New interstellar object 3I/ATLAS: Everything we know about the rare cosmic visitor

Hey, Space Placers!

ESA observations of 3I/ATLAS on July 2. (Image credit: ESA)

FROM UPDATE ARTICLE:

Named 3I/ATLAS, where 3I stands for "third interstellar", and designated C/2025 N1 (ATLAS), the object was first spotted on July 1, 2025, by the Deep Random Survey remote telescope in Chile, part of the ATLAS (Asteroid Terrestrial-impact Last Alert System) project.

Initially referred to by the temporary designation A11pl3Z, 3I/ATLAS drew immediate attention from astronomers because of its peculiar motion. Rapid follow-up observations and reanalysis of previous data led to the preliminary conclusion that the object was not bound by the sun's gravity. That makes it an interstellar object — only the third ever seen after 1I'Oumuamua in 2017 and 2I/Borisov in 2019. "If confirmed, it will be the third known interstellar object from outside our solar system that we have discovered, providing more evidence that such interstellar wanderers are relatively common in our galaxy," Mark Norris, Senior Lecturer in Astronomy at the University of Central Lancashire, told Space.com at the time of 3I/ATLAS’s discovery.

Even more exciting? 3I/ATLAS is the largest and brightest interstellar object yet, which means it could help scientists unlock clues about the formation of other star systems.

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With all of the new instrumental capabilities we have now in space and ground we are going to learn A LOT about ANOTHER stellar system.

I can hardly wait until 3I/ATLAS is in my telescope!

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Sky Guy in VA