I first encountered the three-body problem 60 years ago, in a short story called “Placet is a Crazy Place” by American science fiction writer Frederic Brown. In Brown’s story, Placet is a planet in a ...

Nearly 70 years after the launch of Sputnik, there are so many machines flying through space, astronomers worry their light pollution will soon make it impossible to study other galaxies with ...

Earth’s orbit is filling up with junk. Greenhouse gases are making the problem worse. At any given moment, more than 10,000 satellites are whizzing around the planet at roughly 17,000 miles per hour.