NASA's SPHEREx spots interstellar comet's outburst for 1st time
NASA's SPHEREx telescope just caught a rare outburst from comet 3I/ATLAS—an interstellar visitor discovered last July in Chile.
This makes it only the third known object to zoom into our solar system from another star.
SPHEREx spotted the comet bursting with water vapor, CO2
Using infrared, SPHEREx found the comet bursting with water vapor, carbon dioxide, methane, and even organic stuff—plus a small pear-shaped dust tail.
High CO2 hints that this icy traveler formed somewhere warm.
Scientists also noticed its ices are surprisingly fresh, kind of like local comets.
The comet was full-on erupting into space in December 2025
Turns out sunlight took its time reaching deep inside the comet's ice, so things didn't really erupt until December.
As Carey Lisse put it: "Comet 3I/ATLAS was full-on erupting into space in December 2025, after its close flyby of the sun, causing it to significantly brighten," and "Even water ice was quickly sublimating into gas in interplanetary space."
The telescope even mapped a huge cloud of CO2 stretching hundreds of thousands of kilometers.
Findings could help us understand how planets form
Studying 3I/ATLAS gives us a peek at what planets might be made of around other stars.
It's like getting clues about how worlds form far beyond our own solar system.