Interstellar Comet 3I/ATLAS: Hubble’s Sharpest Snapshot of a Cosmic Visitor

Updated on Aug 11, 2025 | By Jameswebb Discovery Editorial Team 

In a discovery that has astronomers and space enthusiasts buzzing, the Hubble Space Telescope has captured its clearest-ever image of Interstellar Comet 3I/ATLAS—a rare traveler from beyond our Solar System. Moving at an astonishing 130,000 miles per hour (about 210,000 kilometers per hour), this icy wanderer is only the third confirmed interstellar object ever spotted, following ʻOumuamua in 2017 and Comet 2I/Borisov in 2019.

A Once-in-a-Lifetime Visitor

3I/ATLAS was first detected on July 1, 2025, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey in Chile. Its unusual speed and hyperbolic trajectory—meaning it will never return—confirmed its interstellar origin. For scientists, that makes 3I/ATLAS a priceless opportunity to study material from another star system without leaving our own.

Unlike most comets that orbit our Sun, 3I/ATLAS is on a one-way trip, passing through our Solar System before heading back into interstellar space forever.

Hubble’s Record-Breaking Image

Hubble’s newly released image shows a spectacular teardrop-shaped dust plume streaming from the comet’s nucleus, which scientists estimate to be between 320 meters and 5.6 kilometers in diameter. The clarity of the image allows researchers to study the comet’s composition, structure, and activity in unprecedented detail.

NASA notes that the precision of Hubble’s optics made it possible to detect faint features that ground-based telescopes could not capture. This is particularly important for interstellar comets, as they may carry clues about the early chemistry of other star systems.

Speed and Trajectory

Traveling at over 130,000 mph relative to the Sun, 3I/ATLAS is one of the fastest objects ever observed passing through our Solar System. It will reach its closest approach to the Sun—known as perihelion—on October 29–30, 2025, when it will pass near the orbit of Mars.

After perihelion, the comet will swing behind the Sun from Earth’s perspective, becoming unobservable until early December 2025. By then, it will already be heading back into deep space, never to be seen again.

Why 3I/ATLAS Matters

Studying an object like 3I/ATLAS gives scientists a rare window into the makeup of distant planetary systems. The comet’s dust and gas may contain molecules and isotopes that are subtly different from those found in comets born in our own Solar System.

Some researchers have even suggested that analyzing this material could help us understand the conditions that lead to planet formation and possibly life itself.

The Alien Hypothesis

Adding to the intrigue, Harvard astronomer Avi Loeb has publicly suggested that 3I/ATLAS could be an artificial object—perhaps an alien probe—due to its unusual speed and trajectory. While the vast majority of scientists believe it is a natural comet, Loeb argues that the possibility should be investigated before the comet is gone for good.

This speculation has stirred both excitement and skepticism in the scientific community, but it undeniably adds to the public fascination surrounding this interstellar visitor.

Can the James Webb Space Telescope Join the Hunt?

While Hubble has provided the sharpest view yet, the James Webb Space Telescope (JWST) could offer complementary data by capturing infrared spectra of 3I/ATLAS. This would allow scientists to detect the molecular fingerprints of the comet’s ices and dust, revealing details about its origin and chemical composition.

If observation time is approved, JWST’s infrared sensitivity could make 3I/ATLAS one of the most thoroughly studied interstellar visitors in history.

How to See 3I/ATLAS

Although it will not be bright enough to see with the naked eye, amateur astronomers with moderate to large telescopes may be able to spot the comet in the weeks leading up to its October perihelion. Skywatchers should look for updated star charts from astronomy organizations as the date approaches.

The Clock Is Ticking

Interstellar Comet 3I/ATLAS offers a fleeting opportunity to study the building blocks of distant star systems without sending a spacecraft across light-years of space. By the time it disappears from view, it will take with it secrets from a world far beyond our own.

For now, both professional and amateur astronomers are racing against the clock to collect as much data as possible on this rare and mysterious traveler.