A rare visitor from another star system has been spotted. It's the interstellar comet 3I/ATLAS, and it was detected on July 1 by the NASA-funded Asteroid Terrestrial-impact Last Alert System, or ATLAS.
This system is a network of four telescopes – two in Hawaii, one in Chile and one in South Africa – that continually scan the whole sky many times a night looking for moving objects. The telescope in Chile caught this comet.
Most known comets orbit the sun and are bound by the gravity of our solar system. But this object came from far beyond the pull of our Sun, traveling 137,000 miles per hour from another star.
There is no danger that this comet will get close to Earth. It will stay roughly 150 million miles away. That's about 1.5 times the distance from Earth to the sun.
This is only the third confirmed interstellar object soaring through the solar system.
The first one was sighted in 2017 and was named 'Oumuamua, which means "a messenger from afar arriving first" in Hawaiian. It was big — almost a quarter mile long, and cigar shaped. At the time, there was a controversy about whether its strange movements meant it could be a spaceship. That controversy aside, because 'Oumuamua could only be studied for 2-3 weeks, there is still debate on its origin today.
Planetary astronomer Teddy Kareta studies comets, including previous interstellar ones. He says that when it comes to comet 3I/ATLAS, "We haven't seen this object before. We'll have a couple of months to study it for real, and then it's gone forever."
Scientists are so eager to study it because they hope that lying in the depths of 3I/ATLAS is an answer to a big question: Is our solar system unique?
Kareta says that come October, when the comet gets closer to Earth, "under dark skies ... with a big telescope and some patience, maybe you might be able to see it." Which he says would be special because, "that might be the first time anyone has actually seen the light from an interstellar object with their own eyes."
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This episode was produced by Hannah Chinn and Jason Fuller. It was edited by Christopher Intagliata. Tyler Jones checked the facts. Tiffany Vera Castro and Ted Mebane were the audio engineers.
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