New Close-Up Images Show Interstellar Comet 3I/ATLAS Brightening and Spraying Jets as It Heads Toward Earth

Comet 3I/ATLAS — the third confirmed interstellar object — is brightening and showing strong activity after a close pass by the Sun, and spacecraft around the solar system have captured some of the clearest images to date.

Recent Observations

Discovered in late June and confirmed in July as an interstellar visitor, 3I/ATLAS has been racing through the inner solar system at roughly 130,000 mph (210,000 km/h). The object made close approaches to Mars and the Sun in October and is scheduled to come closest to Earth on Dec. 19, when it will be about 170 million miles (270 million kilometers) away — roughly twice the Earth–Sun distance.

This week, both NASA and the European Space Agency (ESA) released fresh images showing that the comet's solar passage left it unusually bright and active, ejecting large amounts of sublimated gas and dust.

Hubble's View

On Dec. 4, NASA published an image taken by the Hubble Space Telescope on Nov. 30. The bright white spot at the image center shows the comet's nucleus and surrounding coma — the cloud of gas and dust that envelops the nucleus and feeds the tail. Because Hubble tracked the comet, background stars are elongated into streaks while the comet itself appears sharp.

Comets typically brighten as they approach the Sun: solar heating causes ices to sublimate, releasing gas that is carried away by solar radiation into a tail. The Sun-facing side of a comet can also produce jets of gas and dust erupting from warmer regions. Both an active coma and evidence of jetting are visible in Hubble's recent image.

JUICE's Closer Look

Also on Dec. 4, ESA released a view of 3I/ATLAS captured by the Jupiter Icy Moons Explorer (JUICE) probe on Nov. 2, just after the comet's near-Sun passage. JUICE was much closer to the comet than Hubble — about 41 million miles (66 million km) away — and its image shows a brimming, active comet.

"Not only do we clearly see the glowing halo of gas surrounding the comet known as its coma, we also see a hint of two tails," an ESA spokesperson wrote. "The comet's 'plasma tail' — made up of electrically charged gas — stretches out towards the top of the frame. We may also be able to see a fainter 'dust tail' — made up of tiny solid particles — stretching to the lower left of the frame."

JUICE observed the comet with five science instruments over two days. However, ESA says the probe's full dataset will not be transmitted to Earth until late February 2026 because JUICE must use its main antenna as a heat shield during the close solar pass and is temporarily relying on a smaller, lower-bandwidth antenna.

Size, Significance, And Ongoing Campaigns

Hubble's earlier observations in late July, though much fuzzier, helped constrain the object's size to roughly 1,400 feet (440 meters) to about 3.5 miles (5.6 kilometers) across — which would make 3I/ATLAS the largest interstellar object observed so far. New compositional and structural details from recent observations are expected as teams analyze the data.

Hubble and JUICE are just two of roughly a dozen missions and observatories that have targeted 3I/ATLAS from different vantage points, including Mars orbiters and rovers, solar-observing spacecraft, asteroid trackers, and ground- and space-based telescopes. The James Webb Space Telescope is scheduled to observe the comet again, and many professional and amateur astronomers will continue to track it as it approaches and recedes. Because 3I/ATLAS originated beyond our solar system, every additional image and spectrum helps scientists learn more about the composition and behavior of material from another star system.

Why It Matters

Interstellar objects offer rare, direct samples of material formed around other stars. Observing their brightness changes, jets, tails and composition helps researchers compare those materials to bodies that formed in our own solar system and improves our understanding of planetary formation processes across the galaxy.