This afternoon my postman delivered a review copy of The Space Book by Jim Bell. This is the latest book in a series that includes Cliff Pickover’s math, physics, and medical books. Like the other books in the series, The Space Book alternates one-page articles and full-page color images.
Here’s something I learned while skimming through the book: Asteroids can have moons. (That’s the title of the article on page 414.) This has been known since the early 1990’s, but it’s news to me.
The first example discovered was a satellite now named Dactyl orbiting the asteroid 243 Ida. The Space Book says Dactyl was discovered in 1992. Wikipedia says Dactyl was photographed by the Galileo spacecraft in 1993 and discovered by examining the photos in February of 1994. Since that time, “more than 220 minor planet moons have been found.”