It wasn’t until the year 2000 that astronomer noticed that Asteroid 90 Antitope was not a single asteroid but a duo. Instead of a single solitary space rock these are two objects that are orbiting a common centre of gravity.
The binary asteroid 90 Antiope was discovered by powerful telescopes such as the 10 meter Keck II observatory in Hawaii. This observatory helped astronomers to state that 90 Antiope is actually a double asteroid by splitting them up.
More recent observations that have been made with the European Space Observatory has revealed 90 Antiope as two egg-shaped piles of rubble orbiting one another. Each asteroid is roughly 53 miles in diameter and the distance between them is just 106 miles.
The most interesting observation happened in 2005 when astronomers were able to focus on the pair during a mutual eclipse. During this period the shadow of one asteroid was falling on another making it easier for astronomers to get more details about the pair.
Via: Universetoday
