At nearly twice Earth's size with a denser atmosphere, this fictional world hosts creatures that dwarf anything alive today, ...

Are we alone in the universe? Consider mysterious "extraterrestrial" radio signals. Unexplained gases on other planets.

Steven Spielberg's claims that aliens have already visited Earth have drawn a mixed but pointed scientists' reaction this week, with astrophysicists in the UK and Australia stressing that while ...

Eventually, we'll launch a mission dedicated solely to studying an interstellar object. When that day comes, which one should ...

Explaining the passage of time has been a gnarly problem in physics basically forever, but physicist and computer scientist ...

Astronomers have recently started looking for black holes bigger than galaxies. Brian Lacki explains how these “stupendously ...

We look at shootings by federal immigration agents.

Professor Carol Oliver suggests that time dilation, a cosmic phenomenon, may deter aliens from visiting Earth, as ...

This new group, which is led by Harvard professor Avi Loeb, aims to advise the Trump administration and the U.S. intelligence ...

A Soviet astronomer in the 1960s proposed a scale to classify hypothetical alien civilizations. Here’s why the framework is ...

Last year, an interstellar traveler entered our solar system. Some speculated that it was an alien spacecraft, but it turned ...