Asteroids
© Newsweek.com
If you want to travel to Alpha Centauri, it'll take thousands of years using current technology. It might be easier to wait. Astronomers have long known that the triple star system is approaching Earth for a close encounter 28,000 years from now. Indeed, a new study contends that asteroids from alpha Centauri are already here.

"We estimate that a million asteroid-sized objects from the alpha Centauri system could be in the Solar System right now," says Cole Gregg, a PhD student at the University of Western Ontario (UWO) and co-author of the study just accepted by the Planetary Science Journal. This simulation from the study shows asteroids entering the Solar System as alpha Centauri passes by:


Interest in alien asteroids spiked in 2017 when 'Oumuamua raced through the solar system. Prof. Avi Loeb from Harvard argued that the cigar-shaped object might be an alien spacecraft, but most astronomers went with Occam's Razor. It was more likely a natural body from another star system, they argued.

To investigate the likelihood of such bodies, Gregg and co-author Paul Wiegert (also of UWO) decided to do a case study of Alpha Centauri, the closest star system to Earth. Within Alpha Centauri, three stars and an unknown number of planets are constantly using their gravity to scatter objects out into space. Dust, comets, asteroids, ancient planetesimals--they're all flying out of the Alpha Centauri system in a cloud like Pigpen's from the Peanut comics. Running a simulation that spanned more than 100 million years, Gregg and Wiegert showed that a significant number of these objects could reach us.

'Oumuamua
© NASAThe first known interstellar object to visit our solar system, 'Oumuamua
Alpha Centauri isn't the only star system potentially sending asteroids our way. "Quite a few have had (or will have) close encounters with the Solar System," notes Gregg. "An example of a past approach is Scholz's star, which likely passed through the Oort Cloud around 70,000 years ago. An example of a future approach is Gilese 710, which is estimated to pass by 1.3 million years from now also within the Oort Cloud."

So alien asteroids are *not* unusual. Can we now go out and find some?

It's harder than it sounds. The Solar System is a big place and even with a million Alpha Centauroids "the observable fraction of such objects remains low as there is only a probability of 10-6 that one of them is within 10 AU of the sun," write Gregg and Wiegert. A better bet is to look for meteors. Their analysis suggests that the Solar System may be littered with dust from Alpha Centauri. In the night skies of Earth, as many as 10 meteors per year may come from that distant star system.

It's something to think about the next time you see a shooting star...

Read the original research here: https://arxiv.org/abs/2502.03224