NASA discovers third interstellar comet
by Andrew Sookdeo
Washington DC (UPI) Jul 3, 2025
NASA discovered the third interstellar comet through a survey telescope in Rio Hurtado, Chile.
The interstellar comet first observed on Tuesday by NASA’s Asteroid Terrestrial-impact Alert System telescope, or ATLAS, has been officially named 3I/ATLAS.
A series of “pre-discovery” observations dating back to June 14 from three ATLAS Telescopes globally and the Zwicky Transient Facility in California’s Palomar Observatory have since been collected, along with new observations from several telescopes since the initial report.
“If confirmed, it will be the third known interstellar object from outside our solar system that we have discovered,” Dr. Mark Norris, a senior lecturer in astronomy at the University of Central Lancashire, told The Guardian.
Dr. Paul Chodas, director of the Center for Near Earth Object Studies at NASA’s Jet Propulsion Laboratory in California, told The New York Times there is “no uncertainty” that the comet is from interstellar space, noting speeds that indicate it could not have originated in our solar system.
“If you trace its orbit backward, it seems to be coming from the center of the galaxy, more or less,” Chodas said. “It definitely came from another solar system. We don’t know which one.”
The comet will reach its closest approach to the Sun around Oct. 30, but it shows no threat to Earth as it will remain at least 150 million miles away. It is currently about 416 million miles from the Sun.
In December, the comet is expected to reappear on the other side of the Sun.
The comet’s size and physical attributes are being investigated. It is expected to remain visible to ground-based telescopes through September.
Jake Foster, a Royal Observatory Greenwich astronomer, said: “At the moment, the comet is not expected to be visible to the naked eye, but it should be visible through a reasonably sized amateur telescope in late 2025 and early 2026. As it is studied more over the coming weeks, we’ll get a better idea of just how visible it will realistically be.”
In 2017 Oumunamua traveled through the solar system as the first interstellar object. In 2019, the second interstellar comet, Borisov passed by.
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