A recently-observed interstellar comet, 3I/ATLAS, released molecules containing the building blocks of life as it passed close to Earth in December 2025, according to new data from NASA’s SPHEREx space telescope. The discovery offers a rare opportunity for scientists to study the fundamental components of life originating from beyond our solar system.
SPHEREx observed the comet as it approached the Sun, reaching its closest point to Earth at approximately 270 million kilometers. The telescope detected organic molecules including methanol, hydrogen cyanide, and methane – compounds crucial to biological processes on Earth, though they can also form through non-biological means.
“3I/ATLAS exploded into space after approaching the Sun, releasing carbon-rich material previously locked in ice beneath its surface,” explained Carey Lisse, an astronomer at the Johns Hopkins Applied Physics Laboratory. The comet is composed of roughly one-third water ice, and as this ice vaporizes, it disperses dust, soot, and organic molecules into space.
While organic molecules are commonly found in comets, the findings from 3I/ATLAS are significant because they support the theory that comets may distribute the “seeds of life” to other planets, including Earth. Each visit from an interstellar comet, represents a natural cosmic laboratory for scientists.
First detected in July 2025, 3I/ATLAS travels at approximately 221,000 kilometers per hour in an orbit around Jupiter. Researchers estimate the comet has traversed interstellar space for billions of years, gaining gravitational boosts from stars and nebulae before entering our solar system.
Launched in March 2025, SPHEREx utilizes 102 infrared sensors to scan the entire night sky. The telescope captured data on the comet between December 8th and 15th, a fortunate occurrence given the rarity of interstellar comet visits and the fact that such an event was not initially scheduled for the mission.
“In this case, a galaxy sent us a piece of a distant star system just months after launch, and SPHEREx was ready to observe it,” said Yoonsoo Bach of the Korea Astronomy and Space Science Institute.
Currently, 3I/ATLAS is approaching Jupiter, where NASA’s Juno spacecraft will have a final opportunity to study the comet before it leaves our solar system permanently. This discovery marks a key milestone in the study of interstellar comets and the search for the building blocks of life in the universe.