A rare comet from another star system is revealing just how different alien solar systems may be from our own.

Measurements of this interstellar comet’s molecular makeup show an excess of heavy water molecules that is dramatically different from anything known to have ever formed around our sun ...

The presence of deuterium, an isotope of hydrogen, in 3I/ATLAS suggests the interstellar comet formed in a much colder place ...

Learn more about the interstellar traveler, Comet 3I/ATLAS, and what researchers know about its place of origin.

Objects such as 'Oumuamua, Borisov and recently 3I/ATLAS have opened our eyes to the reality that outsiders regularly visit our solar system — and we're about to start spotting a whole lot more of ...

Illustration comparing the planets of the Solar System and the Sun on the same scale. The planets are shown to scale relative to each other but their distances are not. From left to right the bodies ...