NASA releases long-delayed, striking close-ups of Comet 3I/ATLAS, ending ‘alien’ theories — See images here

HiRISE on Mars Reconnaissance Orbiter imaged it on Oct 2. The comet was around 19 million miles from Mars then.

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 0.2 astronomical units (19 million miles, or 30 million kilometers) from the spacecraft. (Image: NASA/JPL-Caltech/University of Arizona)

What did solar probes record near the Sun?
STEREO followed the comet from Sept 11 to Oct 2. SOHO observed it between Oct 15 and Oct 26. Solar probes STEREO-A, SOHO and PUNCH tracked its motion. They watched it from Sept 28 to Oct 10 during its approach. The comet was 231–235 million miles from Earth then.

A faint image of comet 3I/ATLAS as observed by ESA/NASA’s SOHO mission between Oct. 15-16, 2025. The comet appears as a slight brightening in the center of the image. (Image: NASA/ESA/Lowell Observatory/Qicheng Zhang)

Which asteroid missions added distant high-resolution views?
Lucy captured images using L’LORRI on Sept 16. Psyche recorded multispectral views on Sept 8 and Sept 9.

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, 2025, 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. The L’LORRI imager captured the comet’s coma, the fuzzy halo of gas and dust surrounding 3I/ATLAS above, and its tail, a smudge of gas flowing to the right of the comet. This image spans about 11 arcminutes of sky, or roughly one-third the width of the full Moon. Solar system north is up. (Image: NASA/Goddard/SwRI/JHU-APL)

These spacecraft added sharp pictures from 33–240 million miles away. Webb will observe it in December for deeper composition data.

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 (53 million kilometers) 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 (shown in the zoomed-in inset image). (Image: NASA/JPL-Caltech/ASU)

What have scientists learned about its behaviour and makeup?
The comet moves at 30,000 mph through space. This speed is faster than any known Solar System comet. It holds carbon dioxide and water ice in large amounts. A strong nickel signal was also seen by scientists. This signal matches earlier findings from comet 2I/Borisov. Experts still cannot confirm the true size of the object. Dust hides the nucleus and limits direct measurement. Estimates range from several hundred metres to a few kilometres. The comet brightened strongly near perihelion on Oct 29. A faint visible-light tail also appeared at that time.

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.  (Image: NASA/Southwest Research Institute)

When will comet 3I/ATLAS pass closest to Earth?
NASA said the comet will pass nearest on Dec 19. The object will be 170 million miles from Earth then. This distance is nearly twice the span between Earth and the Sun.