Astronomers are rolling out a welcome mat for a newly identified visitor from beyond our solar system.
The object — thought to be a comet — is only the third-ever confirmed interstellar visitor to pass through our cosmic neighborhood.
Dubbed 3I/ATLAS, the comet poses no danger to Earth and will remain roughly 150 million miles away as it speeds by, according to NASA.
The interstellar comet was first spotted on Tuesday by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Rio Hurtado, Chile. The NASA-funded survey telescope — which is actually made up of two telescopes in Hawaii, one in Chile and a fourth in South Africa — is designed to scan the entire sky several times each night, searching for asteroids that could pose a threat to Earth.
Researchers combed through archival data from three different ATLAS telescopes and the Zwicky Transient Facility at the Palomar Observatory in California, and found corresponding observations that helped confirm the discovery. Other telescopes around the world also joined the effort, according to NASA.
“ESA’s Planetary Defenders are observing the object, provisionally known as #A11pl3Z, right now using telescopes around the world,” the European Space Agency said Wednesday in a post on X.
The comet is currently about 420 million miles away, moving quickly from the direction of the constellation Sagittarius, NASA said in a blog post about the discovery. Sagittarius is a prominent constellation in the Southern Hemisphere that points toward the center of the Milky Way galaxy.
The agency said 3I/ATLAS will swing closest to the sun around Oct. 30, passing at a distance of approximately 130 million miles, or just inside the orbit of Mars.
NASA said the comet should be visible to ground-based observatories through September, allowing time for scientists to glean additional details about the cosmic interloper, including its size. After September, 3I/ATLAS will be too close to the sun to observe with telescopes, but the object is expected to be visible again in early December, when it emerges on the other side of the sun.
The months ahead offer a rare opportunity to study a celestial tourist from beyond our solar system. The first confirmed interstellar object seen passing through the solar system was discovered in 2017 by the University of Hawaii’s Pan-STARRS1 telescope. The rocky object, named Oumuamua (Hawaiian for “a messenger from afar arriving first”), has a reddish hue and is elongated like a cigar, according to NASA.
The only other known interstellar object to pay a visit is 21/Borisov, a comet that was discovered in 2019 by an amateur astronomer named Gennady Borisov.
