Scientists Pick Up First Radio Signal Traced Directly to a Planet Beyond Our Solar System

A Cosmic First: Radio Waves From Another World

For many years, astronomers have listened for the radio crackle of planets beyond the Solar System. They may have finally isolated one. The source is Beta Pictoris b, a young gas giant about 64 light-years away. A team from the Center for Astrophysics Harvard & Smithsonian and the University of Oregon has announced the landmark first: a radio signal coming directly from an exoplanet — a planet outside the Solar System.

Despite what "radio signal from an exoplanet" may suggest, this is not a message from aliens. The signal appears to come from an aurora — the same broad family of magnetic phenomena that produces Earth's beautiful northern and southern lights and Jupiter's powerful radio bursts. Still, the discovery is anything but ordinary. The radio waves also reveal the planet's magnetic field, making this potentially the first direct detection of the magnetic field of an exoplanet.

How the Signal Was Found

Using South Africa's MeerKAT array, researchers observed the Beta Pictoris system four times in 2025 and 2026. Each time, they picked up radio emission, including short bursts that brightened and faded rapidly. The signal spanned a broad range of radio frequencies and had an especially revealing property: much of it was circularly polarized, meaning the radio waves corkscrewed through space rather than oscillating in a single direction.

The team detected bursts of radio wave energy spanning from 0.85 to 3.5 GHz, which were strongly circularly polarized and repeated very frequently — characteristic features of the Electron Cyclotron Maser Instability, the same mechanism responsible for producing auroral radio waves on both Earth and Jupiter. Radio detections from planet-hosting systems have previously been difficult to attribute directly to an exoplanet rather than its host star. In this case, the researchers say they were able to localize the emission to Beta Pictoris b with a high degree of certainty.

What It Tells Us About the Planet

Beta Pictoris b is a huge, hot planet similar to Jupiter that orbits a bright star called Beta Pictoris, located approximately 63 light-years from Earth. At about 20 million years old, this planet is relatively young and is currently emitting light as a result of the heat created during its formation. Researchers calculated the strength of the magnetic field of the planet to be at least 1.25 kilogauss based on the highest frequency detected.

It seems Beta Pictoris b has a particularly strong magnetic field, which fits in with previous modeling of the planet and its dynamo — the internal processes that generate the magnetic field. The high magnetic field that exists on Beta Pictoris b could potentially be related to both its youthfulness and fast rotation rate, providing insight into the development of planetary dynamos.

Why This Matters for the Search Beyond Our Solar System

For years, astronomers have suspected that planets beyond our Solar System might host magnetic fields that shape their atmospheres and shield them from stellar winds. But until now, no one had directly measured one. Magnetic fields are considered a critical ingredient for planetary habitability — Earth's own field deflects harmful solar radiation, helping to protect life on the surface. Being able to detect and measure them from tens of light-years away is a profound leap forward.

The study, posted September 15 as an arXiv preprint and not yet peer-reviewed, would mark both the first radio emission securely localized to an exoplanet and the first direct measurement of an exoplanet's magnetic-field strength. The researchers describe the result as the first direct measurement of magnetic-field strength for an exoplanet, saying it is consistent with dynamo-scaling predictions for a young, massive giant planet. As peer review proceeds and more observations accumulate, this technique could become a powerful new tool for understanding distant worlds — and, eventually, for identifying which ones might be capable of supporting life.