The first radio signal from Comet 3I/Atlas ends the debate about its nature

She has more evidence appeared to support the natural origin of Comet 3I/ATLAS. After several weeks of conspiracy theories, debate on social media, and speculation on popular podcasts like The Joe Rogan Show, this interstellar object has been discovered. Still guilty. The latest confirmation came from an observatory in South Africa that detected the first radio signal from 3I/Atlas.

But how? Radio signal? That should confirm that the body is technological in nature, right? The thing is, this is not a radio signal like a transmission emitted by a spacecraft. It is instead a radio frequency pattern detected by MeerKAT, a radio telescope made up of 64 antennas – each 13.5 meters in diameter – operated by the Radio Astronomy Observatory in South Africa. What did you reveal? “OH absorption was detected on the 1665 MHz and 1667 MHz lines,” according to Researchers.

What Meerkat specifically discovered were radio absorption lines by hydroxyl radicals, i.e. OH molecules, a pattern that would be consistent with typical comet activity. The lines appear as absorption because 3I/Atlas was so close to the Sun and the observational geometry favors absorption over emission. This is the phenomenon that was explained in WIRED a few days ago when the controversy over gravitational acceleration arose: when comets reach their closest approach to the Sun, they sublimate ice into space and receive a greater amount of radiation. This also changes their course.

The hydroxyl radical (OH) can absorb or emit radiation at specific frequencies (such as the 1665 and 1667 MHz lines) due to shifts in its energy levels. These OH spectral lines have been detected in nebulae, comets, and star-forming regions. OH helps astronomers map the universe’s stellar and water regions because it can “glow” brightly at radio frequencies under certain conditions.

Is there still hope that it is more than just a comet?

The discovery was made possible on October 24, five days before 3I/Atlas made its closest approach to the Sun. MeerKAT had tried to detect radio signals earlier, on September 20 and 28, although it was unsuccessful. “Five weeks ago, radio observatories like MeerKAT were encouraged to search for radio transmissions from 3I/ATLAS since the arrival direction of 3I/ATLAS coincides by 9 degrees with the satellite’s arrival direction. amazing! signal “It was discovered in 1977 at a frequency of 1.4204556 gigahertz,” astrophysicist Avi Loeb wrote in Medium mail. “In response, I was assured that 3I/ATLAS would be monitored by radio observatories such as MeerKAT.”

“No radio detection of 3I/ATLAS has been reported to date, other than an OH absorption signal,” Loeb admitted. Of course, continuous monitoring of the body must be performed to determine whether OH production is constant or intermittent, along with factors such as the extent and structure of the tail, to reach more solid conclusions about its nature.

Loeb has been among the most vocal advocates of the hypothesis that 3I/Atlas has a technological origin. (And he Kim Kardashian has already been invited To join his research team.). Meerkat’s findings did not dampen his quest to explore the nature of the comet. “On March 16, 2026, 3I/ATLAS is expected to pass within 53 million kilometers of Jupiter. At that time, the Juno spacecraft will use its dipole antenna to search for a radio signal from 3I/ATLAS at low frequencies in the 50 Hz to 40 MHz range,” he wrote.

Will the discovery of MeerKAT be enough to put an end to conspiracy theories about 3I/Atlas? Probably not, and at least the discussions have increased the general public’s awareness of and interest in astrophysics. In the meantime, you can relive the path of Comet 3I/ATLAS here. And do not forget to mark December 19 in the calendar, the date on which the interstellar guest will reach the closest point to Earth.

This story first appeared on WIRED in Spanish It was translated from Spanish.