Curtin University Associate Professor Alexander Nemchin made the discovery when he dated a section of rock from the Moon that melted in heat of the meteorite impact.
The object that hit the Moon was probably tens of kilometers across and would have left a crater several hundred kilometers wide.
A/Prof Nemchin says the strike happened at least 300 million years before the youngest known lunar impact basins and his discovery challenges the long-held view that there was a single spike in huge impacts 3.9 billion years ago.
He says this period of intense meteorite bombardment, which would have affected both the Moon and the Earth, was previously thought to be a one-off event.
“A few years ago we started to see evidence that it’s probably not quite the case,” A/Prof Nemchin says.
“It’s possible that there are some impacts not related to this 3.9 [billion years] spike … there are some that happened much earlier.
Read more at: Phys.org