Interstellar comet 3I/ATLAS will soon make it's closest approach to Earth by Dec. 19 as it visits our solar system.
The High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA’s Mars Reconnaissance Orbiter captured this image of interstellar comet 3I/ATLAS on Oct. 2, 2025. At the time it was imaged, the comet was about 19 million miles from the spacecraft.
A faint image of comet 3I/ATLAS as observed by ESA/NASA’s SOHO mission between Oct. 15-26, 2025. The comet appears as a slight brightening in the center of the image.
The interstellar comet 3I/ATLAS, circled in the center, as seen by the L’LORRI panchromatic, or black-and-white, imager on NASA’s Lucy spacecraft. This image was made by stacking a series of images taken on Sept. 16, as the comet was zooming toward Mars. Lucy was 240 million miles away from 3I/ATLAS at the time making its way to explore eight asteroids that share an orbit with Jupiter.
This image shows the 3I/ATLAS interstellar comet as a bright, fuzzy orb in the center. Traveling through our solar system at 130,000 miles (209,000 kilometers) per hour, 3I/ATLAS was made visible by using a series of colorized stacked images from Sept. 11-25, using the Heliocentric Imager-1 (H1) instrument, a visible-light imager on the STEREO-A (Solar Terrestrial Relations Observatory) spacecraft. The colorization was applied to differentiate the image from other observing spacecraft images.

A comet that is likely much, much older than our solar system has spent months traipsing through Earth's cosmic neighborhood. And at long last, NASA has unveiled an unprecedented look at the object, named 3I/ATLAS.

And no, it's not an alien spaceship.

A trove of photos the U.S. space agency dropped reveal fascinating new characteristics of 3I/ATLAS, which has captured the public's attention since it was first spotted at the beginning of July by a ground telescope in Chile. The visitor, which is on an unusual trajectory taking it momentarily through our solar system, has made waves as just the third-ever interstellar interloper originating from another star discovered in our backyard.

The object, which astronomers agree is a comet, also hasn't been able to shake a persistent conspiracy theory that it could be extraterrestrial technology. But during a Wednesday, Nov. 19, news conference, NASA officials dismissed such speculation.

Here's everything to know about 3I/ATLAS, along with a look at NASA's new photos.

What is 3I/ATLAS?

An object known as 3I/ATLAS made news in July when it was confirmed to be the third-ever object discovered originating outside Earth's solar system. When it was spotted, 3I/ATLAS was whizzing at about 137,000 miles per hour, according to NASA.

Observations of 3I/ATLAS's speed and trajectory confirmed to astronomers that it formed in another star system and was ejected into interstellar space – the region between the stars, according to NASA. For potentially billions of years, the comet has drifted on a journey from the general direction of the constellation Sagittarius in the center of the Milky Way that recently brought it into our solar system.

See new photos of interstellar comet 3I/ATLAS

NASA on Wednesday, Nov. 19, released a trove of never-before-seen images of 3I/ATLAS unveiling new characteristics of the object.

A look at all of the photos NASA has released of 3I/ATLAS since its July discovery, including detailed explanations of each, are available by clicking through the below gallery.

NASA unveils never-before-seen 3I/ATLAS images in press conference

Unlike comets bound to the sun's gravity, 3I/ATLAS is traveling on a hyperbolic orbit that will eventually carry it out of the solar system and back into interstellar space. That's why the world's astronomers and space agencies are racing to study planetary material that formed from another star.

A fleet of NASA space telescopes – including the Hubble Space Telescope and the James Webb Space Telescope – have already months ago returned images and data back to Earth gathered from glimpsing the comet.

NASA's latest images, which made their debut during the U.S. space agency’s press conference, offer new perspectives on 3I/ATLAS as captured by a fleet of both ground and space instruments.

The closest look at the comet came from NASA's spacecraft orbiting Mars when 3I/ATLAS came within 19 million miles of the red planet at the beginning of October. Even the Perseverance rover spotted a faint glimpse of the object from the Martian surface.

Some of NASA’s heliophysics missions, which are centered around the sun, also tracked the comet in September and October when it passed behind the sun, obscuring it temporarily from Earth as it came no closer than 130 miles. Though NASA's solar missions have previously observed and discovered thousands of comets from Earth's solar system, this is the first time those missions have purposefully observed an object originating from another star, NASA said.

Two NASA spacecraft on their way to study asteroids on the outskirts of our solar system – Psyche and Lucy – also took the time amid their journeys to glimpse 3I/ATLAS. Psyche's observations, acquired from 33 million miles away, will help scientists refine the comet’s trajectory, while Lucy's images from 240 million miles away reveal details of the comet’s coma and tail.

Plenty more observations are on the way as 3I/ATLAS approaches Earth and then heads toward Jupiter in 2026.

"By observing the comet from so many locations, NASA has an opportunity to learn about the ways that 3I/ATLAS differs from our solar system’s home-grown comets," NASA said in a blog post unveiling the photos, "and give scientists a new window into how the compositions of other systems may differ from our own."

Is 3I/ATLAS an alien spaceship? NASA leaders reject conspiracy theory

The strange outsider's jaunt through Earth's cosmic neighborhood has sparked plenty of outlandish conspiracy theories regarding its nature.

One particularly infamous idea – put forth by a Harvard astrophysicist named Avi Loeb – is that 3I/ATLAS could be an alien spaceship. Though Loeb has conceded on publishing platform Medium that the object is "most likely a comet of natural origin," he has not ruled out the possibility that it could be extraterrestrial technology.

NASA officials, though, attempted to put that notion to rest.

"It's natural to wonder what it is. We love that the world wondered along with us," Nicola Fox, associate administrator of NASA's Science Mission Directorate, said during a news briefing in Greenbelt, Maryland, as reported by Reuters. "We were quick to be able to say, 'Yup, it definitely behaves like a comet. We certainly haven't seen any technosignatures or anything from it that would lead us to believe it was anything other than a comet."

How big is 3I/ATLAS?

Astronomers don’t yet know exactly how big 3I/ATLAS could be, but estimates range from a few hundred feet to a few miles across, according to the European Space Agency. Data returned from Hubble allowed astronomers to estimate the size of the comet’s solid, icy nucleus as anywhere from about 1,400 feet to 3.5 miles wide.

When will 3I/ATLAS pass by Earth?

The comet 3I/ATLAS, which is not a threat to Earth, is projected to pass within about 170 million miles of our planet on Dec. 19 – or about twice the distance between Earth and the sun.

Contributing: Reuters

Eric Lagatta is the Space Connect reporter for the USA TODAY Network. Reach him at elagatta@gannett.com

This article originally appeared on USA TODAY: What is NASA saying about 3I/ATLAS? Officials reject alien spaceship theory

Reporting by Eric Lagatta, USA TODAY / USA TODAY

USA TODAY Network via Reuters Connect