What, or when, would aliens see, if they looked at the earth?
Answers to Space Science Questions
Answers to questions about space science, astronomy, rockets, planets, galaxies, stars...
Why does it get darker earlier in the winter than it does in the summer?
How many cells are there in the brain, and how powerful is a black hole?
Is it possible that life on Mars managed to hitch a ride on a meteorite and started life on Earth?
If a meteorite hit the earth, could life be blown onto other planets?
Are there any substances on other planets that can be used for energy?
Why don't rockets leave big holes in the ground when they launch?