The workings of our solar system are roughly the same now as they have been for millions of years. Moons circle their planets, the planets circle the sun, the sun’s magnetic fields and sunspots wax ...

And the earth was without form and void, and darkness was upon the face of the deep. Sometimes, if the night is dark and clear enough, you can look up and see the Milky Way in its arc across the sky.

There’s a bit of a paradox about our galaxy: it’s both jam-packed with stars and cavernously empty. The Milky Way is crowded in the sense that it holds hundreds of billions of stars, as well as ...