How distant asteroid collision shaped life on Earth before dinosaurs were wiped out
- Enormous dust cloud that swept solar system sent Earth into a mini ice age
- It sparked an explosion in primitive life after blocking some of the sunlight falling on Earth
The cataclysmic asteroid impact off Mexico’s coast that doomed the dinosaurs 66 million years ago was not the only time an astronomical event shaped the history of life on Earth.
Scientists on Wednesday said dust spawned by a gigantic collision in the asteroid belt between Mars and Jupiter 400 million years earlier triggered an ice age on Earth that ushered in a significant increase in marine biodiversity.
The event, occurring when life was concentrated in the seas and far before vertebrates first walked on land, set in motion evolutionary changes in invertebrates fundamental to marine ecosystems as they adapted to global cooling, they said.
The inner solar system was filled with enormous amounts of dust after an asteroid more than 150km in diameter was struck by a smaller object perhaps 20km wide, the researchers said.
It was the solar system’s largest-known break-up event in the past 2 billion years.
Solar radiation reaching Earth’s surface was reduced for at least 2 million years by the dust in space and in the planet’s atmosphere, said study co-author Philipp Heck, an associate curator at the Field Museum in Chicago.
