Okay, putting my own view on this - lot's of varying opinions of course, don't think an "objective answer" is possible, we just don't know enough - particularly about how future technology will develop, or what we will want to do a few centuries from now.
So - first of all the broader picture - there is nothing in the next few hundred million years likely to make Earth as bad a place to colonize as Mars or Venus.
So - not much point in leaving Earth to look for somewhere better until then.
If we try to terraform Mars now - first of all - not at all clear that we know enough to do it - lots to go wrong. Also, terraforming isn't practical in less than a thousand years or so, most likely tens or hundreds of thousands of years - this is the estimate of the Mars society so presumably erring more towards the optimistic. On Earth of course, it took millions of years, and Mars is not sufficiently Earth like to use same methods - move Earth out to Mars and it would turn into a snowball planet.
For many things that could go wrong, see Trouble With Terraforming Mars
But also - won't help with this long term issue - because our ideas for terraforming Mars are only temporary. If they work, a big if, then the result is not stable long term because of the low gravity, lack of continental drift, and the lack of a protecting magnetic field. Again the Mars Society acknowledge this, they are not aiming to terraform Mars permanently - probably not even for millions of years - but just for many thousands of years.
It's hard to say how long a terraformed Mars would last. It might simply unterraform as quickly as it was terraformed if done in a way that is not based on a good understanding of how planets work long term.
It might well end up worse than it is now, hazardous for humans in various ways. .
If it lasts longer than that, then long term effects include
That's a timescale long enough to evolve from this:
Tarsier
all the way to humans many times over. Indeed it is long enough to evolve from the first ever complex multicellular lifeforms (Cambrian explosion 542 million years ago) to humans.
It's verging on absurd to suppose we can do things to Mars now that will be of benefit to whatever species inhabits Earth so far into the future - and that we know what it is they will want and how best to prepare for their wishes right now.
So - I think colonizing Mars or attempting to terraform it can't help at all with issues of future extinction of life on Earth.
Won't be humans anyway - but idea that we should act now to help prevent future extinction of whatever species on Earth exists by the time we do face a threat that is a threat to life on Earth and human survival on Earth - that I think borders on the absurd - with present technology.
Though - we could make things harder for them if we so spoil Mars that it is no longer available to them as a temporary refuge when they need it. With mega-techynology e.g. self replicating machines we could do more, even reshape the entire solar system - move planets around, even make "Dyson clouds" etc - and maybe in that future could also build large scale self - perpetuating systems that last for billions of years with only automatic self maintenance for future beings to use - but are not yet at the point where we need to make decisions about such things.
As for colonizing for other reasons though - that we might do.
I think it's possible. But not by colonizing other planets, instead by creating habitats in space. As you say, we can't step outside of our spacesuits anywhere in near future, or even far future for centuries.
You could create large domed cities on a planet - but then what about cosmic radiation? You need to cover the dome with several meters of regolith - or some other substance to block it.
That's easier done in free space, because then you can enclose a large area easily, with the shielding at floor level - mirrors to bring in sunlight - and artificial gravity through spinning - and whatever weather and temperature you like, usually the thing is to dissipate heat in space - so would be a case of controlling the dissipation to get the temperature you want.
If you could make habitats like that which are also easy to maintain, so you don't spend all your time just patching it - then building and living inside would be as easy as living on the Earth in the tropics, or whatever your favourite climate is.
And there's plenty of material in space to do it, Asteroid Resources Could Create Space Habs For Trillions; Land Area Of A Thousand Earths
But then - I also wonder if we can or should do it. First of all in near future, is hard to see it working peacefully - and war in space seems totally impossible, because the habitats are so vulnerable to impacts at speeds easily achieve din space. Are we mature enough to have trillions of people living in space in habitats that are so fragile that any of the colonies could easily take out all the others if it went to war? So any war would be a case of MAD?
In far future - what happens to the galaxy if we let our species loose on it, not just our solar system but entire galaxy? What would we evolve into? What would our descendants create by way of self replicating machines (probably just a few decades into the future if we get nanoscale 3D printed computer chips), constructing new life forms from scratch and so on. Any of those could potentially start to spread and colonize the galaxy - with humans perhaps with ideas we find crazy - or with self replicating machines that someone made - or with new biological creatures invented and created by future humans? Or new XNA based life - different biology from DNA?
And what happens when those come back to Earth at some future date? What happens to any other ETs in the galaxy if all this happens? They may be advanced as a civilization - but many possibilities for ETs to be civilized but non technological and a highly advanced, even millions or billions of years old civilization, without our technology, might not last long if one of our machines, or even DNA or XNA from Earth gets to it.
I see it working in one scenario - if we only explore the galaxy for the most part rather than colonize it - with a small number of colonies in space that doesn't grow exponentially to fill the galaxy -- and develop into a far more peaceful species that looks into the far future.
But if that is the solution - not too clear how we get to there from here.
One idea, just possibly might work, I don't know, perhaps populations of ETs in a galaxy don't have to grow exponentially - there's sign of that here - we already have peak child on Earth, happened a few years ago - the population is growing as people get to live longer, but we have no more children than we had a few years back (not clear this is going to continue, if it is a peak, or just a short term hump, but might be).
However on the plus side. We do seem to be able to solve many issues eventually. So far already learned to live with:
If we'd had only, say, 20 years to fix all that instead of a century - I think the world would be in far more of a disaster than it is now.
So, I'm hopeful that it can be got to work, but time is on our side, so I think the question really is - not so much - can we do it - as - can it happen slowly enough, can we be forward looking enough - to be able to adjust to it in time and to find solutions?
Personally I think the key to doing that is to go into space to explore and to gain new knowledge, and to help solve problems on the Earth, rather than to colonize. It's too soon to go into space for sake of colonization for it's own sake. But if we recognize how little we know and understand so far, and go into space mainly for knowledge - and to help the Earth - I think then we have a chance.
Though it may seem it is taking for ever and some people are really impatient to see us become a multi-planet species - or a species not tied down to the Earth - I don't think that really is our priority right now.
Because - in any case we don't face any natural disasters likely to destroy all of humanity - even a giant meteor strike would leave many survivors. But we could destroy ourselves.
So, setting up huge powerful colonies in space of trillions of people with space technology - if they are able to build Stanford Torus habitats - and to mine the asteroid belt for instance - hat might well be the most dangerous thing we could do for our civilization - if we do it too soon when we don't understand things too well and haven't had time to adjust.
Smaller colonies, with focus on helping the Earth, and exploration - that might be the best way to do it right now. Then - perhaps we have a chance - and at least have a bit more time to find solutions to the situations that we might need to face if we do have trillions in space - and have capability to colonize the galaxy.
I've written a fair number of articles now exploring these ideas, two others not yet mentioned:
So - first of all the broader picture - there is nothing in the next few hundred million years likely to make Earth as bad a place to colonize as Mars or Venus.
So - not much point in leaving Earth to look for somewhere better until then.
If we try to terraform Mars now - first of all - not at all clear that we know enough to do it - lots to go wrong. Also, terraforming isn't practical in less than a thousand years or so, most likely tens or hundreds of thousands of years - this is the estimate of the Mars society so presumably erring more towards the optimistic. On Earth of course, it took millions of years, and Mars is not sufficiently Earth like to use same methods - move Earth out to Mars and it would turn into a snowball planet.
For many things that could go wrong, see Trouble With Terraforming Mars
But also - won't help with this long term issue - because our ideas for terraforming Mars are only temporary. If they work, a big if, then the result is not stable long term because of the low gravity, lack of continental drift, and the lack of a protecting magnetic field. Again the Mars Society acknowledge this, they are not aiming to terraform Mars permanently - probably not even for millions of years - but just for many thousands of years.
It's hard to say how long a terraformed Mars would last. It might simply unterraform as quickly as it was terraformed if done in a way that is not based on a good understanding of how planets work long term.
It might well end up worse than it is now, hazardous for humans in various ways. .
If it lasts longer than that, then long term effects include
- Loss of water from the upper atmosphere as it splits into hydrogen and oxygen and the hydrogen escapes - no magentic field to prevent the solar wind stripping the atmosphere
- CO2 dissolving in the shallow seas forming limestone - with no continental drift then there is nothing to return it to the atmosphere
- Mars just cools down. To stay warm enough you need greenhouse gas factories, or giant mirrors in space - or both. If the beings on future Mars either don't know or have lost the capability to maintain this technology then Mars cools down and becomes a snowball Mars
That's a timescale long enough to evolve from this:
Tarsier
all the way to humans many times over. Indeed it is long enough to evolve from the first ever complex multicellular lifeforms (Cambrian explosion 542 million years ago) to humans.
It's verging on absurd to suppose we can do things to Mars now that will be of benefit to whatever species inhabits Earth so far into the future - and that we know what it is they will want and how best to prepare for their wishes right now.
So - I think colonizing Mars or attempting to terraform it can't help at all with issues of future extinction of life on Earth.
Won't be humans anyway - but idea that we should act now to help prevent future extinction of whatever species on Earth exists by the time we do face a threat that is a threat to life on Earth and human survival on Earth - that I think borders on the absurd - with present technology.
Though - we could make things harder for them if we so spoil Mars that it is no longer available to them as a temporary refuge when they need it. With mega-techynology e.g. self replicating machines we could do more, even reshape the entire solar system - move planets around, even make "Dyson clouds" etc - and maybe in that future could also build large scale self - perpetuating systems that last for billions of years with only automatic self maintenance for future beings to use - but are not yet at the point where we need to make decisions about such things.
As for colonizing for other reasons though - that we might do.
I think it's possible. But not by colonizing other planets, instead by creating habitats in space. As you say, we can't step outside of our spacesuits anywhere in near future, or even far future for centuries.
You could create large domed cities on a planet - but then what about cosmic radiation? You need to cover the dome with several meters of regolith - or some other substance to block it.
That's easier done in free space, because then you can enclose a large area easily, with the shielding at floor level - mirrors to bring in sunlight - and artificial gravity through spinning - and whatever weather and temperature you like, usually the thing is to dissipate heat in space - so would be a case of controlling the dissipation to get the temperature you want.
If you could make habitats like that which are also easy to maintain, so you don't spend all your time just patching it - then building and living inside would be as easy as living on the Earth in the tropics, or whatever your favourite climate is.
And there's plenty of material in space to do it, Asteroid Resources Could Create Space Habs For Trillions; Land Area Of A Thousand Earths
But then - I also wonder if we can or should do it. First of all in near future, is hard to see it working peacefully - and war in space seems totally impossible, because the habitats are so vulnerable to impacts at speeds easily achieve din space. Are we mature enough to have trillions of people living in space in habitats that are so fragile that any of the colonies could easily take out all the others if it went to war? So any war would be a case of MAD?
In far future - what happens to the galaxy if we let our species loose on it, not just our solar system but entire galaxy? What would we evolve into? What would our descendants create by way of self replicating machines (probably just a few decades into the future if we get nanoscale 3D printed computer chips), constructing new life forms from scratch and so on. Any of those could potentially start to spread and colonize the galaxy - with humans perhaps with ideas we find crazy - or with self replicating machines that someone made - or with new biological creatures invented and created by future humans? Or new XNA based life - different biology from DNA?
And what happens when those come back to Earth at some future date? What happens to any other ETs in the galaxy if all this happens? They may be advanced as a civilization - but many possibilities for ETs to be civilized but non technological and a highly advanced, even millions or billions of years old civilization, without our technology, might not last long if one of our machines, or even DNA or XNA from Earth gets to it.
I see it working in one scenario - if we only explore the galaxy for the most part rather than colonize it - with a small number of colonies in space that doesn't grow exponentially to fill the galaxy -- and develop into a far more peaceful species that looks into the far future.
But if that is the solution - not too clear how we get to there from here.
One idea, just possibly might work, I don't know, perhaps populations of ETs in a galaxy don't have to grow exponentially - there's sign of that here - we already have peak child on Earth, happened a few years ago - the population is growing as people get to live longer, but we have no more children than we had a few years back (not clear this is going to continue, if it is a peak, or just a short term hump, but might be).
However on the plus side. We do seem to be able to solve many issues eventually. So far already learned to live with:
- Chemical weapons
- Nuclear weapons
- Jet engines - imagine if planes as fast as that existed in WWII
- Depletion of ozone layer
- DDT problems of "silent spring"
- Developed good working treaties such as the Antarctic Treaty - Nuclear Test Ban Treaty - and the Outer Space Treaty - which for the most part are actually working.
- Faced prospect of mass starvation world wide and prevented it with the Green Revolution (often forgotten about now)
- Facing up to extinctions of species - though there are still many extinctions, are doing something about it.
- Problems caused by introducing new species into environments not used to them.
If we'd had only, say, 20 years to fix all that instead of a century - I think the world would be in far more of a disaster than it is now.
So, I'm hopeful that it can be got to work, but time is on our side, so I think the question really is - not so much - can we do it - as - can it happen slowly enough, can we be forward looking enough - to be able to adjust to it in time and to find solutions?
Personally I think the key to doing that is to go into space to explore and to gain new knowledge, and to help solve problems on the Earth, rather than to colonize. It's too soon to go into space for sake of colonization for it's own sake. But if we recognize how little we know and understand so far, and go into space mainly for knowledge - and to help the Earth - I think then we have a chance.
Though it may seem it is taking for ever and some people are really impatient to see us become a multi-planet species - or a species not tied down to the Earth - I don't think that really is our priority right now.
Because - in any case we don't face any natural disasters likely to destroy all of humanity - even a giant meteor strike would leave many survivors. But we could destroy ourselves.
So, setting up huge powerful colonies in space of trillions of people with space technology - if they are able to build Stanford Torus habitats - and to mine the asteroid belt for instance - hat might well be the most dangerous thing we could do for our civilization - if we do it too soon when we don't understand things too well and haven't had time to adjust.
Smaller colonies, with focus on helping the Earth, and exploration - that might be the best way to do it right now. Then - perhaps we have a chance - and at least have a bit more time to find solutions to the situations that we might need to face if we do have trillions in space - and have capability to colonize the galaxy.
I've written a fair number of articles now exploring these ideas, two others not yet mentioned:
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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