New evidence shows that, far beyond Pluto, there may exist a hypothetical planet referred to as Planet X or Planet Nine.

The comet is the third object ever confirmed to have entered our cosmic neighborhood from elsewhere in the galaxy. Space ...

Before 3I/ATLAS, the only other confirmed interstellar tourists we've seen were the now-famous, cigar-shaped 'Oumuamua' in ...

A cosmic monster shows up in our backyard and suddenly physics starts acting like it drank five espressos. Let’s explore how ...

I/ATLAS comet is the 3rd-ever object discovered that originated from outside our solar system. It's not a threat, approaches ...

Interstellar comet 3I/ATLAS is now visible in the UK night sky! The third confirmed alien visitor, whose chemical fingerprint is 'older than our Sun', makes its unrepeatable, 221,000 km/h flyby. Get ...

In a new study published in The Astrophysical Journal, a group of researchers from the University of Colorado Boulder ...

This is the strongest evidence yet of a rocky planet beyond our solar system with an atmosphere. Astronomers using the James ...

The interstellar comet 3I/ATLAS reaches its closest point to Earth on Dec. 19, allowing close study with no threat to the ...

Astronomers have followed 3I/ATLAS since its discovery on July 1. Hubble photographed it on July 21 from 277 million miles ...

New 3I/ATLAS images from NASA and the ESA suggest the interstellar comet is active as it approaches Earth in December.

Images captured by NASA's Parker Solar Probe as the spacecraft made its record-breaking closest approach to the sun in ...