Could humans survive on other planets in the universe?
In my opinion : Yes .. But unfortunately we are not able to explore all the universe (limitations by actual technology).
At this moment, we didn't find another planet able to respect all the conditions for humans. This is a tricky problem.
Let's take our galaxy as example :
- First, you need to have a star similar to our sun, type G, and there are only 8% of the stars in our galaxy which this type !
N.B : if we assume that the Galaxy contains
- You have to be in the habitable zone of the galaxy (region of a galaxy in which life is most likely to develop taking several factors like major risks : supernova,...).
Let us further assume that
You need to have a planetary systems, but it seems the occurrence is quite common, so we can assume
#1/3#of these stars have planetary systems #->#0.5 billion planetary systems in the habitable zone of the galaxy remain.
The planet should be an Earth sized planet with a large satellite that stabilizes its rotational axis. If the percentage of G stars that have planetary systems and a planet of Earth size in its habitable zone is
#0.1%#, then there remain still #"500,000"#objects.
You also need some big planets in the planet system , like Jupiter for us, to attract most of the asteroids. Moreover, of the
#"500,000"#objects, we can assume only #1/1000#contain a continuous habitable zone (no nearby supernova explosion, no catastrophic impacts,...) #->#still #500#objects remain.
Then there is the factor of age . It took about
#3.5#billion years for life to develop to higher forms. How many of these #500#objects are old enough ?
If we take a crude value of
And this is with pessimistic estimation considering only G-stars, maybe we can extend with K-stars ...
Conclusion : It's not a large number but definitely different from one and only for our galaxy .. So I am pretty sure it's possible !