A new study claims that dinosaurs might have been killed off by a comet, saying that the statistical possibility of a long-period comet capable of striking Earth and causing mass extinction is about one in every 3.8 billion to 11 billion years.
This basically means that dinosaurs might have been killed off by a large piece of a comet, not an asteroid, as backed up by researchers at Harvard University who believe there is evidence that a piece of comet crashed into Earth 66 million years ago to create the Chicxulub crater.
The impact created the 110-mile-wide crater which is located on the Yucatán Peninsula and is thought to be the source of the mass extinction event that eradicated dinosaurs and most of Earth’s species.
Through statistical analysis and gravitational simulations, the study determines where the impactor (asteroid or comet) came from and how it came to strike Earth.
In a scientific report, Avi Loeb and Amri Siraj suggested that a large piece of a long-period comet – a piece of space debris composed mostly of frozen gas – could have been the impactor, not an asteroid (aka, a rock).
Whilst asteroids are typically found in the Asteroid Belt between Mars and Jupiter, comets are normally found further out in the solar system, past Jupiter’s orbit.
Loeb and Siraj theorise that a comet from the Oort cloud – a group of space debris – was bumped off course by Jupiter’s gravitational field, bringing it closer to the sun. Siraj explained, ‘Jupiter kicks these incoming long-period comets into orbits that bring them very close to the sun.’
He continued, ‘You get what’s called a tidal disruption event and so these large comets that come really close to the sun break up into smaller comets. And basically, on their way out, there’s a statistical chance that these smaller comets hit the Earth.’
After a comet is broken up by the sun, it is 10 times more likely to hit Earth. They also suggest this theory could explain the impactors that created the Vredefort crater, which is the largest confirmed crater in Earth’s history.