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Gif: NASA/JPL-Caltech

A comet discovered at the end of August is just the second interstellar object spotted on a path through our solar system, but scientists think it may be a harbinger of more to come.

What's happening: According to a new study accepted for publication by The Astrophysical Journal Letters, astronomers should expect that at least a few, large interstellar objects will fly through our solar system each year.

Why it matters: These objects, which include this year's 2I/Borisov — formerly called C/2019 Q4 (Borisov) — and 2017's 'Oumuamua, represent the best chance scientists have to study material from distant solar systems at close range.

  • By learning more about comets and asteroids from elsewhere in the galaxy, researchers might be able to figure out just how unique our solar system is.

Details: The new study suggests that interstellar objects may be flung out of their solar systems during the planet formation process.

  • The authors of the study found that planets that form far from their star may eject a fair amount of material from their home solar systems, sending them out through interstellar space.
  • “This idea nicely explains the high density of these objects drifting in interstellar space, and it shows that we should be finding up to hundreds of these objects with upcoming surveys coming online next year,” Gregory Laughlin, an author of the study, said in a statement.
  • It's also possible there could be hundreds of smaller interstellar objects that pass through the solar system each year, according to the study.

Yes, but: This study is based on limited data, outside experts told Axios, and it will take new tools coming online in the coming years to truly characterize how many of these interstellar objects pass through the solar system annually.

  • "With LSST [Large Synoptic Survey Telescope] up and running in a few years (hopefully) we will be able to test whether this theory is right, and I look forward to that," Ye Quanzhi, an astronomer at the University of Maryland, told Axios via email.

Go deeper: NASA emails reveal agency's surprise at asteroid's near-miss of Earth

Go deeper

Coronavirus cases fall in 41 states

Expand chart
Data: The COVID Tracking Project, state health departments; Map: Andrew Witherspoon/Axios

New coronavirus infections fell by 16% over the past week — the third straight week of significant improvement.

Yes, but: The U.S. is still averaging roughly 165,000 new cases per day, meaning the virus is still spreading largely unchecked. And the rise of more contagious variants will ensure that Americans’ risk remains high.

Updated 3 hours ago - World

Biden reviews U.S. arms deals with Saudi Arabia and UAE

Trump struck several large arms deals with Mohammed bin Salman (L) and Saudi Arabia. Photo: Kevin Dietsch-Pool/Getty Images

The Biden administration has put on hold two big arms deals with Saudi Arabia and the United Arab Emirates which were approved in the final weeks of the Trump administration, a State Department official told Axios.

Why it matters: The sales of F-35 jets and attack drones to the UAE and a large supply of munitions to Saudi Arabia will be paused pending a review. That signals a major policy shift from the Trump era, and may herald sharp tensions with both Gulf countries.

Trump supporter found with pipe bombs accused of plot to attack Democrats

Five improvised explosive devices that the FBI says "were fully operational and could cause great bodily harm or injury if handled improperly." Photo: FBI/Justice Department

The FBI believes California Gov. Gavin Newsom (D) and the Bay Area headquarters of Twitter and Facebook were targets of a man facing federal explosives charges, according to a criminal complaint.

Driving the news: Prosecutors charged Ian Benjamin Rogers after finding weapons including five pipe bombs, 49 guns and thousands of rounds of ammunition following a Jan. 15 search of his Napa County home and auto repair business. His alleged goal was to ensure former President Trump remained in office.