Dactyl
satellite of the asteroid Ida
Quick Summary
asteroid Ida and its satellite, Dactyl
Asteroid Ida and its satellite, Dactyl, photographed by the Galileo spacecraft on August 28, 1993, from a distance of about 10,870 km (6,750 miles). Ida is about 56 km (35 miles) long and shows the irregular shape and impact craters characteristic of many asteroids. The Galileo image revealed that Ida is accompanied by a tiny companion about 1.5 km (1 mile) wide, the first proof that some asteroids have natural satellites.
Dactyl is the first confirmed natural satellite of an asteroid. It orbits the asteroid Ida, which is an S-class asteroid. Dactyl was discovered in 1993 by the Galileo spacecraft during a flyby of Ida. The moon was named after the Dactyli, mythological beings associated with Mount Ida. Dactyl is a small, irregular body, measuring approximately 1.4 by 0.8 by 0.7 km (0.87 by 0.5 by 0.43 miles). Its discovery provided the first concrete evidence for the existence of asteroid moons, a concept previously only theorized.1
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