It may already be on its outward journey, slipping past Earth and heading back towards interstellar space, but the comet 3I/ATLAS is still rewriting what scientists know about visitors from beyond our solar system. New observations show that this rare interstellar comet produced strange, wobbling jets inside an even rarer feature: a tail that points towards the Sun.Comets are usually defined by their glowing comas and sweeping tails of gas and dust, driven away from the nucleus as sunlight heats and vaporises icy material. Those tails almost always stream in the opposite direction of the Sun, pushed outward by solar radiation and the solar wind. An “anti-tail,” however, defies that rule by appearing to point sunward. Such structures are uncommon, short-lived, and usually difficult to study in detail.In the case of 3I/ATLAS, researchers found that this Sun-facing tail contained jet-like structures that did not remain fixed. Instead, they slowly shifted position, wobbling with a regular rhythm. In some observations, the anti-tail itself appeared to stretch as far as about 620,000 miles, or roughly 1 million km, making it an unexpectedly prominent feature for such a distant and fleeting object.Also read | Comet 3I/ATLAS, from beyond the Solar System, found carrying key molecule linked to lifeWhat makes the discovery particularly striking is the comet’s origin. 3I/ATLAS is only the third known object confirmed to have entered our solar system from elsewhere in the galaxy. The first was the enigmatic, cigar-shaped object Oumuamua, detected in 2017, followed by the interstellar comet 2I/Borisov in 2019. While comets born within the solar system have previously shown anti-tails and even wobbling jets, this is the first time scientists have seen this kind of outgassing behaviour in a visitor from another star.“Characterising jets in 3I thus represents a rare opportunity to investigate the physical behaviour of a pristine body formed in another planetary system,” the research team wrote in a paper describing the findings.The finding occurred following a rigorous observation effort that lasted 37 nights, from July 2 to September 5, 2025. The group operated the Two-meter Twin Telescope (TTT), an automated observatory situated at the Teide Observatory in Tenerife, within Spain’s Canary Islands. During that time, the comet’s appearance transformed significantly as it approached the Sun.Early observations showed a fan-shaped distribution of dust in the coma that pointed towards the Sun. As weeks passed, this feature transformed into a more pronounced tail extending in the opposite direction. According to the researchers, this shift reflects the growing influence of solar radiation on the dust surrounding the nucleus as 3I/ATLAS approached its closest point to the Sun on October 30, 2025, when it passed within about 130 million miles, or 210 million km, of our star.Story continues below this adWithin this evolving structure, the jet feature appeared intermittently on seven separate nights between August 3 and August 29. Careful analysis revealed that the jets did not simply flicker on and off, but instead showed a clear precessional motion, a slow wobble repeating roughly every 7 hours and 45 minutes.Also Read | Massive interstellar object 3I/Atlas could be an alien craft, suggests Harvard astrophysicistFrom that motion, the team inferred something even more fundamental about the comet itself. The pattern suggests that the nucleus of 3I/ATLAS completes one full rotation roughly every 15 hours and 30 minutes, a significantly shorter spin period than earlier estimates had suggested. In practical terms, this means the comet’s icy core is rotating fast enough to periodically sweep active regions into and out of sunlight, producing the observed changes in the jets.After making its closest approach to Earth on December 19, when it came within about 168 million miles, or 270 million km, 3I/ATLAS began its long departure towards the outer solar system. Like Oumuamua and 2I/Borisov before it, the comet is expected to eventually escape the Sun’s gravitational grip entirely and disappear back into interstellar space.Yet even as it fades from view, its scientific legacy is becoming clearer. By revealing unexpected jet activity in a Sun-facing tail, 3I/ATLAS has offered researchers a rare glimpse into how matter behaves on a small, icy world forged around another star. The comet may soon be gone, but the clues it has left behind are likely to shape studies of interstellar visitors for years to come.