Other planets are not going to have the same atmosphere as ours. Chances are we're not going to be able to breath on these planets.
Mathematical nonsense.
There are hundreds of billions of stars in this galaxy alone, with hundreds of billions of galaxies.
Each star has multiple planets.
Eventually, we will find some that support our life.
It will probably take centuries, but if our civilization will not crumble (which is quite likely actually) the exponential acceleration of technology at some point would make thinks possible which are now unthinkable, and at the same time it may make inevitable everything which now has just started to be thinkable.
There is a lot of future, and a lot of space. Most of the thinkable things will happen there.
As for us, we won't go anywhere, we're stuck on Bitcointalk