42 of the largest asteroids: from spheres to dog bones

More than 650,000 objects orbit in the solar system’s asteroid belt between Mars and Jupiter. Astronomers at the European Southern Observatory ESO imaged 42 of the largest in a large-scale effort from 2017 to 2019; the results have now been published. What did they notice?

Different shapes: By reconstructing the shapes of the objects, the team found that the observed asteroids are divided into two families. Some are almost perfectly spherical, such as Hygiea and Ceres, while others have an elon...