Grove Karl Gilbert was an American geologist who proposed that the Moon was formed by the accretion of small rocky particles.
The American cosmochemist Harold Urey supported this view almost sixty years later. He believed that accretion was a cold process; the Moon formed almost 4.5 billion years ago without any volcanic eruption. Rather, it took shape from cold chondritic material-small meteorite particles with mineral granules.
This was not true though. Urey was later proved wrong. Apollo observers confirmed that the maria were volcanic lava flows, and the Moon had been hot.
Urey later came up with another theory about the capture of a moon that was once formed elsewhere in the solar system. This proposition remained popular for a while.
Picture Credit : Google
