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For only the 3rd time in history, astronomers have found an interstellar object hurtling through our solar system. The newly discovered space rock, now named 3I/ATLAS, could be as large as 12 miles (20 km) in diameter. And it’s soaring toward the sun at a blistering pace.
UPDATE: The newly discovered space rock has a new designation, 3I/ATLAS. And that letter I stands for interstellar. So we have a visitor from another solar system! The Minor Planet Center (MPC) confirmed its new designation on July 2, 2025, as 3I/ATLAS, or C/2025 N1. The MPC also said:
There are tentative reports of cometary activity … with a marginal coma and a short 3-arcsecond tail.
So it’s official! We are currently being visited by what appears to be a comet from another solar system.
New interstellar object visiting our solar system
There’s a new object in the solar system headed toward the sun, and it appears it came from interstellar space. We only know of two other interstellar objects that have entered into our solar system before, ‘Oumuamua and Comet 2I/Borisov. The nature of ‘Oumuamua is still a matter of debate, and the second was a comet from another solar system. And now we have a third interstellar visitor. First named A11pl3Z, the object is now designated as 3I/ATLAS, or C/2025 N1. The object’s trajectory indicates it didn’t originate inside our own solar system.
The International Astronomical Union’s Minor Planet Center first added the object to their Near-Earth Object confirmation list on July 1, 2025. The object is also on NASA/JPL’s website for Near-Earth Object Confirmation Page under A11pl3Z. Despite being listed as a near-Earth object, there is no fear of it hitting Earth or even coming particularly close.
So what is the new visitor? Well, it’s likely either a comet or an asteroid. Current indications are leaning toward it being a comet.
View at EarthSky Community Photos. | Filipp Romanov captured the new candidate for interstellar object, A11pl3Z, on July 2, 2025. Filipp wrote: “I confirmed new interstellar object candidate A11pl3Z remotely using iTelescope.Net T72 (0.51-m f/6.8 reflector + CCD) in Chile.” Thank you, Filipp!Observations of the visitor
Astrafoxen, an astrophysics undergrad student in California on Bluesky, has shared an image of A11pl3Z from the Deep Random Survey in Chile. Additionally, Sam Deen, a prolific amateur astronomer, found earlier images of the object in ATLAS data from June 25 to 29. These data points help show the track of the object, indicating that it is almost certainly interstellar.
The dim space rock is currently at about magnitude 18.8. Our new visitor will get its closest to the sun – at about 2 astronomical units (AU), or twice as far as Earth is from the sun – in October. As it reaches perihelion – its closest point to the sun – it should be moving at about 68 km/s relative to the sun, or at about 152,000 miles per hour.
Marshall Eubanks, a physicist and VLBI radio astronomer and co-founder of Space Initiatives, said on the Minor Planet Mailing List that the object could be as large as 12 miles (20 km) in diameter. It will also come within about 0.4 AU of Mars in October, which would make it just barely observable by the Mars Reconnaissance Orbiter. With the current orbital data, Eubanks said:
This object appears to be coming from the thin galactic disk.
Eubanks also said:
Note that next April (2026) it will have a velocity relative to Earth of about 90 km/s. That should set a record.
Locator maps for our interstellar visitor
Eddie Irizarry shared maps of the location of 3I/ATLAS. Eddie said in an email to EarthSky:
Although Comet 3I/Atlas is currently dim at a magnitude around 17.5, advanced amateur observers might be able to photograph the new visitor by taking long exposure images through a telescope, as some equipment can reach such magnitudes.
By August, the new comet should reach magnitude 16 and gradually improve, allowing more astrophotographers to capture this rare object.
Here’s the location of new interstellar object, 3I/Atlas, on July 2, 2025, at 10:45 pm CT / 11:45 pm ET. It will be above the Teapot of Sagittarius. Image via Eddie Irizarry/ Stellarium.
Here’s a closeup look at where the interstellar visitor will be on the evening of July 2, 2025. Image via Eddie Irizarry/ Stellarium.
Here’s where the new interstellar visitor will be on July 3, 2025, at 10:45 pm CT / 11:45 pm ET. It appears near the star cluster M3. Image via Eddie Irizarry/ Stellarium.
Location of the new visitor on July 5, 2025, at 10:45 pm CT / 11:45 pm ET. Image via Eddie Irizarry/ Stellarium.
Location of Comet 3I/Atlas on July 15, 2025, at 10:45 pm CT / 11:45 pm ET. Image via Eddie Irizarry/ Stellarium.
Location of the new visitor on July 20, 2025, at 10:45 pm CT / 11:45 pm ET. Image via Eddie Irizarry/ Stellarium.Chatter on Bluesky
Astronomers may have just discovered the third interstellar object passing through the Solar System!
ESA’s Planetary Defenders are observing the object, provisionally known as #A11pl3Z, right now using telescopes around the world.
— ESA Operations (@operations.esa.int) July 2, 2025 at 3:23 AM
Interstellar object candidate #A11pl3Z from Deep Random Survey, Chile (obs code X09). No obvious tail, will have to do a stack to see if there's anything…
Date is 2025 Jul 2 00:52:39 UTC.
— astrafoxen (@astrafoxen.bsky.social) July 1, 2025 at 8:30 PM
In the image above, the dot at center is the new candidate for an interstellar object visiting our solar system, currently named A11pl3Z.
UPDATE on our new interstellar friend #A11pl3Z:
Citizen scientist Sam Deen has found earlier observations of from June 25-28, from the ATLAS telescope!
Now with 6 days' worth of data, the eccentricity of A11pl3Z's trajectory is narrowed down to e=10.4 ± 1.1!
… that's undoubtedly interstellar.
???
— astrafoxen (@astrafoxen.bsky.social) July 1, 2025 at 9:37 PM
The orbit of the candidate interstellar object
Our friend at Atlas seem to have discovered the 3rd interstellar object deep in the milky way. Precovery data going back to June 25th is leaving little doubt. With an eccentricity near 10, this is like nothing seen before. Comet is screaming by us. ??
— David Rankin (@asteroiddave.bsky.social) July 1, 2025 at 9:25 PM
3rd interstellar object discovered? Maybe. There's a lot of buzz right now in the Astro community. More observations should come in tonight to confirm if A11pI3Z is from beyond the solar system.
— Tony Dunn (@tony873004.bsky.social) July 1, 2025 at 11:38 PM
Bottom line: We have a new interstellar object visiting our solar system! It’s likely a comet that’s speeding toward the sun and should make its closest approach in October 2025. Get finder charts here!
Kelly Kizer Whitt
About the Author:
Kelly Kizer Whitt - EarthSky’s nature and travel vlogger on YouTube - writes and edits some of the most fascinating stories at EarthSky.org. She's been writing about science, with a focus on astronomy, for decades. She began her career at Astronomy Magazine and made regular contributions to other outlets, including AstronomyToday and the Sierra Club. She has nine published books, including a children's picture book, Solar System Forecast, and a young adult dystopian novel, A Different Sky.
