For 89 years, astronomers have played a cosmic version of Where's Waldo? Now, the game is over.
Scientists have rediscovered a near-Earth asteroid called 719 Albert, observed several times in 1911 but not seen since. Its number indicates that Albert was the 719th asteroid to have its orbit determined, a bookkeeping convention that began in 1801 with Ceres, the first asteroid identified. With Albert's rediscovery, scientists finally know the whereabouts of all 14,788 numbered asteroids.
Johann Palisa at the Imperial Observatory in Vienna spotted Albert on Oct. 3, 1911. He and other astronomers also imaged it the following night.
Astronomers soon realized that they had unwittingly photographed the rock in severa