Colonizing other worlds

[Traab]

Something I was curious about. How precise are we when it comes to determining the viability of other worlds? By which i mean, its easy to determine the orbit of a planet is near earth in style, but can we determine the atmosphere around it? How about the likely average temp? After all, not every sun is the same so just because its orbiting at the same distance as we are doesnt mean the star its around is putting off the same energy. Its just, the idea struck me of basically creating generational ships meant to float off into the void in the general direction of planets we think could support life, with massive seed banks to try and plant whatever crops might survive on that world, and the materials needed to create a colony on hand but then I realized I didnt know how good we were at any of the aforementioned things so for all I know that "earth-like" planet is a ball of dead rock with no water, no air, and while it was CLOSE to earth in orbit, that still creates an average temp 50 degrees higher/lower than we have at best. And we wouldnt be able to tell all that till we basically reached the world in question.

What would it take to create a permanent colony on a world like that? Is it currently theoretically possible to create a sustainable atmosphere through something like say, sealed off domes? To have enough water for a permanent internal eco system of sorts? Assuming dead rock ball is about as good as it gets, but also as bad as it gets, meaning earth like gravity, the floor isnt lava, the air isnt acid, and the "seasons" are within tolerance levels.

[factotum]

Presumably you're talking about planets orbiting other stars here, in which case, we really don't know much about them at all. About all we can determine with reasonable accuracy is their mass and how far they orbit from their parent star. This doesn't really give us any idea what their composition is, what their atmosphere is like, or even what their surface temperature is, because that depends on many factors other than simple distance from the star and how hot the star is--just look at our own solar system, where Venus is nearly twice as far from the Sun as Mercury but has a surface temperature 100 degrees hotter due to its immensely thick atmosphere.

[Grey_Wolf_c]

Something I was curious about. How precise are we when it comes to determining the viability of other worlds? By which i mean, its easy to determine the orbit of a planet is near earth in style, but can we determine the atmosphere around it? How about the likely average temp? After all, not every sun is the same so just because its orbiting at the same distance as we are doesnt mean the star its around is putting off the same energy. Its just, the idea struck me of basically creating generational ships meant to float off into the void in the general direction of planets we think could support life, with massive seed banks to try and plant whatever crops might survive on that world, and the materials needed to create a colony on hand but then I realized I didnt know how good we were at any of the aforementioned things so for all I know that "earth-like" planet is a ball of dead rock with no water, no air, and while it was CLOSE to earth in orbit, that still creates an average temp 50 degrees higher/lower than we have at best. And we wouldnt be able to tell all that till we basically reached the world in question.


We have a fairly good grasp on star temperature, because it is closely related to their light colour, and that is easy enough to observe. From there, it is just a matter of the square-cube law to calculate the temperature areas around the star - that is what gives us the Goldilocks areas where water is liquid.

If the planet is between us and their star - for known exoplanets that is usually the case, since that is the most basic form of exoplanet detection - then we can perform spectral analysis on the atmosphere, and get a decent idea of what the atmosphere is composed of.

We can also get a bit of an idea of the gravity based on how much it makes it parent star wobble, although as you can imagine, that tends to only work with truly massive planets that will have non-human-friendly gravity. For rocky planets that are more Earth-like, astronomers tend to make reasonable guesses based on the density of our own rocky planets and the observed size of the exoplanet.

Grey Wolf

[halfeye]

Something I was curious about. How precise are we when it comes to determining the viability of other worlds? By which i mean, its easy to determine the orbit of a planet is near earth in style, but can we determine the atmosphere around it? How about the likely average temp? After all, not every sun is the same so just because its orbiting at the same distance as we are doesnt mean the star its around is putting off the same energy. Its just, the idea struck me of basically creating generational ships meant to float off into the void in the general direction of planets we think could support life, with massive seed banks to try and plant whatever crops might survive on that world, and the materials needed to create a colony on hand but then I realized I didnt know how good we were at any of the aforementioned things so for all I know that "earth-like" planet is a ball of dead rock with no water, no air, and while it was CLOSE to earth in orbit, that still creates an average temp 50 degrees higher/lower than we have at best. And we wouldnt be able to tell all that till we basically reached the world in question.

What would it take to create a permanent colony on a world like that? Is it currently theoretically possible to create a sustainable atmosphere through something like say, sealed off domes? To have enough water for a permanent internal eco system of sorts? Assuming dead rock ball is about as good as it gets, but also as bad as it gets, meaning earth like gravity, the floor isnt lava, the air isnt acid, and the "seasons" are within tolerance levels.

I think I recommend avoiding planets.

If there are asteroids in the system you can build new ships.

[Kato]

I think GW gave a good answer to the question 'how much do we know'. We're pretty good at finding out a lot but there will be some things we cannot be sure about. e.g. If an oxygen rich atmosphere means there's some kind of life or if it's something else. And size and mass of smaller planets is iirc harder than big gassy ones.


As for the structure building.. I'm gonna be a bit optimistic there. We can build huge airtight things. We might want to double and triple proof them but we're great at that too.
The problem is getting the stuff there or how to build it with no infrastructure in place. You can slowly build up from a measly ten people starting point but that will take some time..