Earth could be dotted with wayward deadly comets in just over a million years when a wandering star enters the outer reaches of the solar system.
Popular culture is replete with cosmic doomsday scenarios, many of which involve scientists detecting a large asteroid hurtling towards Earth. Comets, huge chunks of ice and earth that encompass the entire solar system in a huge sphere known as the Oort cloud, are perhaps less prominent in fictional catastrophes.
This may change in the distant future.
Currently, Earth’s closest star to the sun is called Proxima Centauri, located about 4.25 light-years away. But our galaxy is a dynamic, ever-changing place, and in about a million years, Earth will have a new, much closer stellar neighbor.
Gliese 710 is a small star currently located about 62 light-years from Earth in the constellation Serpens Cauda. Scientists have known for about two decades that Gliese 710 is heading straight for the solar system, and in about 1.29 million years it will arrive just 0.06 light-years from Earth, according to a 2018 study – l a hair’s breadth, in cosmic terms.
Luckily for Earth, and any life that might still be living there at this time, Gliese 710 itself won’t directly harm us at this distance. However, the star’s pass could still have catastrophic effects.
0.06 light-years away, Gliese 710 will pass through the Oort Cloud, disrupting countless comets. Many of them can be thrown into deep space. Many more will be rushed to the inner solar system. When that happens, asteroids might pale in comparison.
“For the same mass, comets would cause ten times more damage to Earth than an asteroid,” said Professor Brad Gibson, director of the EA Milne Center for Astrophysics at the University of Hull. Newsweek. “Early phases of planet formation saw such cometary impacts occur more regularly; there had been much debate as to whether the impact event that wiped out most species on Earth 65 million years, including the dinosaurs, was a comet or a The consensus seems to be that it was an asteroid now, but there are real concerns about the future of Earth.
“In just one million years, a sun-like star called Gliese 710 will actually enter our solar system and slowly pass through the Oort cloud of comets. The effect of this passage will be to shake over ten million comets that are predicted to rain on the inner solar system.
“We’ve got Jupiter sucking up a lot of them, much like it did in 1994 when it sucked up comet Shoemaker/Levy before it could get close to us, but the numbers are such that if something astrophysical has the potential to completely destroy our biosphere, it will be one of those millions of comets that will arrive in just one million years!”
Obviously, this eventuality is far away. For now, scientists are keeping a close eye on the skies for any asteroids or comets that might appear to pose a threat, and thousands are being continuously tracked.
“Comets have hit Earth in the past, and they will again in the future,” said Alan Fitzsimmons of the Center for Astrophysics Research at Queen’s University Belfast. Newsweek. “But because there are so many more asteroids passing close to our planet, that’s where the biggest risk still lies. The good news is that our survey telescopes are designed to discover both asteroids and comets that might be heading our way. We now have a good chance of seeing anything on a possible impact trajectory and issuing a warning.”
The potential threat of a hail of comets in just over a million years shows how important such vigilance can be.