Planet Nine, otherwise known as Planet X, is a theorized planet which may be lurking on the edge of our solar system.
In 1985, Daniel Whitmire, a maths instructor from the University of Arkansas, published a paper arguing the existence of Planet Nine.
More recently, Whitmire has said Planet Nine could be responsible for comets hitting Earth.
Put simply, the mathematician believes the mysterious planet orbits the sun like every other in our solar system, but every 26-27 million years it passes through an asteroid belt known as the Kuiper belt.
When it travels through this region, it causes comets and asteroids to deflect off it and fire out into the universe or towards our sun.
If it travels towards our host star, Earth inevitably gets caught in the crossfire, causing large space rocks to come raining down on our planet.
Whitmire argues this may have occurred 64 million years ago, resulting in the extinction of the dinosaurs and claims to have evidence to back this theory up.
An article published on the University of Arkansas’ website reads: “In 1985, a look at the paleontological record supported the idea of regular comet showers dating back 250 million years.
”Newer research shows evidence of such events dating as far back as 500 million years.”
However, Mike Brown of the California Institute of Technology (Caltech) who is the latest astronomer leading the hunt for the elusive Planet Nine, says that Whitmire is off the mark.
He told Discovery News: “Whitmire has been speculating for decades about a very distant very massive planet pushing comets around.