The moon’s craters suggest Earth hasn’t erased lots of past impacts
Existing craters hint that asteroids increasingly pummeled both some 290 million years ago
A new look at the moon’s craters suggests the Earth and moon both suffered a sharp increase in impacts around 290 million years ago, and Earth has kept its biggest scars.
Geologists long assumed that erosion and tectonic activity had erased Earth’s craters so thoroughly that “you couldn’t say anything about the craters on Earth at all,” says planetary scientist Rebecca Ghent (SN: 12/22/18, p. 40). So to figure out how much Earth was pummeled in the past, Ghent and her colleagues turned to the moon.