Ancient Earth was blasted by barrage of asteroids up to 25 miles wide, page 1

Ancient Earth was blasted by barrage of asteroids up to 25 miles wide

• Findings from analysis of tiny 'spherules' in present-day rocks
• Rocks from asteroid belt between Mars and Jupiter four billion years ago
• Bombardment lasted up to two times as long as previously thought

Between three and four billion years ago, changes in an asteroid belt between Mars and Jupiter hurled a devastating barrage of space rocks at our planet.

Some of the asteroids were bigger than the 9-mile rock that wiped out the dinosaurs - but the 700-million-year barrage may have delivered chemicals crucial to the beginnings of life on our planet.

Some of these impacts were several times larger than the Chicxulub impact that killed off the dinosaurs 65 million years ago,’ Johnson said. ‘The impacts may have played a large role in the history of life. The large number of impacts may have helped simple life by introducing organics and other important materials at a time when life on Earth was just taking hold.’

A 40-kilometer asteroid would have wiped out everything on the Earth's surface, whereas the one that struck 65 million years ago killed only land animals weighing more than around 20 kilograms.

The period of heavy asteroid bombardment - from 4.2 to 3.5 billion years ago - is thought to have been influenced by changes in the early solar system that altered the trajectory of objects in an asteroid belt located between Mars and Jupiter, sending them on a collision course with Earth.

Daily Mail

Its interesting to speculate whether those chemicals crucial to the beginnings of life delivered to earth by asteroid perhaps contained life itself.

Meteor Crater in Northern Arizona: Some of the asteroids were bigger than the 9-mile rock that wiped out the dinosaurs - but the barrage continued for up to 700 million years, as an entire asteroid belt 'emptied' itself at our planet