)

Banshee16 said:


> I'm not sure if astronomers or physicists are able to reliably determine where something that his us 65 million or 200 million years ago came from.  Can they know *for sure* that a particular rock, that long ago, didn't come from outside the solar system?  I frankly don't know.




In some cases, that might be determined by sampling material around the impact site - our solar system has a particular chemistry, and things that deviate from that might be an indication of another origin.

But setting that aside, what they can tell is the density of the interstellar medium, and the average size of the particles therein.  They measure a lot of light passing through space, and that light is affected by the stuff it passes through on the way from there to here.

Space is really, really empty.  Items larger than dust grains outside of solar systems are extremely rare.



> Now, maybe I'm wrong, but I would think that the civilization ending rocks over 1 mile in size are the "big daddies" of space rocks, and likely the lowest quantity.  Then, the ones that are between 140 and 1000m in size are much more common.  And then rocks smaller than 140 meters are even more common than that.  Does that statement agree with your training?




Largely, yes.  To quote wikipedia:

"Asteroids with diameters of 5 to 10 m (16 to 33 ft) enter the Earth's atmosphere approximately once per year, with as much energy as Little Boy, the atomic bomb dropped on Hiroshima, approximately 15 kilotonnes of TNT. These ordinarily explode in the upper atmosphere, and most or all of the solids are vaporized.  Objects with diameters over 50 m (164 ft) strike the Earth approximately once every thousand years, producing explosions comparable to the one known to have detonated above Tunguska in 1908.[4] At least one known asteroid with a diameter of over 1 km (0.62 mi), (29075) 1950 DA, has a possibility of colliding with Earth on March 16 2880, with a Torino Scale rating of two."

Objects with a 50 m diameter can cause local disasters.  As noted in the quote, the "Tunguska event" was most likely the result of the impact (well, in-air explosion) of such an object, flatting trees within roughly a 10 mile radius.  These things can destroy a metropolitan area.



> When they identify these rocks, particularly the large ones, which I think they've identified most of, have they been able to definitely determine that none of them are on courses likely to intersect with us?  Or simply that they're not likely to intercept us in the next 500 years, but in 1200 years, or 11000 years, they might come really close?




The search for objects of interest ("Near Earth Objects") is ongoing.  

Current Impact Risks



> In any case, Earth itself has far more ocean than land, so even if the planet did get hit again, it's far more likely to hit an ocean somewhere rather than a city.  Again, just talking statistically.




Hitting an ocean is not necessarily better, as far as humans are concerned.  Most of our cities are on coastlines, and water-strikes can cause tsunamis.  And, for other reasons, once you get bigger than a "city killing" rock, hitting water is very likely worse than hitting land.



> Anyways, a really good book I read last year was "Risk: The Science and Politics of Fear" by Dan Gardner.




Yah.  Humans are known for managing risks very badly.


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## jonesy (Aug 13, 2010)

Umbran said:


> At least one known asteroid with a diameter of over 1 km (0.62 mi), (29075) 1950 DA, has a possibility of colliding with Earth on March 16 2880, with a Torino Scale rating of two.



The NASA page for it is quite informative (it used to have a video explanation, but the link no longer works):
Asteroid 1950 DA

Edit: at the bottom of the page the Tsunami simulation movie does work.


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## Banshee16 (Aug 13, 2010)

jonesy said:


> Hey Banshee, have you read Kim Stanley Robinson's Mars trilogy? I think you'd quite like it. It's a bit dated, but totally hard science of its time. Robinson imagined a scenario where the polar icecaps on Earth start melting, and everyone rushes to colonize Mars before they drown.
> 
> 
> Yes. They can. Momentum, speed of the object, vacuum, laws of physics, (relatively) close proximity to us. Rocks that travel in space don't just suddenly decide to change their velocity or mass.




In general, yes.  But there are other factors like gravity wells of larger objects and such.  A rock that gets close to another object that is much larger might have its orbit affected.....maybe enough to eventually turn a hit into a miss somewhere else, or vice versa.

Similarly, an object doesn't just generally change directions.  But, like a pool ball hitting another, if two objects hit each other by having intersecting orbits (like, say, two large rocks over 1 km in size), assuming they don't shatter into a million pieces, they could end up creating a cluster of smaller remnant pieces, maybe a few of whom are between 140 and 400m in size, which in turn veer off in other directions, according to the energy imparted in them by the collision.  Do physicists watch for that kind of reaction as well?

This is all theoretical at this point.  I'm not really worried about getting hit by a space rock at the moment .

Banshee


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## Banshee16 (Aug 13, 2010)

jonesy said:


> Hey Banshee, have you read Kim Stanley Robinson's Mars trilogy? I think you'd quite like it. It's a bit dated, but totally hard science of its time. Robinson imagined a scenario where the polar icecaps on Earth start melting, and everyone rushes to colonize Mars before they drown.




No, I haven't read those.  Sounds like she's outlining almost a "Waterworld" kind of scenario.

I'm not sure that melting all the ice caps would drown everyone.  I mean, there's a lot of ice in the ice caps....but to cover all the land on this planet?  Though, as pointed out by others, a big proportion of the population lives along the coasts, so people *would* be affected.  I live in the middle of the continent, so I'm not too worried about having my home inundated under a sea.  I do live in an earthquake zone....but we average about 3 "major" quakes a century, and we just had one, so I figure by the time it happens again I'll be almost 70....and in any case, this particular one didn't inflict much damage at all, since most of the buildings here have earthquake tolerance anticipated in their construction.

I don't think I've seen those novels though.  Maybe I'll have to check the local library.

I find the topic fascinating.  I have a brother who's an engineer, and we used to talk a lot about space exploration, what was possible according to science, what was not, etc.

In many ways, if you take out the Cylons, I think Battlestar Galactaca's take on space is probably closer to reality than Star Wars or Star Trek, for instance.  Lots of inconceivably vast, empty space, almost insurmountable distances to cover, incredibly hostile environments, and maybe the very occasional oasis *if* you have some kind of FTL type travel.  Even if we find life, it might not be until we get 300 light years out, and might be something with no sense of resemblance to anything we could expect.  According to the limits of our knowledge, don't scientists think that there could be carbon or silicon based life forms.  But maybe you could have something completely incompatible with us, that breaths different atmospheric gases, has a different kind of lifestyle, and can't be communicated with.  Or we could planets with life, but no intelligent life.  Or ones whose touch is poisonous to us.  Or we finally find a world out there with life on it, but they breath a combination of gases that would be toxic to humans, so we couldn't live there anyways.

And, as someone else mentioned earlier in the thread, even if we found compatible life, that might not be a good thing.  "They" might have bacteria which can make the leap to be able to either affect humans, or have humans act as carriers, so our astronauts bring the bacteria back to Earth, in turn introducing it to other species, or to something in our food supply, which could have very bad effects.

All this is focusing on the negative, of course.  Finding life on other worlds could be one of the things that becomes the most unifying moments we've ever faced as a species.  Instead of humans dividing into groups, and working against each other, we might find a unity in realizing that we're not alone, and that, compared to some of the life out there, skin colour and religion don't matter, and we're all just people.

Banshee


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## jonesy (Aug 13, 2010)

Banshee16 said:


> No, I haven't read those.  Sounds like she's outlining almost a "Waterworld" kind of scenario.



Heh. I totally giggled at the thought of someone calling him a 'she'. Probably a bit too much since I actually called the Dragonlance author Weis a 'he' once. 



> I'm not sure that melting all the ice caps would drown everyone.  I mean, there's a lot of ice in the ice caps....but to cover all the land on this planet?  Though, as pointed out by others, a big proportion of the population lives along the coasts, so people *would* be affected.



Yeah, but it's just one of the ways to get the motivation for the mission. It doesn't quite go all the way. He wrote a book called Antarctica, which I haven't read, but which probably deals with the issue (considering the title, and it being in the same universe as the Mars books).

Edit: I'm trying to find what the link between the trilogy and Antarctica is, but I can't seem to find anything. The blurb says "shares many themes", which doesn't really say anything. Hmm.

The trilogy is great because it doesn't just deal with the tech. It focuses on the political aspect of colonization, and the actual living-on-a-hostile-world angle.


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## Banshee16 (Aug 13, 2010)

jonesy said:


> Heh. I totally giggled at the thought of someone calling him a 'she'. Probably a bit too much since I actually called the Dragonlance author Weis a 'he' once.




I've made the same mistake myself 

Part of the problem with some unisex names these days is you can't even tell them apart by spelling.  You could have Tracey, Tracy, Tracie.......and conceivably any of those spellings could be used for a man or woman.

And there are the others like Morgan, Pat, Eve (up here in Canada, it's perfectly possible to have a male "Yves", which can sound the same as Eve if you're getting the name over the phone), Pascal, Jody....

Banshee


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## Pbartender (Aug 13, 2010)

Banshee16 said:


> I'm not sure that melting all the ice caps would drown everyone.  I mean, there's a lot of ice in the ice caps....but to cover all the land on this planet?




For the record, no. It's not nearly enough to cover all the land on the planet.  If all of the Antarctic ice (roughly 90% of all the ice on the planet) melted, sea levels would rise by about 60 meters (~200 feet).

In fact, it would only affect a relatively small percentage of land.  Although you are correct... as all the affected land is coastal, quite a bit of the world's population would be dislocated.

This website has a set of Java applets that let you play around with changes in sea level.  There's a world map, and also maps for several regions, like Europe, the East and West Coasts of the U.S. and Southeast Asia.

Here's what the world would look like flooded by all its ice:


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## TanisFrey (Aug 13, 2010)

jonesy said:


> Use a spaceship from a country that can't or won't retaliate into space to create you own space-nation and you're safe from everyone? Supposing there was such a country with its own space-program I doubt it would be quite that space-easy.



In legal terms your would be safe.  Until someone decides to ignore the treaty or the UN stepped in.


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## Banshee16 (Aug 13, 2010)

Pbartender said:


> For the record, no. It's not nearly enough to cover all the land on the planet.  If all of the Antarctic ice (roughly 90% of all the ice on the planet) melted, sea levels would rise by about 60 meters (~200 feet).
> 
> In fact, it would only affect a relatively small percentage of land.  Although you are correct... as all the affected land is coastal, quite a bit of the world's population would be dislocated.
> 
> ...




Yeah, I'm pretty sure I'd read that.  I know the media and Hollywood like doom and gloom scenarios, as it does sell.  But I'd read that melting all the ice on the planet would never result in mainland getting flooded.  Coastal areas, yes.....but I don't think people living in Colorado, Utah, Calgary, or Mexico City have to worry, for instance.

Now, what having all those ice caps melt could have disastrous longterm effects to availability of fresh water etc.  Much of the water we drink (at least in my area of the country) comes, at its source, from glaciers etc.  As those melt and disappear, there's going to be less water making its way down the rivers to the areas where people live etc.

I was reading a study on the topic, which was talking about the idea that not nearly as much water comes from rain filling up lakes and rivers as we'd like to think.  Meanwhile, many industrial processes use up significant volumes of available fresh water...for mining, separating oil from the tar sands, etc.

In any case, I don't want to go too far down that avenue of discussion.  And I'm always hesitant around here to give a definitive answer or statement on the boards, as there are plenty of people who post here who have specialized in particular topics.  I'd like to consider myself fairly well read.....but I'm not a specialist in these fields.

I'm just having fun with this particular discussion.  Everyone's being pretty genial about it.

Banshee


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## Banshee16 (Aug 13, 2010)

Pbartender said:


> For the record, no. It's not nearly enough to cover all the land on the planet.  If all of the Antarctic ice (roughly 90% of all the ice on the planet) melted, sea levels would rise by about 60 meters (~200 feet).
> 
> In fact, it would only affect a relatively small percentage of land.  Although you are correct... as all the affected land is coastal, quite a bit of the world's population would be dislocated.
> 
> ...




Cool link!  Looks like Montreal might get rather wet....but it's difficult to tell, because the map only shows Canada in the version that shows the whole world.  Looks like the St. Lawrence would get wider.....so I'm assuming Montreal, Kingston, Vancouver, and maybe even Toronto might have problems.  Toronto's 77m above sea level.  Would an increase to the sea level of 80 m result in major rivers like the St. Lawrence running their banks, and rising (as well as the great lakes)?  Or would it have "no" effect that far in?

Of course, even if flooding was nowhere near on Waterworld scales, you'd still be left with significant human populations being forced to move....which can cause enough problems on its own....to say nothing of the environmental impact on coastal wildlife etc.

Banshee


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## jonesy (Aug 13, 2010)

Pbartender said:


> This website has a set of Java applets that let you play around with changes in sea level.



Huh. Spain stays almost completely dry right up to 400 meters. That surprises me a lot. I never realized it was that high. If there's a waterapocalypse I'm moving there. And if the sea keeps rising you just follow the mountains to the Alps.


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## Umbran (Aug 13, 2010)

Banshee16 said:


> Coastal areas, yes.....but I don't think people living in Colorado, Utah, Calgary, or Mexico City have to worry, for instance.




Well, they don't have to worry directly about the water itself.  But there's climate change associated with that.  And, when NYC, London, Hong Kong, and several other major metropolitan/financial centers take the swim, the world economy collapses.  And every single port in the world is inundated - so no more petroleum shipments...

It's all interconnected.



> Now, what having all those ice caps melt could have disastrous longterm effects to availability of fresh water etc.  Much of the water we drink (at least in my area of the country) comes, at its source, from glaciers etc.  As those melt and disappear, there's going to be less water making its way down the rivers to the areas where people live etc.




Even places not fed by glaciers will likely have weather-pattern changes that alter rainfall, and thus availability of fresh water.



> Meanwhile, many industrial processes use up significant volumes of available fresh water...for mining, separating oil from the tar sands, etc.




That's okay, if the water rises that much, those processes will stop.


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## El Mahdi (Aug 14, 2010)

jonesy said:


> ...Spain stays almost completely dry right up to 400 meters...




But not on the plains...that's where most of the rain falls...


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## Banshee16 (Aug 15, 2010)

Umbran said:


> Well, they don't have to worry directly about the water itself.  But there's climate change associated with that.  And, when NYC, London, Hong Kong, and several other major metropolitan/financial centers take the swim, the world economy collapses.  And every single port in the world is inundated - so no more petroleum shipments...
> 
> It's all interconnected.




Yes, I know   I think I meant more that it's not like those places would be underwater.  The environmental effects would be catastrophic (for current life forms).

To be clear....life has existed on earth in times when water levels were much higher than they are now........*and* much lower.  But, on geological terms, the current moment in time is like nanoseconds in the life of the earth...and the life forms that currently exist are obviously not adapted to the conditions that we'd see with such a rise in sea levels.

Banshee


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## catsclaw227 (Aug 20, 2010)

Aren't the chances of Yellowstone busting it's nut higher than getting hit by a space rock?  Being a super volcano, it could do far more damage than a 50m asteroid hitting.  

Apparently it has an alarmingly regular eruption cycle determined to be every 600,000 years, and the last eruption was more than 640,000 years ago, so we're more likely to be wiped out by this than anything extraterrestrial.

Yellowstone also got scary active just after the Haiti quake, with a reported 1620 small quakes between Jan 17, 2010 and Feb 1, 2010, being the second largest swarm of quakes in the Yellowstone caldera ever recorded.

One online chicken-little has this to say about what would happen if it erupts.  (note, I don't know where he gets the science from):



> Immediately before the eruption, there would be large earthquakes in the Yellowstone region. The ground would swell further with most of Yellowstone being uplifted. One earthquake would finally break the layer of rock that holds the magma in - and all the pressure the Earth can build up in 640,000 years would be unleashed in a cataclysmic event.
> 
> Magma would be flung 50 kilometres into the atmosphere. Within a thousand kilometres virtually all life would be killed by falling ash, lava flows and the sheer explosive force of the eruption. Volcanic ash would coat places as far away as Iowa and the Gulf of Mexico. One thousand cubic kilometres of lava would pour out of the volcano, enough to coat the whole of the USA with a layer 5 inches thick. The explosion would have a force 2,500 times that of Mount St. Helens. It would be the loudest noise heard by man for 75,000 years, the time of the last super volcano eruption. Within minutes of the eruption tens of thousands would be dead.
> 
> The long-term effects would be even more devastating. The thousands of cubic kilometres of ash that would shoot into the atmosphere could block out light from the sun, making global temperatures plummet. This is called a nuclear winter. As during the Sumatra eruption a large percentage of the world's plant life would be killed by the ash and drop in temperature. Also, virtually the entire of the grain harvest of the Great Plains would disappear in hours, as it would be coated in ash. Similar effects around the world would cause massive food shortages. If the temperatures plummet by the 21 degrees they did after the Sumatra eruption the Yellowstone super volcano eruption could truly be an extinction level event.




Sounds scary.  But does anyone know how much of this is true and how much is 2012 style fear-mongering and superstition?  

I mean, geological technology is getting pretty good, and they say that the ground in the Yellowstone caldera is 74cm higher than in 1923, and scientists from the USGS used InSAR (Synthetic Aperture Radar Interferometry) to map the changes in the northern rim of the caldera and discovered it had risen about 13cm from 1997 to 2003.

I don't know, but that concerns me more than an asteriod.


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## jonesy (Aug 20, 2010)

catsclaw227 said:


> Sounds scary.  But does anyone know how much of this is true and how much is 2012 style fear-mongering and superstition?



There have been three supereruptions. 2.1 million, 1.3 million, and 640k years ago. But when it comes to volcanoes that doesn't mean much. You can't really use times of past explosions to calculate times of future explosions. It might blow up tomorrow, or never again.

Like Wikipedia mentions: "University of Utah and National Park Service scientists with the Yellowstone Volcano Observatory maintain that they see no evidence that another such cataclysmic eruption will occur at Yellowstone in the foreseeable future. Recurrence intervals of these events are neither regular nor predictable."

If you want to scare yourself here's a BBC dramatization:
[ame=http://www.youtube.com/watch?v=XAf6OyFth7Y]YouTube - supervolcano part 1 2/6[/ame]


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## El Mahdi (Aug 21, 2010)

catsclaw227 said:


> ...Sounds scary. But does anyone know how much of this is true and how much is 2012 style fear-mongering and superstition?...




I've got it on good authority that this is actually scheduled for 2012...


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## Banshee16 (Aug 21, 2010)

Umbran said:


> Well, they don't have to worry directly about the water itself.  But there's climate change associated with that.  And, when NYC, London, Hong Kong, and several other major metropolitan/financial centers take the swim, the world economy collapses.  And every single port in the world is inundated - so no more petroleum shipments...
> 
> It's all interconnected.




Yes, I'm familiar with that.  What I was asking was simply about the straight facts of whether particular areas would experience flooding.  Like, if an inland city, 3000km from the ocean, but on the side of a river, and hence only 60m above sea level would itself be 20m under water if the sea levels rose by 80m.

Sorry for not making my question more clear.

I definitely understand that such a scenario would have disastrous effects from an environmental and financial standpoint.  We'd be crowding a lot of people into a smaller amount of arable terrain, among other things, and plenty of the places in the middle of North America are rather arid and dry, and, from what I understand, don't really have the potable water reserves to support the increased population levels they would have.

However.....I'm also not of the opinion that such a disaster is irrecoverable.  The planet is very resilient.  And life is very tenacious.  Even if, in the (geologically tiny scale) 2 million years following a disaster like that and a collapse of the ecosystem, the planet was not very well adapted for life with homo sapiens and current life forms, the survivors would adapt, and eventually flourish.  Of course, tough luck for humans, but that's evolution.

Earth's had disaster's wiping out 50-80% of life on the planet, and the result is often a boom in evolution and diversity after the fact.  Of course, if you're a species living right *before* the disaster, it sucks to be you.......but if you're alive *after* the disaster, there's tonnes of opportunity.

Banshee


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## Janx (Aug 21, 2010)

Banshee16 said:


> However.....I'm also not of the opinion that such a disaster is irrecoverable.  The planet is very resilient.  And life is very tenacious.  Even if, in the (geologically tiny scale) 2 million years following a disaster like that and a collapse of the ecosystem, the planet was not very well adapted for life with homo sapiens and current life forms, the survivors would adapt, and eventually flourish.  Of course, tough luck for humans, but that's evolution.
> 
> Earth's had disaster's wiping out 50-80% of life on the planet, and the result is often a boom in evolution and diversity after the fact.  Of course, if you're a species living right *before* the disaster, it sucks to be you.......but if you're alive *after* the disaster, there's tonnes of opportunity.
> 
> Banshee




why would you assume that we humans wouldn't survive an environmental change where other animals would?

Humans are responsible for changing the environment on local scales that cause species to die out.  That's how fragile other species are.

Humans are found living in cold climates where it gets -40 degrees F or colder (I know, I lived in such a place), and in places it gets to be 110 F or worse, like Iraq.

Frankly, we're better suited for change than most other lifeforms on this planet.  We got brains to relocate, build shelter or adapt.

Unless the planet becomes truly incompatible to life, I suspect there will be humans surviving an environmental disaster.

That doesn't mean folks won't die, just that there will still be plenty of survivors.


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## jonesy (Aug 21, 2010)

Janx said:


> Humans are found living in cold climates where it gets -40 degrees F or colder (I know, I lived in such a place).



You've lived in Finland? We hit -37,1 last winter. It was pretty chilly.


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## El Mahdi (Aug 21, 2010)

Banshee16 said:


> ...I definitely understand that such a scenario would have disastrous effects from an environmental and financial standpoint. We'd be crowding a lot of people into a smaller amount of arable terrain, among other things, and plenty of the places in the middle of North America are rather arid and dry, and, from what I understand, don't really have the potable water reserves to support the increased population levels they would have...




Maybe disastrous, maybe not.  It's truly impossible to model what the exact impact would be.  Of course it's easy to model rising sea-level.  Fairly simple for the short term, you just look at elevation.  Though over the long term it's a bit more difficult (long term meaning thousands of years) as land masses will actually rise in elevation due to loss of glaciers and ice caps weighing them down.

But the big kicker is that we can only conjecture as to how a rising sea level will affect weather patterns.  It could be quite possible that places considered arid now, could see significant increases in precipitation.  Imagine the possibility of the Sahara Desert returned back to it's former savanah-like environment.  We just can't accurately model it well enough.  Of course there are those out there who say they can model it, and of those number of people there's an almost equal number of differing opinions and conclusions.


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## Umbran (Aug 22, 2010)

Banshee16 said:


> However.....I'm also not of the opinion that such a disaster is irrecoverable.




Yes, life is resilient.  That's nice, but it cold comfort if your own species buys the farm.


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## Banshee16 (Aug 24, 2010)

Janx said:


> why would you assume that we humans wouldn't survive an environmental change where other animals would?
> 
> Humans are responsible for changing the environment on local scales that cause species to die out.  That's how fragile other species are.
> 
> ...




I'd never predict that such an event would kill every human.  I think however, that civilization as we know it would change significantly....and populations might be severely curtailed.  But even if 99% of humans were killed, that still leaves 70 million....more than enough to continue the species.  Enough to continue modern civilization?  Maybe not....at least in the short term.

But I will point out that despite our brains, we're still living organisms, who on some level, obey the same physical and biological laws as other life forms.  We need access to clean water, we need food, though we can survive without it.  When supplies run out or become scarce, civil society can and does break down.  We saw during the Ice Storm, supposedly in the aftermath of Katrina, etc.  Now, imagine the chaos caused by displacing tens of millions of people into areas that weren't built up to support them.

I could be wrong, but I think the problem is more on the level of......if changes like this cause problems that disrupt our food supply even on a relatively short-term level, like one or two years, imagine how many people could suffer or die during that time.  It's not inconceivable.  Plants can adapt and grow back.....but look how long it takes.  I remember near my cottage, they clear cut part of the forest.....15 years ago.  Basically down to ferns.  It's been allowed to grow back, but it has to go through the natural cycle.  Now, there are poplars, some conifers coming back etc....but it's still nowhere near where it was, and it's going to be another fifty years before it recovers to that point.

I don't think anyone can predict what would happen....but I think it's arrogant of humans to assume that just because we're human, we will.  I think our brains and the sheer number of us on the planet give us better than even chances, but who knows?

Banshee





Banshee


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## jonesy (Aug 24, 2010)

Banshee16 said:


> ....but I think it's arrogant of humans to assume that just because we're human, we will.  I think our brains and the sheer number of us on the planet give us better than even chances, but who knows?



I once saw someone with a great sarcastic t-shirt.

On the front it said "What Would The Dinosaurs Have Done?".

On the back was a meteor hitting Earth.


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## Umbran (Aug 24, 2010)

Janx said:


> why would you assume that we humans wouldn't survive an environmental change where other animals would?




Because, honestly, in the middle of such drastic changes, it isn't really "survival of the fittest".  It's more survival of the lucky.  In such disasters, it isn't just competition within your accustomed niche.  It's a question of whether or not your niche gets ripped out from under you.  In a mass-extinction event, nobody, and I mean nobody, gets a free pass.

We humans are typically adaptable if we get to plan, and work together.  Drop an unprepared human into a harsh situation and he or she usually dies pretty quickly.  We are not well protected against the elements (cold or hot, wet or dry).  We are not strong, we are not fast.  We are tool using monkeys, but most of us _don't know how to make tools anymore_.


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## jonesy (Aug 24, 2010)

Umbran said:


> Because, honestly, in the middle of such drastic changes, it isn't really "survival of the fittest".



It kind of is, but the term was always a bit of a misnomer. It should be called "survival of those best suited, prepared and placed to live through all particular situations they will experience in their lifetime". In other words, lucky enough to be exactly what, who, and where the situations require you to be to survive. 

If a meteor hits Eurasia and kills everyone there, one would be lucky to have the attribute "american".


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## Umbran (Aug 24, 2010)

jonesy said:


> If a meteor hits Eurasia and kills everyone there, one would be lucky to have the attribute "american".




Part of the point is that if a meteor hits Eurasia and kills everyone there, being in the Americas won't save you.  Mass extinction events have global, not local. Once you get over a certain scale, everything is connected, one large system, not several isolated ones.  

Basically, it isn't so much a question of who survives, but who doesn't die.  If I have six people, and a revolver with five bullets, and we play a modified Russian Roulette, it is not "fitness" to be the one who lives.  There's nothing about your design and makeup that makes you the survivor.


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## jonesy (Aug 24, 2010)

Umbran said:


> Basically, it isn't so much a question of who survives, but who doesn't die.  If I have six people, and a revolver with five bullets, and we play a modified Russian Roulette, it is not "fitness" to be the one who lives.  There's nothing about your design and makeup that makes you the survivor.



That again depends on how one defines it. If you are the kind of person who likes standing on the left side of the room, and the empty chamber happens to end up handed to the person on the left side of the room, which is you, then your tendency to be at the right spot saves you.

Even if the chamber is re-rolled every time, and the gun is handed to the next person randomly, it's still your placement in the space time continuum which saves you.

It's lucky, because it's not something you trained for, but it is a part of what you are, because of where who you are ends up taking you.

Which ends with the question of whether your makeup defines where you end up in space time, or whether makeup of space time ends you where you go. Or whether it really is all random.

At the atomic level cause and effect seem to pre-determine a lot, while at the quantum level cause and effect don't seem to get along very well. How this makes any sense, I have no idea.


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## El Mahdi (Aug 24, 2010)

Umbran said:


> ...Basically, it isn't so much a question of who survives, but who doesn't die. If I have six people, and a revolver with five bullets, and we play a modified Russian Roulette, it is not "fitness" to be the one who lives. There's nothing about your design and makeup that makes you the survivor.




..and when it's my turn, instead of accepting the premise of the situation and submitting to random chance, I can take the gun and start shooting the other four, or simply throw the gun away...

If one allows their self to be _completely_ at the whim of random chance, you're right. However, those who prepare may have an increased chance. Luck may be the biggest factor, maybe even the dominant factor by magnitudes, but it's not the only one...


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## Umbran (Aug 24, 2010)

El Mahdi said:


> If one allows their self to be _completely_ at the whim of random chance, you're right.




You speak as if you have an option to be otherwise.  

On the species-scale, if and when you can make an argument that humanity is trying to take control of the gun, or somesuch, then maybe you'll have a point.  Right now, I think you'd be hard pressed to demonstrate that we're doing anything other than trying to shove a sixth bullet into the chamber.

As for individuals, there's a very simple problem of not being able to predict what the circumstances will be, leading to an inability to prepare.  Do you prepare for ice-age conditions, or heat and decade-long drought?  Are you going to need to be far inland, to avoid rising seas, or will you need to be near shore to get rain and seafood resources?  What kinds of plants (if any) will grow in your new environs?  What kind of animals can you keep?  You don't know, and unless you're Bill Gates you probably don't have the resources to prepare for _everything_.  

If you cannot prepare for everything, you have to guess, and we are back to roulette, rather than fitness.

And that's ignoring the usual risk-assessment issue of spending resources preparing for low-probability events - which generally turns out to be a dumb idea.


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## Banshee16 (Aug 25, 2010)

Umbran said:


> We are not strong, we are not fast.  We are tool using monkeys, but most of us _don't know how to make tools anymore_.




This is a very good point.  This is something I was thinking of during this discussion.

In addition, we, like any other animal, are adapted to live in certain conditions.  Looking at what's happening/happened in Moscow in August, a lot of people died, and one of the things it came down to was air clarity....and...temperature.  When temperatures get over a certain level, people can't cope.  The weak die.  We're just not biologically adapted to live in certain conditions.

There are many people who likely wouldn't survive if the food supply system broke down for instance.  And, in certain parts of the world, (like most of my country) many people would die if we had extended power outages in the heart of winter.....not just days.....but months.  Not that humans can't survive in cold climates.  The Inuit show us that they can.  But not everybody has their knowledge.

What percentage of people could start a fire?  Given matches?  What about with sticks?  Or by banging rocks together?  What percentage of people still likely know how to make snares, or proper lean-to's or any number of things in survival conditions?  Geeze, I know enough people who can't even tell the cardinal directions of the compass.

As a society, we have lots of information at our fingertips, but I think that the specialized training so many of us receive in order to fill our specific roles in society means that general knowledge that might be important in situations where we didn't have our computers, transportation systems etc. goes by the wayside.

Of course, those who *do* possess these skills could always teach others in the event that it became necessary.  But could it be done in sufficient numbers quickly enough if there was a collapse?

Hopefully this never really becomes an issue.

Banshee


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## Banshee16 (Aug 25, 2010)

jonesy said:


> I once saw someone with a great sarcastic t-shirt.
> 
> On the front it said "What Would The Dinosaurs Have Done?".
> 
> On the back was a meteor hitting Earth.




Nice 

I haven't said any of this to say that I think the sky is falling.  More, that we don't know.  We can't predict what will happen.  It's vastly more likely that tomorrow, people will get up, have breakfast, go to work, go home, have dinner, and go to sleep.

But when we're talking about planet wide changes, major environmental modifications, meteor strikes etc. we *think* we have better than normal chances of surviving, but it's kind of like the guy smoking his cigarette saying that "I won't get sick from this, that'll just happen to someone else".  You really can't predict what nature has in mind, and we're very tiny, when it comes down to it.

People get weird diseases, they slip and fall, have strokes, heart attacks, get run over by drunk drivers, hit by stray bullets in gangland shootings.  A baby only a few weeks old was left parentless a few days ago, when her parents were with her in the family car, coming home from a wedding, and got hit by another vehicle.  Both parents dead.  No chance.  Baby survives.  Another family in my area years ago......were driving on a local two lane highway, and a tree falls on their car. Husband and child killed, wife survives.  Again, no warning, no chance, no choice.  Nothing to do with survival of the fittest....just pure, dumb, bad luck.

IMO, when your time is up, your time is up, and there's nothing you can do about it.....and that goes on an individual level, as well as a global or racial level.

That doesn't mean to just sit there like a bump, and not strive for anything....but it does mean to appreciate every day, because you're never sure if you'll have another.

Banshee


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## El Mahdi (Aug 28, 2010)

Umbran said:


> You speak as if you have an option to be otherwise.
> 
> ...
> 
> ...




Short of something that would turn the entire planet into a bubbling ball of magma (like when the moon was created), I do think there are options (which have been explored quite extensively in sci-fi - most in a laughable manner, but some quite seriously).  So yes, even as an individual, I do believe there are things one can do to change the odds and remove oneself (or at least _attempt_ to remove oneself) from the game.  No matter how impractical they may be, or may _appear_, there are still things that _can_ be done...even by individuals.



Umbran said:


> On the species-scale, if and when you can make an argument that humanity is trying to take control of the gun, or somesuch, then maybe you'll have a point. Right now, I think you'd be hard pressed to demonstrate that we're doing anything other than trying to shove a sixth bullet into the chamber. ...




I _do_ have a point...because I agree with you (on this anyways).

But, it doesn't change the point that we (humanity) are only in this game of Russian Roulette, because we _choose_ to be.  We have the ability to do something about it, and _choose_ not to (currently).

I like your analogy of doing our best to shove a sixth bullet in the chamber.  That's exactly what I think we've done by cancelling the Constellation program.  Hopefully we won't remain so shortsighted forever.  I wouldn't necessarily be happy if another country picked up the torch and carried it instead of us, but it would be better than doing nothing (as a species).


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## jonesy (Aug 29, 2010)

El Mahdi said:


> I wouldn't necessarily be happy if another country picked up the torch and carried it instead of us, but it would be better than doing nothing (as a species).



Not to be snarky or anything, but the post-soviet-russian space missions kind of did that already while your shuttles were grounded. What I think we need now is russian ruggedness with internationally designed and tested parts with american production capability. Best of everything instead of lowest bidder.


Edit: you know, sarcasm really is hard to detect on the Internet. I'm looking at what I wrote and I can't decide myself what that actually means. And when the sentence begins with 'not to be snarky or anything' you should always get a bit suspicious. 

Don't mind me. I'm a goofball.


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## El Mahdi (Aug 29, 2010)

jonesy said:


> Not to be snarky or anything, but the post-soviet-russian space missions kind of did that already while your shuttles were grounded. What I think we need now is russian ruggedness with internationally designed and tested parts with american production capability. Best of everything instead of lowest bidder.
> 
> 
> Edit: you know, sarcasm really is hard to detect on the Internet. I'm looking at what I wrote and I can't decide myself what that actually means. And when the sentence begins with 'not to be snarky or anything' you should always get a bit suspicious.
> ...




I'd insert a "suspicious" smiley here...if we had one...

Yeah, it looks like we are going to be relying on the Russians and, possibly, private companies for the near future.  But that's really just for orbital stuff (satelites, ISS, etc.).  I don't know if there's really any programs working toward something like going to Mars.  Although I do think there are a couple trying to work toward going to the moon.

But you're probably right.  Any real future successes will probably need to be International contributions.


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## TanisFrey (Aug 30, 2010)

I agree with the need to try to bring private companies into doing the heavy lifting BUT, we need a real manned program until they can do it.  We need to continue the US ability to lunch men into space, even if we do it by building new shuttles.


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## Someone (Aug 31, 2010)

TanisFrey said:


> We need to continue the US ability to *lunch* men into space.




Nyarlathotep needs food badly!


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## jonesy (Aug 31, 2010)

Someone said:


> TanisFrey said:
> 
> 
> > We need to continue the US ability to lunch men into space.
> ...



Another good reason why we need to get off this rock and out into the loving arms of Azathoth.. oh, wait..


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## TanisFrey (Sep 1, 2010)

TanisFrey said:


> I agree with the need to try to bring private companies into doing the heavy lifting BUT, we need a real manned program until they can do it.  We need to continue the US ability to lunch men into space, even if we do it by building new shuttles.






Someone said:


> Nyarlathotep needs food badly!






jonesy said:


> Another good reason why we need to get off this rock and out into the loving arms of Azathoth.. oh, wait..




ROFLOL, that teaches me not to post without reading what I typed.


Rewrite:
We need to continue the US ability to launch men into space, even if we do it by building new shuttles.


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## ssampier (Sep 6, 2010)

Would I survive in a post apocalyptic environment?

I am going to say no. Sad--and slightly depressing--to say so.

My only appreciable skill is computers and fixing them. That skill would not very useful in a eat-or-be-eaten environment. My glasses and allergies would probably be a disadvantage, as well.



jonesy said:


> Another good reason why we need to get off this rock and out into the loving arms of Azathoth.. oh, wait..




Who will be eaten first?


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## jonesy (Sep 7, 2010)

On the tangent of finding stuff in space here's something incredible, and beautiful. Hubble found a star which has turned into a *1/3 lightyear wide carbon sprinkler*:

Awesome death spiral of a bizarre star - Discover Magazine


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## Pbartender (Sep 8, 2010)

In other news...

Two asteroids to pass close to Earth on Wednesday – This Just In - CNN.com Blogs


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## El Mahdi (Sep 8, 2010)

ssampier said:


> Would I survive in a post apocalyptic environment?
> 
> I am going to say no. Sad--and slightly depressing--to say so.
> 
> My only appreciable skill is computers and fixing them. That skill would not very useful in a eat-or-be-eaten environment...




That's not necessarily true.  Your only appreciable skill is _not_ simply repair and operation of computers, it's the core skills that make you able to do that.  Those skills can help you survive.

At the top of the list, you have the ability to visualize or conceptualize a complex system.  You are also able to prioritize problems and troubleshoot problems.  You also must have at least average dexterity (although probably slightly above average due to some of the finer work required).

These are all core skills that directly translate to things like hunting and combat, and solving problems of survival (building a shelter, finding water, etc.).

The only real question is whether you could mentally adapt to a new paradigm.  You have the skills, you can learn the knowledge, but can you make the mental shift...

I think you might surprise yourself with what you're capable of.


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## El Mahdi (Sep 8, 2010)

Pbartender said:


> In other news...
> 
> Two asteroids to pass close to Earth on Wednesday – This Just In - CNN.com Blogs




Gee, Thanks!  Now my Wednesday is just shot to hell!


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## Orius (Sep 9, 2010)

Those rocks really aren't that big though.


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## Umbran (Sep 9, 2010)

Orius said:


> Those rocks really aren't that big though.




No?  

A rock 5 to 10 meters across entering the atmosphere has about as much energy as Little Boy, the atomic bomb they dropped on Hiroshima.  About one such rock comes along each year, and usually they burn up on the way in.  It doesn't threaten Life On Earth(TM), but the thing is still the size of a house, and you probably wouldn't want it landing in your back yard.


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## Pbartender (Sep 9, 2010)

Umbran said:


> No?
> 
> A rock 5 to 10 meters across entering the atmosphere has about as much energy as Little Boy, the atomic bomb they dropped on Hiroshima.  About one such rock comes along each year, and usually they burn up on the way in.  It doesn't threaten Life On Earth(TM), but the thing is still the size of a house, and you probably wouldn't want it landing in your back yard.




Right...  It'd still be like a small Tunguska impact.


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## TanisFrey (Sep 9, 2010)

Pbartender said:


> Right...  It'd still be like a small Tunguska impact.



Which leveled all the trees in the area, it knocked over an estimated 80 million trees over 830 sq mi area.  Lucky, no one lived there.


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