Scientists believe a comet impact may have helped mammals take over Earth

Scientists have been conducting research into what may have helped mammals dominate the Earth. New evidence suggests that a comet impact 55 million years ago may have helped mammals become the dominant form of life on our planet. The team of American researchers on the project say that the comet impact could have triggered rapid global warming linked to the expansion of mammals in the Eocene time period.

The evidence the team of scientists point to to support their theory is spherical fragments of glass that are believed to form when molten debris thrown into the air during an impact solidifies in mid-air. Perhaps the most famous theory for what happened to the dinosaurs is that a massive asteroid strike in the Yucatan Peninsula 66 million years ago killed them all off.

Dennis Kent from Rutgers University is co-author of the new study and Kent believes that glass found in sediment cores drilled out from along the New Jersey coast could have come from a comet that measured 10 km wide slamming into the Atlantic Ocean.

He believes that this comet strike could have led to a known but mysterious release of CO2 and other greenhouse gasses that warmed the planet rapidly about 55.6 million years ago. Scientists say that the global temperatures on Earth rose by about 6C in less than 1000 years. That rapid warming period is attributed to an isotopically light form of carbon being introduced into the Earth's ecosystem. This temperature spike coincides with mammal groups spreading to new parts of the world.

A mineral discovered by Kent called lechatelierite has glassy spherules inside called microtektites and the scientist says that that mineral forms only at high temperatures around 1,700C. He believes the material was formed by high temperatures from the comet impact flinging debris into the air.