THE KARDASHEV SCALE. We have no idea what an alien civilization would look like. Humans are evolved primates. What if an alien species is reptilian? Or more like an insect? Or a hybrid of these? Or ...

Astrobiologists propose that alien civilizations need accessible coal deposits to industrialize exoplanets and become detectable from Earth.

After searching 100,000 galaxies for signs of highly advanced extraterrestrial life, a team of scientists using observations from NASA's WISE orbiting observatory has found no evidence of advanced ...

It's one of the biggest unanswered questions in science: if there's life beyond Earth, why hasn't it contacted us yet? Now, a scientist claims to have the answer – and it suggests aliens are more ...