The closest solar system to ours is located about 4.3 light-years away from Earth. It’s known as Alpha Centauri, and it’s the place where at least three planets revolve around the Proxima Centauri host star.
In other words, finding interstellar objects is a pretty difficult task. By definition, these cosmic bodies need to not be gravitationally bound to any star. But new research suggests that interstellar objects might exist in our own “backyard” – on the Moon itself, meaning “only” 384,400 kilometers away from Earth. Or at least astronomers might find the aftermath of collisions with such cosmic bodies there.
At least one ISO has collided with the Moon
According to the new research, interstellar objects (ISOs) might have collided with our Moon throughout its history. If we take a look at our natural satellite’s numerous craters, which are visible even by using a binocular or a home telescope, the idea doesn’t sound too crazy anymore. With or without interstellar objects crashing there, what’s for sure is that the Moon didn’t have a quite peaceful past.
By “interstellar objects,” astronomers can mean either comets or asteroids.
Sam Cabot, the lead author of the study and a Ph.D. candidate at Yale University, explained for Space.com:
Given the number of ISOs that we expect to encounter in the solar system, there are probably a few craters that were formed by very high-speed ISOs throughout the solar system, and there are probably one or two on the moon.
Finding traces of interstellar objects on the Moon is surely not an easy task, so astronomers have a lot of work to do. ISOs are still pretty rare, considering that the world has only discovered two of them so far: Borisov and ‘Oumuamua.
“Ground truth” rather than remote observations will be needed for astronomers to determine if our Moon indeed features any aftermath of collisions with interstellar objects.