5 replies to this topic

[CultureClash]

In your timeline you present humans major expansion into space as being the terraforming of mars and Venus,
with asteroid mining as being something that really takes off AFTER we begin to colonise and terraform these
planets.

I take issue with this.

While transhumanist technologies and attitudes would enable people to adapt to a wider range of environments
than we can at the present (including differing levels of gravity) it is still likely to be greatly beneficial for near (ish)
future habitats for humans and transhumans to be as similar as possible to earth.

While Venus has roughly the same gravity it has a hopelessly long day night cycle which would make trying to
terraform it exceedingly difficult.
Mars however has a similar day period to the earth but has much lower surface gravity.

This means that even after spending huge amounts of time and effort (a century to terraform mars is probably hopelessly
optimistic) neither would be close enough to earth that significant trans adaptations wouldn't be needed AND we only gain
something like an extra 1 1/2 times the earth worth of extra land area.

Given that optimum carrying capacity for the earth (particularly if you think we should heal it back to a pre-industrial state)
is probably around 1~2 billion then the total carrying capacity at that level for earth Venus and mars would optimistically be
5 billion (25 billion if you populate up to 10 billion per earth surface area). We already have 7 billion people with predictions
currently levelling off at 9~15 (ave ~10) billion.

After centuries of terraforming what you have to conclude is that you still don't get enough space for all the people alive now
let alone the population level we are expecting to reach.


However, terraforming planets isn't the only (or best) option.

Artificial space habitats;
like these...
http://visions2200.c...aceHabitat.html
http://en.wikipedia....i/Space_habitat

can be built to exactly mimic earth conditions including day length, gravity (simulated via rotation), and climate (with amount
of sunlight controlled by mirror size and orientation enabling construction outside of the 'habitable zone').
And due to being much smaller in area can be constructed and fully terraformed in decades rather than centuries.

Other advantages include low gravitational fields, meaning that travelling from one habitat to another is not inhibited by the
huge efforts required to lift yourself out of a planets gravity well.

Also terraforming asteroids by turning them into habitats can be done in parallel with asteroid mining, which means you can
be making a significant profit from mining and selling the valuable ore from these asteroids before you finish construction and
terraforming of the habitat making the initial cost barriers and time to return much less of an obstacle than terraforming a planet.

And finally, Nasa scientists have conservatively estimated that even without taking materiel from the Oort cloud or Keiper belt
there is enough materiel in the solar system in asteroids and such to house 1 Trillion people.

In short, Terraforming planets is likely to be more of an afterthought than the primary method of space colonisation.

As a side note, what this means for moving out of our solar system is that we don't need to limit ourselves to solar systems with
planets in habitable zones around stars.

Any solar system with a stable star and enough debris around it to enable habitat construction can be colonised.

For these reasons I think your timeline should be altered to recognise that the most likely path forwards is likely to massively
favour space colonisation via artificial space habitats rather than terraforming planets.

[Craven]

Space habitats are prone to disasters or malfunctions, terraformed planet should be more stable and sustainable. But yeah, our current technical level (not economical) allows for space habitat that should be self sustainable if given enough energy.

Another thing if we had technology to terraform planet, we'd probably be able to create space elevators, so leaving gravity well wouldn't be that hard. But this is all purely speculative.

[CultureClash]

Space habitats are prone to disasters or malfunctions, terraformed planet should be more stable and sustainable. But yeah, our current technical level (not economical) allows for space habitat that should be self sustainable if given enough energy.

Another thing if we had technology to terraform planet, we'd probably be able to create space elevators, so leaving gravity well wouldn't be that hard. But this is all purely speculative.

What disasters or malfunctions are habitats prone to?
And how can you know given nobody has yet built one?

Planets are also prone to disasters, earthquakes, volcanism, ect...

Space habitats are built from asteroid materiel, which means the biggest threat to them (being hit by another asteroid) is easily solved by anyone with the capability to build them. You clear the space they occupy from dangerous space debris when you construct them, as they are built from this debris.

Also space elevators wont work for every planet.
You couldn't build one on Venus for example as it rotates far to slowly.

And even where you can build a space elevator, it still takes energy to lift stuff up the elevator and then even when you have got up into space you still have to expend more energy to break orbit.

Space elevators also represent a bottleneck in the amount you can shift into space.
Proportionately you can get far more 'lift capacity per capita' from an artificial habitat than you can get from a planet with space elevators.

And none of this invalidates the point that space habitats can be made operational and ready for colonisation way faster than trying to terraform an entire planet.
which means you can start creating significant colonies of people in space much faster with artificial habitats than terraforming.
And that the total available space we can create with artificial habitats is something like 3 orders of magnitude larger than that we can create through planetary terraforming.


Also as a final point, there might well be a reluctance to terraforming from a 'conservation' perspective.
The planets of the solar system have had complex histories (which may in some cases include previous, or even current, existence of life) which would all be hidden and destroyed by any terraforming process. Also the appearance of those planets would be irrevocably altered by terraforming.
The 'red planet' would no longer be red...

So apart from practical concerns there might be considerable resistance to altering those planets to suite our needs when we can more easily get far more space by building habitats out of asteroids.

[Craven]

What disasters or malfunctions are habitats prone to?
And how can you know given nobody has yet built one?

All technology is prone to malfunctions, I don't need to build car to know it may be broken or fail at some point.

Planets are also prone to disasters, earthquakes, volcanism, ect...

Yeah but imagine extend of resources and space on planet. Even without terraforming one sustainable settlement may later lead to construction of other distant ones - bigger spread, bigger security and chance for survival.

Space habitats are built from asteroid materiel, which means the biggest threat to them (being hit by another asteroid) is easily solved by anyone with the capability to build them. You clear the space they occupy from dangerous space debris when you construct them, as they are built from this debris.

It ain't that easy. You need variety of elements to build hi-tech space habitat. One does not simply throw 3Dprinter into asteroid and wait for it to build everything from rock and iron.

And none of this invalidates the point that space habitats can be made operational and ready for colonisation way faster than trying to terraform an entire planet.

I didn't even suggest that invalidates that point. I even said that we currently have technology to build sustainable space habitat. That implied that we don't have technology to terraform Mars or Venus.

[CyberMisterBeauty]

Space habitats are prone to disasters or malfunctions, terraformed planet should be more stable and sustainable. But yeah, our current technical level (not economical) allows for space habitat that should be self sustainable if given enough energy.

Another thing if we had technology to terraform planet, we'd probably be able to create space elevators, so leaving gravity well wouldn't be that hard. But this is all purely speculative.

I don't think that,the space cities/stations are relatively secure on space because sideral space is a very calm place,and to avoid the disasters they will be surrounded by force fields,and they will be made by material that would be almost indestructible(carbon nanotubes,femtotech)



Space stations would be more stable,and if you want to go to a terraformed planet,just go to virtual reality.All food,water and other essential need will be solved by matter replication.

Edited by CyberMisterBeauty, 25 February 2012 - 06:28 PM.

[Logically Irrational]

I always thought that by the time humanity gets to the point where it can terraform a planet, it will have no need to from a societal standpoint. If it were to happen, it would probably be because "we can." If Venus Project-esque societies ever come into play, I could see humanity trying it for the thrill of creation and the technologies derived from the undertaking.

Space Habitats would totally be usefull though as far as expanding the population into deep space.