02-23-2017, 03:42 PM
You've probably all seen this already — researchers this week announced the finding of four more Earth-sized planets in the TRAPPIST-1 solar system, about 40 light years from here. That brings the total to seven; three of these are clearly in the habitable zone, and all seven might have liquid water in some locations, depending on their atmospheres.
![[Image: 230217_trappist_1a.jpg?fit=clip&w=835]](https://cosmos-magazine.imgix.net/file/spina/photo/9696/230217_trappist_1a.jpg?fit=clip&w=835)
TRAPPIST-1 is a dwarf star, like most of the stars in the galaxy. That means these planets orbit very close, with orbital periods all under 13 Earth days. They're almost certainly tidally locked to the star, with one side always facing the sun and the other side always dark. And, such close-in planets tend to lose their atmospheres, unless they happen to have a very strong magnetic field.
But still. We keep turning up more and more of these Earth-sized planets at the right distance from their suns to have liquid water. If these planets don't have life already, they could probably be terraformed to support Earth life without too much trouble (by the time we'd be able to get to them anyway).
Of course, by the time we can get to even Alpha Centauri, we won't need planets to live on anymore — most of humanity will be living in thousands (millions?) of orbital space colonies, throughout the solar system. Planets will seem passé.
But... The bigger an ecosystem is, the more stable it is. Space colonies will require active maintenance, and if some disaster ever strikes down all the people, the plants and animals won't survive long without them. That's an extremely unlikely scenario, I know, but still... there's something viscerally appealing about seeding the galaxy with rich ecosystems, wherever we find a planet that's habitable (or can be made habitable) and not already alive. These living green planets could act as reservoirs of life that could even outlast humanity, possibly evolving new civilizations someday.
Or maybe I'm just dreaming. What do you think?
TRAPPIST-1 is a dwarf star, like most of the stars in the galaxy. That means these planets orbit very close, with orbital periods all under 13 Earth days. They're almost certainly tidally locked to the star, with one side always facing the sun and the other side always dark. And, such close-in planets tend to lose their atmospheres, unless they happen to have a very strong magnetic field.
But still. We keep turning up more and more of these Earth-sized planets at the right distance from their suns to have liquid water. If these planets don't have life already, they could probably be terraformed to support Earth life without too much trouble (by the time we'd be able to get to them anyway).
Of course, by the time we can get to even Alpha Centauri, we won't need planets to live on anymore — most of humanity will be living in thousands (millions?) of orbital space colonies, throughout the solar system. Planets will seem passé.
But... The bigger an ecosystem is, the more stable it is. Space colonies will require active maintenance, and if some disaster ever strikes down all the people, the plants and animals won't survive long without them. That's an extremely unlikely scenario, I know, but still... there's something viscerally appealing about seeding the galaxy with rich ecosystems, wherever we find a planet that's habitable (or can be made habitable) and not already alive. These living green planets could act as reservoirs of life that could even outlast humanity, possibly evolving new civilizations someday.
Or maybe I'm just dreaming. What do you think?
Joe Strout
Lead Developer, High Frontier