A NASA spacecraft has just reached its permanent observation point to begin a mission unlike any before. Known as IMAP, the Interstellar Mapping and Acceleration Probe will track invisible particles ...

On Friday (Dec. 19), the interstellar invader, comet 3I/ATLAS, made its closest approach to Earth, coming to within 168 million miles (270 million kilometers) of our planet at 1 a.m. EST (0600 GMT).

A mysterious comet from beyond our solar system is giving astronomers a rare glimpse into alien worlds — and it may have formed in a place far colder and stranger than anything around our Sun. The ...

New observations of the interstellar comet 3I/ATLAS include the first measurement of the abundance of deuterated water relative to ordinary water in an interstellar object. Astronomers using the ...