As 2015 ends, it is inevitable that another end-of-the-world scenario looms. A new study, published in the Astronomy and Geophysics journal, warns of giant comets with unstable, elliptical orbits that begin beyond Neptune and could possibly hit and destroy Earth.

These giant comets, also called centaurs, were only discovered by astronomers in the last 20 years, reports Discovery. Prior to its discovery, studies of potential space object that could collide with the planet concentrated on the asteroid belt that lies between Mar and Earth on one side, and Jupiter and Earth on the other side.

Since effort has been focused on monitoring and analysing the risk of an asteroid and Earth collision in the last 30 years, the research points to the need to “look beyond our immediate neighbourhood too, and look out beyond the orbit of Jupiter to find centaurs,” says Bill Napier, co-author of the study and from the University of Buckingham.

These giant comets cross the paths of four large planets – Jupiter, Saturn, Uranus and Neptune – which have gravity fields that could deflect a comet toward Earth. However, while that galactic event is rare, estimated by scientists at once every 40,000 to 100,000 years, the centaurs, nevertheless, are serious hazards to Earth.

The scientists believe it was a comet strike on Earth that was responsible for the destruction of the dinosaur population on the planet 65 million years ago. If the centaurs draw closer to the Sun because of their deflection, it could break up and create comet tails that risks colliding with Earth.

The researchers warn, “The disintegration of such giant comets would produce intermittent but prolonged period of bombardment lasting up to 100,000 years.” This new threat exposes the underestimation by astronomers of the nature and magnitude of possible extraterrestrial impact risks since it only identified near-Earth asteroids as the only threats.”

A centaur brings with it a mass of dust and smoke similar to conditions forecast in a nuclear event, particularly the release of soot by firestorms during an atomic war. Sciencerecorder points out that if the study is correct, more research should be conducted to observe how comets operate and fly while deeper in space.

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