Dinosaurs were long thought to have gone extinct by a large asteroid slamming against the surface of the earth 66 million years ago. However, a new theory suggests it wasn't quite an asteroid.

NPR reports about new Harvard University research that proposed the cataclysmic fate of dinosaurs was due to a much further comet that came from the Oort cloud, an area from the edge of solar system.

Comet Slams Against Earth

The researchers, Harvard theoretical physicist Avi Loeb and undergraduate student, Amir Siraj, suggest that the comet was pulled from the Oort cloud by the gravitational force of Jupiter and then propelled close to the orbit of the sun. The tidal forces caused the comet to fragment. One fragment knocked into the coast of Mexico under what is now known as the Yucatán Peninsula.

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The researchers believe that this theory gives an answer to the origin of the Chicxulub crater, the New York Times reported.

"Our hypothesis explains the composition of the largest confirmed impact crater in Earth's history as well as the largest one within the last million years," the researchers wrote.

Research Criticism

While the theory is considered plausible, some scientists expressed criticism towards the research.

"I believe their work has several intrinsic problems," Bill Bottke, a planetary scientist at the Southwest Research Institute in Boulder, CO said, according to the New York Times.

Bottke explained that the research doesn't carefully consider how long it takes for a comet to be broken by the sun.

"I just think making that case is really hard," he added.

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