Answer:
Ida is an asteroid, a small, rocky body that orbits the Sun. It was discovered in 1884 by the Austrian astronomer Johann Palisa and is about 56 km (34.8 mi) long. In 1993, the Galileo spacecraft flew by Ida and discovered that it had a small moon orbiting it, named Dactyl. This was the first discovery of a moon orbiting an asteroid and provided valuable information about the physical properties of asteroids and the formation of binary asteroid systems.