Interstellar Comet 3I Atlas Sends First-Ever Radio Signal to Earth

Scientists have detected the first radio signal from an interstellar comet. The discovery was made on October 24, 2025, by the MeerKAT radio telescope in South Africa. The signal came from comet 3I Atlas, an object from beyond our solar system.

This marks a historic moment in astronomy. It provides the first direct chemical analysis of an interstellar visitor using radio astronomy. The findings confirm the comet’s alien origin and its active nature.

Decoding the Cosmic Message

The radio signal revealed specific hydroxyl molecules. These molecules are a key indicator of water sublimation from the comet’s icy core. The data showed clear absorption lines at 1,665 and 1,667 GHz.

According to Reuters, the signal strength was measured at -7.9 and -19.1 mJy km/s. This confirms the comet is actively releasing gases as it approaches the Sun. The velocity data perfectly matches a hyperbolic orbit, proving its interstellar journey.

This chemical fingerprint is crucial. It shows the comet contains water and other volatile compounds. These materials formed in a distant star system millions of years ago.

A Unique and Active Visitor

Comet 3I Atlas behaves differently from local comets. It exhibits strong non-gravitational acceleration. This means jets of gas are pushing it off a purely gravity-driven path.

Its nucleus is estimated to be up to 11 kilometers wide. That makes it significantly larger than ‘Oumuamua, the first known interstellar object. Recent images show a massive, structured ion tail and a distinct blue color.

The comet’s activity level surpasses that of comet Borisov, the second interstellar visitor. It has at least seven visible gas jets. Its surface appears highly volatile after eons in interstellar space.

Scientific Impact and Future Observations

The successful detection validates the power of radio astronomy. It provides a new method for studying the composition of interstellar objects without sending physical probes. This is a more efficient and far-reaching approach.

The scientific impact is profound. Researchers can now compare the building blocks of our solar system with those from another. This helps us understand how universal the processes of planet formation really are.

Future observations are already planned. NASA’s Juno spacecraft will listen for low-frequency radio emissions during the comet’s Jupiter flyby in March 2026. Ground-based telescopes will continue to monitor its activity and trajectory.

The detection of a radio signal from comet 3I Atlas opens a new window into the cosmos. It proves we can remotely study the chemistry of visitors from other star systems. This interstellar comet signal heralds a new era of galactic exploration.

Dropping this nugget your way

What is an interstellar comet?

An interstellar comet is a comet that originates from outside our solar system. It travels on a hyperbolic orbit, meaning it is not gravitationally bound to our Sun. 3I Atlas is only the third such object ever identified.

Can I see comet 3I Atlas from Earth?

It will not be visible to the naked eye. The comet’s closest approach to Earth is about 270 million kilometers. You would need a powerful telescope to have any chance of seeing it.

Why is the radio signal discovery important?

It allows for remote chemical analysis. Scientists can determine the comet’s composition without a costly space mission. This provides direct evidence of materials from another star system.

How is 3I Atlas different from ‘Oumuamua?

3I Atlas is a active comet, while ‘Oumuamua was a dormant asteroid-like object. This comet is much larger and is visibly outgassing, creating a distinct atmosphere and tail.

Where is the comet going next?

After its solar encounter, 3I Atlas will continue its journey out of our solar system. It will pass by Jupiter in 2026 before disappearing back into interstellar space.

What does this mean for the search for life?

It shows that the basic ingredients for life, like water, are common across the galaxy. Studying these objects helps us understand the distribution of prebiotic molecules in the universe.