Gliese 710 is a star 64 light-years away that will reach our location in approximately 1.35 million years. Estimates show that it is likely to pass within 77 light-days of Earth’s orbit, with a margin of error that could bring it as close as 40 light-days.
The study of Gliese 710 took part primarily using the European Space Agency’s Gaia Space Observatory, which includes a 3D catalog of about one billion astronomical objects. Astronomers have spent several years using this catalog to refine their measurements of when and where this dim star will swing through our solar system’s Oort cloud and their models of what will happen to the solar system when it comes through.
Risk Of Heavy Impactors
It is expected to disrupt the orbits of icy and rocky debris in the Oort cloud, causing impressive comet showers of a frequency of about 10 comets per year and an increased risk of collision with large asteroids. Astronomers say that while objects from the Oort cloud account for only 25% of impacts, this type of impact also account for most of the larger craters on Earth.
Many scientists believe that a similar event in the distant past perturbed the orbits of Oort cloud objects that included the impactor that led to the extinction of the dinosaurs. John Matese said of it in an article for American Scientist, “Impactors that make craters greater than 100 kilometers in diameter are the ones that play [a] key role for extinction events.” This means that Gliese 710 increases the chance of another extinction event similar to the one that wiped out the dinosaurs after it passes through.
Don’t Panic – Yet
This will happen in 1.35 million years and pessimists tend to argue that something else could do us in first, such as one of the Near-Earth Objects of significant size. Just recently, the asteroid 2017 AG13 made a close approach to Earth and came within a distance of 126,461 miles of Earth, or just over half the Moon’s distance of Earth. Memorable events involving large celestial bodies entering Earth’s atmosphere within living memory include the explosion of an asteroid above Chelyabinsk, Russia, in 2013. So the supporters of good planetary defense aren’t wrong when they say that we need to be able to reliably detect and deflect possible impactors if we don’t want to become victims of the next large asteroid when Earth runs out of luck.
Even so, Gliese 710 won’t get here until the human species has (at best) evolved into a form that we might not recognize as human and (at worst) might not be around to even worry about it. When it does arrive, though, it will certainly put on a show. The investigators who studied Gliese 710 say that it will be the brightest and fastest observable object in the night sky, as well as being one of the most disruptive in the history of our solar system.