Astronomers have discovered a third moon orbiting the main-belt asteroid (130) Elektra, making it the first quadruple asteroid ever found. This image, taken by the SPHERE/IFS instrument on ESO’s Very Large Telescope in 2016, shows three satellites (S1 in red circle, S2 in green, and S3 in blue) of the main-belt asteroid (130) Elektra. Image credit: Berdeu et al., doi: 10.1051/0004-6361/202142623. First discovered on February 17, 1873 by Litchfield...
