Our solar system creates many comets that it then spits out into the inky vastness of space, presumably never to return. Only, that may not be the case forever. According to a preprint study available on arXiv and detailed by IFLScience, some of the comets our solar system has ejected might eventually circle back.
Astronomers call them “quasi-interstellar objects,” and unlike true interstellar objects, which originated from outside our solar system, such as 3I/ATLAS, whose journey through our solar system I extensively chronicled, quasi-interstellar objects would actually be our own cosmic ejections returning home after an unimaginably long trip through the galaxy.
Researchers estimate that roughly 95 percent of the comets and asteroids formed in the solar system have been flung into interstellar space over billions of years. That’s around 10,000 trillion objects all scattered into the Milky Way. Most are gone for good, but the Sun’s gravity never completely lets go. Sometimes, it might reel one of them back in.
Some Comets May Leave the Solar System, Wander the Galaxy, and Eventually Return
Their speed would help distinguish them from actual interstellar objects, as quasi-interstellar objects would be entering much more slowly, assuming we ever spot one. They’re so rare that the team estimates that fewer than one quasi-interstellar object enters the area inside Jupiter’s orbit each year, and a lot of them would likely blend in with all the other comets making the trip from the Oort Cloud, the theoretical cloud of billions of comet-like objects that surrounds our solar system.
The Oort Cloud, by the way, is considered theoretical mostly because it’s just so far away and so sparsely populated that even our most powerful telescopes have a hard time observing individual objects. But we’ve collected enough evidence over the years to strongly suggest that there’s some kind of rock cloud circling us.
Observatories around the world will probably find tons of true interstellar objects in the decades to come, but finding a boomeranging quasi-interstellar object is going to be difficult, even when we are pretty sure they were bound to show up eventually.
The post Scientists Say Some Ejected Comets Could Return to Our Solar System appeared first on VICE.
