New infrared observations reveal that the rare interstellar visitor comet 3I/ATLAS has brightened dramatically during its farewell tour of the solar system.
NASA’s Sphereex (Spectrophotometer for the History of the Universe, Era of Reionization, and Ice Explorers) A space telescope captured the sight of a comet emitting a surge of gas, dust, and complex molecules in December 2025, two months after the object’s closest approach. solar — an astonishing explosion giving scientists the clearest chemical picture yet of material forming around another star. statement From NASA.
”Comet 3I/Atlas “After its close approach to the Sun, it really ejected into space in December 2025, becoming noticeably brighter. Even water ice was quickly sublimating into gas in interplanetary space,” Carrie Risse, lead author of the study, said in a statement.
Discovered by the ATLAS asteroid probe in July 2025, 3I/ATLAS is the third confirmed interstellar object ever to transit our solar system. 1I/Oumuamua 2017 and 2I/Borisov However, unlike its predecessor, 3I/ATLAS hosted an extended chemistry show that SPHEREx was uniquely equipped to observe.
SPHEREx studies the universe in infrared light, allowing scientists to identify not just the dust but also the detailed mixture of molecules that stream out. comet – Contains substances that serve as important components of planet formation, such as water, ice, carbon dioxide, methane, methanol, and cyanide.
Comets are usually most active nearby, but perihelionAs solar heat evaporates surface ice, SPHEREx data show that 3I/ATLAS strengthened long after that point. This suggests that sunlight slowly penetrated beneath the comet’s surface, delaying the subsequent release of buried ancient ice, the statement said.
“Comets are made up of about one-third of their volume as water ice, so this released a large amount of new carbon-rich material that was trapped in subsurface ice,” Risse said in a statement. “We are now seeing early normal ranges. solar system Materials typically ejected from comets, such as organic molecules, soot, and rock dust. ”
Because 3I/ATLAS originated outside our solar system, its chemistry provides a rare opportunity to compare icy objects that have formed around our local comet and other comets. star. The similarities and differences could help scientists determine whether planets and the raw materials for potential life are common across the Milky Way.
“The comet likely spent many years traversing interstellar space, exposed to high-energy cosmic rays, forming a crust that was processed by that radiation,” study co-author Phil Korngut said in a statement. “But now that the sun’s energy has had time to penetrate deep into the comet, the primordial ice beneath the surface is warming and erupting, releasing a cocktail of chemicals that haven’t been exposed to space for billions of years.”
Their discovery is Published February 2026 Published in the AAS journal Research Notes.