The first radio signal from comet 3I/Atlas would confirm its origin

The comet 3I/Atlas made headlines again after the detection of its first radio signal. According to information released by The Astronomer’s Telegram, what was recorded by the South African radio telescope MeerKAT is not technological at all: these are OH molecules, a typical marker of cometary activity.

The discovery reinforces the scientific position that 3I/Atlas is a natural comet, not an artificial object or a spacecraft. The detection provides a key piece to close the debate, although the public discussion promises to remain active.

What exactly did MeerKAT detect?

MeerKAT, a radio telescope composed of 64 antennas, recorded absorption lines of hydroxyl radicals (OH) at frequencies of 1665 MHz and 1667 MHz. This is typical behavior in comets approaching the Sun, where they sublimate ice and release water into space.

These lines appear in absorption due to the comet's position relative to the Sun. The sublimation of ice alters the trajectory and generates these radio signatures.

OH: the molecule that confirms the comet's nature

The hydroxyl radical can absorb or emit radiation at specific frequencies. It is a frequent signal in nebulae, star-forming regions, and comets. Its presence in 3I/Atlas fits perfectly with the expected behavior for a naturally occurring object.

The detection was made on October 24, five days before perihelion. Previous attempts, on September 20 and 28, had not been successful.

What does Avi Loeb, proponent of the technological hypothesis, say?

The Harvard astrophysicist Avi Loeb acknowledged that so far "no radio detection has been reported."

Even so, he doesn't rule out continuing the investigation. He indicated that the spacecraft Juno could search for signals between 40 and 50 MHz when the comet passes near Jupiter in March 2026, which will keep the discussion active.

Are conspiracy theories coming to an end?

The scientific evidence is increasingly clear: 3I/Atlas behaves like a comet in full solar activity.

For astronomy, the detection is good news. It allows researchers to study how the object evolves and map its OH production as it moves toward its closest point to Earth.