Centaurs or giant comets can be a real threat to Earth

The Earth may be more exposed to a collision with a celestial body than you think, warns a group of astronomers, who recommended in a study published on Tuesday better watch giant comets.
Most studies on potential collisions with our planet focuses on asteroids ring bodies located between Mars - outside our immediate neighbor - and the next, Jupiter, observes the quartet of researchers.
The discovery in the last two decades of hundreds of giant comets - dubbed "Centaurs" - forces you to include them in the list of potential threats, although they have much larger orbits.
These comets of between 50 and 100 kilometers in diameter have not stable elliptical orbits that depart from more distant regions Neptune, the last planet in our solar system.
Their orbits intersect the giant planets like Jupiter, Saturn, Uranus and Neptune, whose gravitational fields can occasionally deflect a comet to us once every 40000-100000 years.
Every comet disintegrates over time and his journey around the sun. In the case of centaurs, this process could produce "intermittent periods, but prolonged, bombing that would last up to 100,000 years," the scientists write in the Royal Astronomical Society Journal , Astronomy and Geophysics.
According to them, "the risk assessment based solely on the impact of asteroids near Earth underestimate the nature and magnitude of the giant comets."
In the Solar System, a centaur would disintegrate into dust and larger fragments, leaving a trail of pieces "that ocasionariam in unavoidable impacts with our planet."
"In the last three decades we have invested great efforts to determine the risk of a collision between Earth and an asteroid," says Bill Napier, the University of Buckingham, one of the authors.
"Our work suggests that we must also look beyond our immediate vicinity and seek centaurs beyond the orbit of Jupiter. If we're right, these distant comets may pose a serious threat and it's time to study them more closely," he concludes.