Study: Meteorite Collisions 4.4 Bil. Years Ago
Japanese researchers say intense meteorite collisions during the formation of the solar system may have occurred about 4.4 billion years ago, much earlier than previously thought.
Previous studies of Moon craters suggested a large number of meteorites collided with the Earth, the Moon, and other planets shortly after the beginning of life on Earth about 3.9 billion years ago.
Researchers are investigating how life could have survived during the period, referred to as the "late heavy bombardment."
Assistant Professor Koike Mizuho of Hiroshima University and other researchers analyzed elements of meteorites that originated from an asteroid thought to have been hit in the bombardment.
They say the results show the collisions took place 4.1 to 4.4 billion years ago, suggesting the bombardment period occurred 200 to 500 million years earlier than previously thought.
The group says analyses based solely on Moon crater samples may have been misleading.
Koike says the team believes its research will prompt a review of the early history of the Earth, around the time that life first emerged on the planet.
