A star will fly into our solar system in a million years
Researchers have known for a while that a star called Gliese 710 is heading directly for our solar system, but they’ve now pinpointed precisely when it should arrive.
The star is currently hurtling through space at around 32,000 mph and is about 64 light years away. (A light year is approximately 5,878,000,000,000 miles.)
Gliese 710 is about half the size of our sun and is expected to reach Earth in 1.35 million years, according to a paper published in the journal Astronomy & Astrophysics in November.
And upon arrival, the star could end up just 77 light-days from Earth – one light-day equaling the distance light travels in a day, or about 26 billion kilometers, the researchers calculated.
As far as we know, Gliese 710 isn’t set to collide directly with Earth, but it will pass through the Oort Cloud, a shell of trillions of icy objects at the edge of our solar system.
So while 77 light-days seems like a relatively safe distance, the fast-moving star could burst through the cloud and shoot those icy objects and comets all around our solar system. Any of them are quite likely to collide with Earth.
“Gliese 710 will trigger an observable comet shower with an average density of about ten comets per year, lasting three to 4 million years,” the authors wrote.
The team, which hails from Adam Mickiewicz University in Poland, used measurements from the European Space Agency’s Gaia space observatory.
This new observatory is building the largest and most accurate 3D space catalog ever, totaling around 1 billion astronomical objects, meaning the data is ten times more accurate than previous predictions.
There is still an error rate of around 50%, which means that Gliese 710 could actually pass just 40 light days away.
Some scientists believe a similar event of a star passing through the Oort Cloud triggered the asteroid that wiped out the dinosaurs around 65 million years ago.
However, the Gliese 710 event might make the dinosaur extinction seem relatively minor. At its closest distance, it will be the brightest and fastest observable object in the sky, and as the authors say in the paper, it will be “the most disruptive encounter in the future and the history of the solar system”.
But it’s not the only galactic body to worry about either. There are up to 14 other stars that could approach within 3 light years of us at any time over the next million years.