Double Asteroid 90 Antiope . ... Explanation: This eight-frame animation is based on the first ever images of a double asteroid ! ... Now, these premier images reveal Antiope to actually consist of two 50 mile wide asteroids separated by about 100 miles. ... Binary asteroids and asteroids with moons are believed to be rare, but observations of their orbits allow a direct determination of asteroid masses and densities. ... NASA Web Site Statements, Warnings, and Disclaimers . ...