In the Solar System
Ida
A main-belt asteroid, here because Galileo flew past it in August 1993 on the way to Jupiter - and found the first moon ever seen round an asteroid, a kilometre-wide rock now called Dactyl. Until that picture it was an open question whether such a thing could exist; the moon's orbit also gave the first direct measurement of an asteroid's mass.
- Radius
- 16 km
Everything the map shows is worked out in your browser from published orbital data - nothing on it is a stored picture of where things were.