Space & Astronomy
Are comets more dangerous than asteroids ?
December 24, 2015 | 10 comments
A comet could rain destruction upon us for thousands of years. Image Credit: NASA/JPL
Our planet may be at higher risk from a large comet impact than from a conventional rocky asteroid.
Most of the objects that pose a risk to the Earth originate in the asteroid belt between Mars and Jupiter, but there is another lesser known type of object out there that could represent an even greater threat to our planet and about which we know comparatively little.
Known as 'centaurs', these giant comets are large balls of ice and dust measuring up to 60 miles across. They exist in unstable elliptical orbits around the sun and often cross paths with the gas giants Jupiter, Saturn, Uranus and Neptune.
Every now and again however one of these large comets gets deflected towards the Earth and because it breaks up as it nears the sun even a single one of these objects has the potential to bombard our planet with debris for tens of thousands of years.
"In the last three decades we have invested a lot of effort in tracking and analyzing the risk of a collision between the Earth and an asteroid," said study co-author Bill Napier.
"Our work suggests we need to look beyond our immediate neighborhood 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 itís time to understand them better."
Source: The Guardian
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