Washington: A new study suggests that Planet X, a suspected ninth planet in our solar system, may have caused periodic mass extinctions on Earth, including the disappearance of the dinosaurs.
Researchers believe that the yet undiscovered 'Planet X' triggers comet showers linked to mass extinctions on our planet at intervals of approximately 27 million years.
According to Daniel Whitmire, from University of Arkansas in US, and his colleagues, as Planet X orbits the Sun, its tilted orbit slowly rotates and the planet passes through the Kuiper belt of comets every 27 million years, knocking comets into the inner solar system.
Pointing to the fossil record, which shows some evidence that comet showers on Earth happen about every 26-27 million years. Whitmire added: "In 1985, a look at the palaeontological record supported the idea of regular comet showers dating back 250 million years," the University of Arkansas explains. "Newer research shows evidence of such events dating as far back as 500 million years."
The researchers believe that Planet X would be between one and five times the mass of Earth, and about 100 times more distant from the Sun.
"What's really exciting is the possibility that a distant planet may have had a significant influence on the evolution of life on Earth," said Whitmire.
Even as evidence for a ninth planet in our solr system grows, scientists have been looking for Planet X in the solar system for 100 years.
The study was published in the journal Monthly Notices of the Royal Astronomical Society.
(With PTI inputs)