Following the discovery of a new group of massive comets called “centaurs,” research scientists have warned that Earth could be at a higher risk of impact than previously thought. Scientists warn that an impact involving one of hundreds of the newly-discovered rogue comets called centaurs — some of which are up to 60 miles wide — could wipe out life from Earth.
The newly-discovered comets, numbering in hundreds, have increased dramatically the number of space rocks that are potentially a threat to Earth. Although NASA astronomers have focused attention on space rocks in the asteroid belt between Mars and Jupiter as major threats, and are currently tracking more than 12,000 near-Earth asteroids (NEAs), including more than 1,500 potentially hazardous asteroids (PHAs), discovery of the centaur comets in the last two decades suggest that to fully assess the risk of a catastrophic impact astronomers may have to look beyond near-Earth asteroids at hundreds of massive comets with larger orbits lurking beyond those of Jupiter and Neptune.
Agence France Press reports that Bill Napier, one of the study authors with the University of Buckingham, said that “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… 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 it’s time to understand them better.”
“An assessment of the extraterrestrial impact risk based solely on near-Earth asteroid counts, underestimates its nature and magnitude.”
Centaurs, like other comets, are chunks of ice and dust. The centaurs are massive comets, many 31-61 miles (50-100 kilometers) wide. Although researchers have no proof of an imminent danger, they warn that centaurs have unstable and elliptical orbits beyond Neptune, and that encounters are unpredictable.
Astronomers warn that a comet strike may have caused the major extinction event that brought an end to the Cretaceous age of dinosaurs 65 million years ago.
The danger to Earth arises mainly from the fact that the orbits of the comets cross those of the giant planets Jupiter, Saturn, Uranus, and Neptune. Interaction of the comets with the gravity fields of the giant planets could cause deflection of one or several into the inner solar system.
When a large comet approaches the Sun, it breaks up into several smaller pieces that constitute the familiar comet debris tail. The comet thus subjects the inner solar system to a deadly shower of debris.
According to the team of researchers in a study published in the Royal Astronomical Society journal, Astronomy and Geophysics, “The disintegration of such giant comets would produce intermittent but prolonged periods of bombardment lasting up to 100,000 years.”
“A centaur arrival carries the risk of injecting into the atmosphere… a mass of dust and smoke comparable to that assumed in the nuclear winter studies,” the study said. “In terms of magnitude, its ranking among natural existential risks appears to be high.”
“A centaur arrival carries the risk of injecting, into the atmosphere… a mass of dust and smoke comparable to that assumed in the nuclear winter studies.”
With the inner solar system exposed to comet debris bombardment lasting up to 100,000 years, an impact with our planet becomes practically inevitable, according to scientists who estimate that such an event may occur once every 40,000-100,000 years and that a previous deadly bombardment may have caused the extinction of dinosaurs 65 million years ago.
Scientists warn that another event could spell disaster for our planet and human civilization.
Despite believing that comets may pose a danger to life on Earth and that they may have caused extinction of the dinosaurs, scientists also believe that comet bombardments in the past may have introduced water and organic molecules from which life emerged.
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