The Asteroid With Its Own Moon

Logic would dictate that anything smaller than a planet doesn’t have the gravitational pull to hold onto a moon, but thats not always the case. Enter243 Ida, an asteroid that’s only 30 kilometers (19 mi) across when you measure it the longest possible way. Ida has a tiny, 1.6-kilometer (1 mi) moon orbiting it (Dactyl). It’s the first binary system of asteroids that we found and the only one we’ve done a close enough flyby of to get clear pictures, but we’ve since discovered over a dozen binary asteroids.