NASA's SPHEREx telescope spots comet 3I/ATLAS shining brightly
Technology
NASA's SPHEREx telescope just spotted comet 3I/ATLAS suddenly getting brighter in December 2025, a couple of months after it swung closest to the Sun.
This rare visitor from another star system showed off a huge cloud of carbon dioxide, water ice turning straight into gas, and a chunky dust tail made of grains too heavy for sunlight to push away.
Comet's journey through the solar system
First discovered in July 2025 by astronomers in Chile, comet 3I/ATLAS zipped past Mars in October and may cross Jupiter's path later.
For a while last fall, it was visible through September before moving too close to the Sun to observe, reappearing on the other side of the Sun by early December.