... known they've existed since 1801, when Ceres was discovered, yet we only have a ... For the record: Ceres masses about 8.7 x 10^20 kilograms Pallas is 3.18 x 10^20 ...
... We'd have discovered them ages ago; Ceres, the largest asteroid in the main belt, is ... Let's say our killer asteroid is the same size as Ceres (remember, 900 km across). ... At that distance it is 30 times closer than Ceres. ...