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Full Version: Do interstellar objects pose a threat to Earth?
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https://www.universetoday.com/articles/d...t-to-earth

EXCERPTS: We know of three interstellar objects (ISO) that have visited our inner Solar System. Oumuamua was the first one, and it came and went in 2017. 2l/Borisov, an interstellar comet, was next, appearing in 2019. And right now, the interstellar comet 3I/Atlas is enjoying a visit to the Sun-warmed inner Solar System.

A massive number of ISOs must have passed through our Solar System during its long, 4.6 billion year history. It's possible that some of them slammed into Earth. Maybe ISOs are responsible for some of the ancient impact craters whose remnants we can still see today, like the Vredefort impact structure.

Our Solar System is much more placid than it used to be. Early in its history, it was molded by chaotic collisions. There are fewer rocks and fewer collisions now because much of the rock accreted into the terrestrial planets. But the same can't be said about ISOs. There's no reason to believe there are fewer ISOs entering our Solar System than there were in the past.

That means they pose an impact risk to Earth. Is there any way to quantify that risk?

New research titled "The Distribution of Earth-Impacting Interstellar Objects" tries to understand the risk. The lead author is Darryl Seligman, an assistant professor in the Physics and Astronomy Department at Michigan State University....

[...] It bears repeating that this work doesn't predict the number of ISOs. There's no way to measure that. "In this paper we intentionally do not make any definitive predictions about the rates of interstellar impactors," the authors write in their conclusion.

But the results do feed into future observations with the Vera Rubin Observatory and its Legacy Survey of Space and Time. It gives astronomers and idea about the distribution of ISOs that should be deteced by the VRO.

We're just opening our eyes to the idea of ISOs. This paper gives us an idea of where Earth-impacting ISOs are likely to arrive from, when they're most likely to impact, and where they're most likely to impact. Once the VRO and its LSST get going, astronomers will begin to acquire data that will either support or undermine these findings... (MORE - missing details)