What exactly killed the Dinosaurs? Scientists seem to have an answer

By Rahul Vaimal, Associate Editor
  • Follow author on
Dinosaurs and Comet Image
Representational Image

While the dominant theory around the abrupt extinction of Dinosaurs revolves around an earth-shattering impact created by the collision of an external body with the earth around 66 million years ago, there has been very little clarity on the object which hit the planet or its origin to date.

A recent paper published by researchers at Harvard University is proposing a new theory that suggests that long-period comets originating from the Oort cloud, an icy sphere of debris at the edge of the solar system, could be behind the incident.

Speaking about the newly published paper, Prof. Avi Loeb from the university stated that “our paper provides a basis for explaining the occurrence of this event.”

The study published in the Scientific Reports theorizes that the Chicxulub impactor, the body which collided with earth to create 93 miles wide and 12 miles deep crater off the coast of Mexico, could have been influenced by Jupiter.

Researchers used statistical analysis and gravitational simulations to calculate that a considerable portion of long-period comets originating from the Oort cloud could be pushed off by Jupiter’s gravitational field during orbit.

“The solar system acts as a kind of pinball machine,” Dr. Amir Siraj from Harvard University elaborated while trying to explain the theory adding that “Jupiter, the most massive planet, kicks incoming long-period comets into orbits that bring them very close to the Sun.”

Sun Grazers

Dr. Siraj attributed stargrazing, a phenomenon where comets, when passing close to the Sun often break apart into pieces creating cometary shrapnels hurling into space. “On the journey back to the Oort cloud, there’s an enhanced probability that one of these fragments hit the Earth,” the Harvard University scholar added.

The new calculations made as per Dr. Siraj and Loeb’s theory raise the probability of long-period comets impacting Earth by a factor of about 10 while showing that close to 20 percent of long-period comets become sungrazers.

Evidence found at the Chicxulub crater also supports the duo’s theory as the crater in Mexico contained rock compositions of carbonaceous chondrite, a compound that is widespread amongst long-period comets.