A new research paper has suggested that the hundreds of giant mass extinction-causing comets that have been discovered in our outer solar system pose a far greater risk to the human race than first thought.
The paper, published in the December issue of Astronomy & Geophysics, proposes that these huge 100-mile wide ice giants could have been responsible for the numerous extinction events that have taken place during the Earth's relatively short lifespan.
Known as 'Centaurs' these giant comets follow no stable orbital pattern making them incredibly hard to predict.
If that wasn't enough they're often found near to the enormous outer planets Jupiter, Saturn and Neptune with their corresponding gravitational fields more than capable of catapulting these enormous objects towards Earth.
Then of course there's the size. The researchers at the University of Buckingham found that just one of these Centaurs could contain more mass than the combined mass of every asteroid discovered in our solar system to date. Gulp.
Centaurs wouldn't ever hit the Earth as one giant ball, instead these massive balls of ice would break up into smaller particles ranging in size from a pea to a solid lump the size of London.
Lead researcher Professor Bill Napier said:
"In the last three decades we have invested a lot of effort in tracking and analysing the risk of a collision between the Earth and an asteroid."
"Our work suggests we need to look beyond our immediate neighbourhood too, and look out beyond the orbit of Jupiter to find centaurs. If we are right, then these distant comets could be a serious hazard, and it’s time to understand them better."
There is some good news though, centaurs have historically only every crossed our path every 40,000-100,000 years and with the next one not due for some time it's likely that by the time it does, we'll be ready to deal with it.