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Teaching tools > Comets > Overview: Asteroid Ida facts > Fast Facts: Asteroid Ida
| Description | Ida was the second asteroid to be observed close up by a spacecraft, when the Space Probe Galileo took pictures as it flew by on Aug 28, 1993. These pictures showed not only that Ida has a cratered surface, but also that it has a small moon called Dactyl, which is about 1.6 x 1.2 km in diameter and orbiting 90 km away from the asteroid. |
| Age | About the same age as the Sun: 4.5 billion years |
| Location | Solar system asteroid belt |
| Avg. distance from the Sun | 429.15 million kilometers (266.66 million miles) |
| Diameter | 58 x 23 kilometers (or 36 x 14 mi) |
| Mass | 4.2 x 1016 kilograms |
| Orbital period around the Sun | 4.84 Earth years (1768 Earth days) |
| Number of moons | 1, named Dactyl |
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Ida's moon, Dactyl, is probably made from pieces
that broke off Ida during an impact.
(Image courtesy of NASA) |
Teaching tools > Comets > Overview: Asteroid Ida facts > Fast Facts: Asteroid Ida