3I/ATLAS Jets Pulsating Like A Heartbeat Every 16 Hours

New images of the interstellar object 3I/ATLAS reveal jets pulsating every 16 hours in a pattern that Harvard astronomer Dr. Avi Loeb compares to a heartbeat. According to his latest article published on Medium, this rhythmic behavior might not be coming from where scientists originally assumed.

When 3I/ATLAS was first detected on July 1st of this year, astronomers noticed its light was not steady. It was pulsating with a period of 16.16 hours, with brightness shifting by tens of percent with each cycle. Initially, researchers assumed this was caused by the nucleus of the object spinning, believing they were observing an elongated body tumbling through space. However, Dr. Loeb argues that explanation does not work.

According to Hubble Space Telescope images from July 21st, most of the light we see from 3I/ATLAS is not coming from the solid nucleus but from the coma, which is the glowing halo of gas and dust surrounding it. A study published from Cornell University back in August found the nucleus might be as small as 2.8 kilometers. If that is true, the nucleus reflects less than one percent of the total light at certain wavelengths. Dr. Loeb proposes an alternative explanation, suggesting the pulsating light is coming from the jets themselves, pumping material into the coma like a heartbeat.

Hubble Space Telescope images from July 21st

In a recent interview with Dobsonian Power, Dr. Loeb discussed what he calls one of the most significant anomalies yet. According to his calculations, 3I/ATLAS is on course to arrive at Jupiter at precisely the Hill radius distance, which is the boundary where Jupiter’s gravity dominates over the sun’s gravity. He noted this is a perfect match to four significant digits between the object’s closest approach to Jupiter and the Hill radius. The Lagrange points at this distance are exactly where satellites or probes would be placed to remain in stable orbit with minimal fuel requirements.

Dr. Loeb revealed that after he pointed out this coincidence in an essay on Medium and sent the link to David Farnocchia, who updates NASA’s JPL Horizons data on 3I/ATLAS, he received no response. Two days later, the numbers on the website were changed. According to Dr. Loeb, a key measurement called A1, which tracks how much the object speeds up or slows down from forces other than gravity, was reduced to almost one tenth of what it was before. Additionally, they switched the formula used to predict how the object behaves as it moves closer to or farther from the sun, going from a model based on water ice to one based on carbon dioxide.

Hill Radius diagram

Dr. Loeb also referenced a second object, R2 SWAN , which he believes could be on the borderline of being interstellar as well. What makes this interesting is that R2 SWAN travels almost perpendicular to the ecliptic plane, following a completely different orbital plane than 3I/ATLAS. According to Dr. Loeb, if you have a situation with a technological device, you would expect more than one, and very often one is used for distracting attention from the other.

The key distinction Dr. Loeb outlines is this: if 3I/ATLAS is a natural comet, those jets would point in the direction of the sun because that is what causes ice to sublimate. For a technological object, the direction would be arbitrary and would not need to align with the sun at all.

Per insights from the International Asteroid Warning Network website, hundreds of telescopes around the world will be observing 3I/ATLAS through a campaign running from November 27th through January 27th of 2026. The object will reach its closest approach to Earth on December 19th. Then on March 16th of next year, it will pass Jupiter at precisely the Hill radius distance, where NASA’s Juno spacecraft will be searching for low frequency radio signals during that encounter.

Sources

Are the jets from 3I/ATLAS pulsed like a heartbeat? (2025, November 30). Medium. https://medium.com/@avi-loeb/are-the-jets-from-3i-atlas-pulsed-like-a-heartbeat-fe39dc583d25

Dobsonian Power. (2025, November 27). AVI LOEB LIVE WITH US ON NEW 3I/ATLAS ANOMALIES! [Video]. YouTube. https://www.youtube.com/watch?v=WT4dSKZcysE

Gomez, C. (2025, November 28). 3I/ATLAS and R2 SWAN are behaving the same way. UFO News. https://www.ufonews.co/post/3i-atlas-and-r2-swan-are-behaving-the-same-way

Jewitt, D., Hui, M., Mutchler, M., Kim, Y., & Agarwal, J. (2025, August 4). Hubble Space Telescope observations of the interstellar interloper 3I/ATLAS. arXiv.org. https://arxiv.org/abs/2508.02934

MPEC 2025-U142 : Editorial Notice: Announcement of IAWN Comet Astrometry Campaign. (n.d.). https://www.minorplanetcenter.net/mpec/K25/K25UE2.html