3I/ATLAS to make its closest approach to Earth in December. Here's the latest

December 02, 2025 Neo
3I/ATLAS to make its closest approach to Earth in December. Here's the latest

December is the month thatfans of the 3I/ATLAS interstellar comethave been waiting for.

In a matter of days, thestrange space object that has become a cultural phenomenonis due to get as close to Earth as it ever will.

If you're a professional or amateur astronomer, that means it'll be among yourbest opportunities to catch a glimpse of an ancient objectcomposed of planetary material that formed from another star. And if you're among those buying into theconspiracy theory that 3I/ATLAS could be extraterrestrial technology, that may be the day of the alien invasion – or something?

No, 3I/ATLAS is not an incoming spaceship – at least, according tothe consensus of astronomers and the world's space agencies. But it still isn't very often that an object from outside Earth's solar system finds its way into our cosmic neighborhood.

The multi-colored tracks of asteroids flash on and off in this image of two spiral galaxies within the Virgo Cluster. Each of these tracks represents a moving asteroid detected by NSF–DOE Vera C. Rubin Observatory in its first few nights of observations. The open star cluster Bochum 14 as imaged by NSF–DOE Vera C. Rubin Observatory. Aerial view of Vera C. Rubin Observatory located in Chile, taken Jan. 24, 2024. Surrounded by desert-like mountains and under the blue skies of northern Chile, the Vera C. Rubin Observatory will revolutionize the study of the universe when it incorporates the largest digital camera ever built in the world. (Photo by) (Photo by JAVIER TORRES/AFP via Getty Images) Rubin Observatory stands on Cerro Pachón in Chile against a sky full of star trails in this long exposure night sky image. Sunset at Rubin Observatory on Cerro Pachón in Chile. NSF–DOE Vera C. Rubin Observatory atop Cerro Pachón in Chile is outlined against the full Moon rising above the horizon. A trick of perspective has enlarged the Moon beyond the size we'd naturally see it on Earth. Rubin Observatory will begin science operations in late 2025. This image captures not only Vera C. Rubin Observatory, but one of the celestial specimens Rubin Observatory will observe when it comes online: the Milky Way. The bright halo of gas and stars on the left side of the image highlights the very center of the Milky Way galaxy. The dark path that cuts through this center is known as the Great Rift, because it gives the appearance that the Milky Way has been split in half, right through its center and along its radial arms. This image combines 678 separate images taken by NSF–DOE Vera C. Rubin Observatory in just over seven hours of observing time. Combining many images in this way clearly reveals otherwise faint or invisible details, such as the clouds of gas and dust that comprise the Trifid nebula (top) and the Lagoon nebula, which are several thousand light-years away from Earth. This image captures a small section of NSF–DOE Vera C. Rubin Observatory's view of the Virgo Cluster, offering a vivid glimpse of the variety in the cosmos. Visible are two prominent spiral galaxies, three merging galaxies, galaxy groups both near and distant, stars within our own Milky Way, and much more. Made from over 1100 images captured by NSF-DOE Vera C. Rubin Observatory, this image contains an immense variety of objects. This includes about 10 million galaxies, roughly .05% of the approximately 20 billion galaxies Rubin Observatory will capture in the next decade. This image captures a small section of NSF–DOE Vera C. Rubin Observatory's view of the Virgo Cluster, revealing both the grand scale and the faint details of this dynamic region of the cosmos. Bright stars from our own Milky Way shine in the foreground, while a sea of distant reddish galaxies speckle the background.

Vera C. Rubin Observatory reaches for the stars: Take a look

Here'severything to know about 3I/ATLAS' impending rendezvous with Earth andhow you might be able to witness it.

What is 3I/ATLAS?

The 3I/ATLAS interstellar comet is approaching Earth and will on Dec. 19 fly within 170 million miles of our planet.

An object known as3I/ATLASmade news in July 2025 when it wasconfirmed 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' speed and trajectoryconfirmed to astronomers that it formed in another star system and was ejected into interstellar space – the region between the stars, according toNASA. For potentially billions of years, the comet has drifted on a journey from the general direction of the constellation Sagittarius in the center ofthe Milky Waythat recently brought it into our solar system.

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.

How big is 3I/ATLAS?

Astronomersdon'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 theEuropean Space Agency. Datareturned from the Hubble Space Telescopeallowed astronomers to estimate the size of the comet's solid, icy nucleus as anywhere from about 1,400 feet to 3.5 miles wide.

Where is 3I/ATLAS now? Interstellar comet approaches 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.

The object alsocame within 130 million miles of the sunon Oct. 30, just inside the orbit of Mars. For reference, the sun is about 93 million miles away from Earth.

Can I see 3I/ATLAS from the ground? Where can I track its position?

Though 3I/ATLAS is not visible to the naked eye, those with even a small telescope can observe the comet in the pre-dawn sky until spring 2026, according to NASA. The agency's "Eyes on the Solar System" online simulation shows the current location and path of 3I/ATLAS as it moves through our solar system.

NASA releases photos of 3I/ATLAS comet

NASA on Nov. 19released a trove of never-before-seen imagesof 3I/ATLAS unveiling new characteristics of the object. The imagery came courtesy of the space agency's fleet of space telescopes and other spacecraft that have spent months observing the comet.

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

NASA's Psyche mission acquired four observations of interstellar comet 3I/ATLAS over the course of eight hours on Sept. 8 and 9, 2025, when the comet was about 33 million miles from the spacecraft. The data, captured by Psyche's multispectral imager, is helping astronomers both refine the trajectory of 3I/ATLAS and learn more about the faint coma, or cloud of gas, surrounding its nucleus. This image shows the observation of comet 3I/ATLAS when it was discovered on July 1, 2025. The NASA-funded ATLAS survey telescope in Chile first reported that the comet originated from interstellar space. 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. This image shows the halo of gas and dust, or coma, surrounding comet 3I/ATLAS, the third interstellar object ever detected by astronomers as it passes through our solar system. The image was taken on Oct. 9, 2025, by an instrument onboard NASA's MAVEN spacecraft, which has been studying Mars from its orbit since 2014. The instrument, the Imaging Ultraviolet Spectrograph, takes pictures in the ultraviolet part of the spectrum to reveal the chemical composition of objects. 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. An ultraviolet image composite of the hydrogen atoms surrounding comet 3I/ATLAS, the third interstellar object ever detected by astronomers, as it passes through our solar system. This image was taken on Sept. 28, just days before the comet's closest approach to Mars - by an instrument on NASA's MAVEN spacecraft, which has been studying Mars from orbit since 2014. Comet 3I/ATLAS appears as a bright object near the center of this image, made from combining observations from NASA's PUNCH mission taken from Sept. 20 to Oct. 3, 2025, when the comet was about 231 million to 235 million miles from Earth. Its tail appears as a short elongation to the right. Stars appear as streaks in the background. 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. NASA's SPHEREx space telescope observed interstellar comet 3I/ATLAS from Aug. 7 to Aug. 15. Hubble captured this image of the interstellar comet 3I/ATLAS on July 21, 2025, when the comet was 277 million miles from Earth. Hubble shows that the comet has a teardrop-shaped cocoon of dust coming off its solid, icy nucleus. NASA's James Webb Space Telescope observed interstellar comet 3I/ATLAS Aug. 6, with its Near-Infrared Spectrograph instrument

NASA's fleet of telescopes, spacecraft glimpse 3I/ATLAS. See photos of interstellar comet

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/ATLAScould 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, have attempted to put that notion to rest.

In a social media exchangewith reality TV star Kim Kardashian in October, NASA Acting Administrator Sean Duffy affirmed: "No aliens. No threat to life here on Earth."

Nicola Fox, associate administrator of NASA's Science Mission Directorate, also rejected the alien conspiracy theory during the agency's November news conference, saying "we certainly haven't seen any technosignatures or anything from it that would lead us to believe it was anything other than a comet."

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:Interstellar comet 3I/ATLAS heads toward Earth. How close will it get?

 

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