Comet 3I/ATLAS’ upcoming encounter with the sun could change it in big ways — Space photo of the week

The interstellar comet 3I/ATLAS was spotted hurtling through the solar system on Aug. 27 by the Gemini South telescope stationed in Chile.(Image credit: International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the ScientistImage Processing: J. Miller & M. Rodriguez (International Gemini Observatory/NSF NOIRLab), T.A. Rector (University of Alaska Anchorage/NSF NOIRLab), M. Zamani (NSF NOIRLab))KEY DETAILS

What it is: The interstellar comet 3I/ATLAS, sporting a tail that continues to grow

Where it is: Deep within the inner solar system, rushing in the direction of the Red Planet

When it was presented: Sept. 4, 2025

Even as a dazzling comet, visible to the unaided eye, passes across Earth’s skies (hats off to Comet Lemmon!), the most notable object in the solar system at present remains unseen, concealed on the other side of our sun: the interstellar comet 3I/ATLAS.

This extraterrestrial guest, considered by a majority of astronomers to be a comet stemming from an uncharted star system situated far from our own, is only the third such interstellar body ever registered within our solar system. It stands as the largest, the fastest-moving, and most likely the most ancient interstellar entity to have been observed.

Although it was recently verified by NASA in early July, this unrestrained sphere of ice and dust is progressing toward the midpoint of its journey throughout our solar system. This Wednesday (Oct. 29), 3I/ATLAS will arrive at perihelion — its closest approach to the sun — before initiating its months-long departure from our cosmic neighborhood.

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A modified iteration of the picture ‘freezes’ the backdrop stars in position while 3I/ATLAS advances through the center.

We will miss this interstellar visitor, but at least we can always look back on the photographs. The image displayed above, documented on Aug. 27 by the Gemini South telescope in Chile, an establishment overseen by the National Science Foundation, may offer the most refined depiction to date. As 3I/ATLAS approaches the sun more closely, radiation emitted from our star warms the ice present on the comet’s body (the nucleus), triggering ejections of gas and dust that consequently create a shimmering aura (a coma) surrounding it. The push exerted by our star’s perpetual solar winds propels this material into forming a lengthy, noticeable tail oriented away from the solar body.

As 3I/ATLAS gets to perihelion this week — drawing within 1.4 astronomical units, or 130 million miles (210 million kilometers) of the sun, as per NASA’s estimations — it could escalate its gas emissions markedly. Upon the comet’s re-emergence into telescope visibility in early November, it might exhibit both enhanced size and luminosity relative to its appearance two months prior. Instruments situated on the ground, in orbit, and those en route to Jupiter will focus intently, elevating 3I/ATLAS’s status as a space celebrity as it forever departs our solar system.

Studying this interstellar comet with the comprehensive capabilities of humankind’s astronomical devices could potentially unveil countless revelations concerning our galaxy’s outer reaches and its enigmatic past. In the meantime, all that remains is to observe, enjoy the sun’s warmth, and understand that a store of cosmic insights is within reach, just beyond our own star.

For even more exquisite space imagery, delve into our Space Photo of the Week archives.

TOPICSspace photo of the week

Brandon SpecktorSocial Links NavigationEditor

Brandon serves as the space/physics editor at Live Science. His publications include pieces in The Washington Post, Reader’s Digest, CBS.com, the Richard Dawkins Foundation website, and various other sources. He earned a bachelor’s degree in creative writing from the University of Arizona, complemented by minors in journalism and media arts. He derives the most satisfaction from writing about space, geoscience, and the enigmas of the universe.

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