It is one of the most famous questions in science, and it was asked, as legend has it, over lunch. Enrico Fermi, the ...

Here's a thought experiment that keeps planetary scientists awake at night. Strip every living thing from our planet, every bacterium, every blade of grass, every creature that has ever drawn breath ...

Tardigrades are practically invincible on Earth, so scientists looked to outer space in search of their kryptonite.