Skip to main content
Space Exploration

Return to Answer

added 196 characters in body
Source Link
N. Virgo
N. Virgo
  • 328
  • 1
  • 9

You probably also need nitrogen in the atmosphere, unless there is already nitrogen in the soil. But nitrogen is also very common in planetary atmospheres, so it's likely that it will be there.

Alternatively, if the atmosphere isn't suitable for plants or cyanobacteria, you might try building domed habitats instead, but I'll skip over that possibility, because I think you're more interested in having plants grow outdoors.

Alternatively, if the atmosphere isn't suitable for plants or cyanobacteria, you might try building domed habitats instead, but I'll skip over that possibility, because I think you're more interested in having plants grow outdoors.

You probably also need nitrogen in the atmosphere, unless there is already nitrogen in the soil. But nitrogen is also very common in planetary atmospheres, so it's likely that it will be there.

Alternatively, if the atmosphere isn't suitable for plants or cyanobacteria, you might try building domed habitats instead, but I'll skip over that possibility, because I think you're more interested in having plants grow outdoors.

Source Link
N. Virgo
N. Virgo
  • 328
  • 1
  • 9

There are a lot of specific factors that would be relevant for answering this. Here are a few:

  • What is the composition of the planet's atmosphere?

  • Is there any soil/regolith and what is it made of?

  • Does the planet have plate tectonics? (This is indirectly relevant for answering some of the above questions.)

  • Is there liquid water on the planet? Is there a water cycle? (i.e. does it rain?)

  • Is there native life on the planet already?

Most likely we would know the answers to all of these questions long before we were able to send any space ships there, so I'll assume we do know them. (Sending spacecraft to exoplanets gets into serious science fiction technology, but understanding their composition through remote sensing is something we've already started to do, and we will get a lot better at it in the coming decades.)

The atmospheric composition is important because plants need both oxygen and CO2 in order to grow. If you don't have CO2 then growing anything on the planet will be hopeless, because all living things need carbon. But luckily CO2 is very common in planetary atmospheres, so it's likely there will be some.

Oxygen is a bit trickier. In our Solar system, only the Earth has a substantial amount of oxygen in its atmosphere, and that oxygen was produced by life. So it's much less likely that your planet would have oxygen in its atmosphere, unless it had its own life already. (It's not completely impossible though, because an oygen-rich atmosphere could occur as a result of hydrogen escape.) If there is CO2 but no oxygen then you can't grow plants, but it could still be possible for cyanobacteria to grow, which are bacteria that can photosynthesise. Earth's oxygen was originally produced by cyanobacteria, before plants evolved. So if you had enough patience you could use cyanobacteria to increase the amount of oxygen, and then grow plants after that. It might take millions of years, though.

Alternatively, if the atmosphere isn't suitable for plants or cyanobacteria, you might try building domed habitats instead, but I'll skip over that possibility, because I think you're more interested in having plants grow outdoors.

Then there is the question of what the soil is made of. Mars has CO2 in its atmosphere, so maybe cyanobacteria could grow there if it wasn't so cold. But the soil there is highly oxidising, which means it's basically bleach - you would probably have to process it somehow before you'd have much chance of growing anything in it.

You mentioned that the soil on your planet is nutrient-poor, which might suggest that the planet doesn't have plate tectonics. On our planet, nutrients tend to wash into the sea and get buried in sediment, but over very long time scales they get recycled as plate tectonics moves land masses around. If that didn't happen they would just stay there, at the bottom of the sea. In that case you would either have to bring nutrients with you or engage in some serious engineering to dig them up out of the deep ocean sediments.

Then there is the question of water. If the planet doesn't have liquid water then you don't have much chance of growing anything at any scale, so let's assume it does. If it doesn't have an active water cycle then things will be a bit tricky, but it probably will have one if sunlight is able to reach the surface.

Finally there is the question of whether there is life there already. Nobody knows how life got started on Earth (though there are plenty of plausible theories), so we don't know how likely it is that life would arise if the conditions are right. But my best guess is that if conditions are already perfect for life - there is good soil, and water, and light and nutrients and so on - then it's a good bet that life will already have arisen to fill the niche. In that case, it could be that anything you grow will be eaten or out-competed by the native life, or it could be that something you introduce would be an invasive species, taking over from native species and destroying the local ecosystems. The chemistry of alien life might be very different from that of Earth life, so the effects of this might be much more severe than the effect of invasive species on Earth, and those can be pretty bad already. So if there is life there already we might decide it's better to leave it alone and study it, instead of introducing our own species. (Or at least, I hope we would decide that.)