Add Yahoo as a preferred source to see more of our stories on Google. The fossilized tail bones of an Ichthyosaurus, around 190 million years old and weighing 800 kilograms. - Markus Scholz/picture ...

The Silurian Hypothesis asks whether signs of truly ancient past civilizations would even be recognisable today.

The idea that an advanced civilization existed on Earth long before humans is fascinating, but scientists aren't convinced. Experts have explored this possibility by asking what traces a technological ...

Earthlings, brace yourselves: the galaxy may be emptier than your last Tinder date. According to a new study, any alien civilizations out there? Probably short-lived — and doomed to fail spectacularly ...

(CNN) — When astrobiologist Adam Frank walked into the office of NASA scientist Gavin Schmidt, he had what he believed was the weirdest question: do aliens experience climate change? It took just ...