In the spirit of the season, the interstellar comet 3I/ATLAS is changing color as it leaves the sun behind — shifting from a reddish tint to a faint green glow. That visible change signals the comet is reacting to solar heat and releasing new gases in space, giving scientists fresh clues about what it is made of and how it behaves.

Two bright green comets are streaming through the skies and are visible to skygazers in the Northern Hemisphere. Both hail from the outer edges of our solar system — possibly what's known as the Oort Cloud, well beyond Pluto. Comet Lemmon will have its ...

The Southwest Research Institute-led Ultraviolet Spectrograph (UVS) aboard NASA's Europa Clipper spacecraft has made valuable observations of the interstellar comet 3I/ATLAS, which in July became the third officially recognized interstellar object to cross into our solar system.

We are in Germany and it's winter, so we can confidently assume that it is cold, with possible snow covering the fields and roofs of houses. Here we meet the protagonist of this story, farmer and astronomer Johann Georg Palitzsch.