3I/ATLAS Hurtling Through Solar System Could Be As Big As Manhattan

[Buster's Uncle]

Mysterious Interstellar Object Hurtling Through Solar System Could Be As Big As Manhattan
Matthew DeBord
Jalopnik
Sat, October 4, 2025 at 3:05 PM EDT
3 min read



Object 3I/ATLAS as captured by the Hubble Space Telescope - NASA


It's probably a comet, but it might be some sort of ancient alien spacecraft or probe. What's for sure is that the mystery surrounding an object known as 3I/ATLAS is becoming both more and less...mysterious as it flies through our neighborhood of the galaxy. Here's the latest from New York Post:

Scientists have discovered that the 3I/ATLAS — a Manhattan-sized interstellar object that potentially has alien tech — is much larger than previously thought.... First discovered by NASA on July 1, the cosmic anomaly has been under watch by Harvard astrophysicist Avi Loeb and his team as it shoots across the solar system.

Loeb has been courting both controversy and a touch of nerdy celebrity ever since 3I/ATLAS was spotted. Building on his suggestion that a previous visitor, dubbed "Oumuamua," could have been some sort of spacecraft, Loeb has been speculating the 3I/ATLAS is more of the same. In a recent Medium post, Loeb summarized a new paper he co-authored that discusses just how unexpectedly freaking big 3I/ATLAS could be: 33 billion tons, with a width of three miles!


Anomalously enormous


An image showing the first detection on 3I/ATLAS in July - NASA


As the Post notes, Loeb is preoccupied with this thing's size. He suspects its bigness is galactically abnormal, somewhat fueling his hypothesis that it could be something other than an enormous comet: "Given the limited reservoir of heavy elements, we should have discovered on the order of a hundred thousand interstellar objects on the 0.1-kilometer scale of 1I/`Oumuamua before finding 3I/ATLAS, yet we only detected two interstellar objects previously."

Thanks to a spacecraft currently orbiting Mars, on October 3 we should be able to get a closer look at 3I/ATLAS as a it zooms by (it isn't going to collide with Earth, but it will be passing through the Sun's glare when more direct observation from our planet would be possible, so we're not going to get a close-up, although we will be able to check it out later as it passes Jupiter). For his part, Loeb will be on the lookout for any changes in the object's flight path, writing that "a future detection of a major maneuver of 3I/ATLAS would suggest propulsion by a technologically manufactured engine." NASA has provided a helpful animation that shows the object's trip through the solar system and how close it's coming to Mars, Venus, and Jupiter.


We are maybe not alone?


A graphic depicting 3I/ATLAS's journey through the solar system - NASA


We'll soon have a better idea of what, exactly, 3I/ATLAS is and isn't. Two things have been simultaneously transpiring since it was first located. First, there has been some real-time astronomy taking place, and it's been fascinating to see the science at work. Second, Loeb – for all his self-promotional skills – has generated an intriguing narrative about why these recent interstellar visitors are so curious. If we aren't alone in the universe, it's reasonable to expect that some evidence of alien intelligence might show up at some point.

All that said, 3I/ATLAS is probably just a really big comet. Once it completes its journey through the solar system, it will obviously continue on its trajectory and perhaps visit some other regions of space. If anyone lives there, and they have the equivalent of our Earth tech, they might be equally intrigued and baffled. It does kind of make you wish the aliens could be a bit more obvious in their approach.

Read the original article on Jalopnik.