Abstract
The inner solar system's biggest and most recent known collision was the Moon-forming giant impact between a large protoplanet and proto-Earth. Not only did it create a disk near Earth that formed the Moon, it also ejected several percent of an Earth mass out of the Earth-Moon system. Here, we argue that numerous kilometer-sized ejecta fragments from that event struck main-belt asteroids at velocities exceeding 10 kilometers per second, enough to heat and degas target rock. Such impacts produce ∼1000 times more highly heated material by volume than do typical main belt collisions at ∼5 kilometers per second. By modeling their temporal evolution, and fitting the results to ancient impact heating signatures in stony meteorites, we infer that the Moon formed ∼4.47 billion years ago, which is in agreement with previous estimates.
Original language | English (US) |
---|---|
Pages (from-to) | 321-323 |
Number of pages | 3 |
Journal | Science |
Volume | 348 |
Issue number | 6232 |
DOIs | |
State | Published - Apr 17 2015 |
ASJC Scopus subject areas
- General