Ceres is covered in countless small, young craters, but none are larger than 175 miles (280 km) in diameter. This is a huge mystery, given that the dwarf planet must have been hit by numerous large asteroids during its 4.5 billion-year lifetime. Where did all the large craters go? A new study explores this puzzle using data from NASA Dawn Mission. "We concluded that a significant population of large craters on Ceres has been obliterated beyond recognition over geological time scales, which is li