Are we alone? New discovery raises hopes of finding alien life

Tentative evidence for life on a distant world is exciting, but unconfirmed. As new telescopes bring exoplanets into sharper focus, is the truth out there?

Towards the end of his life, the cosmologist Stephen Hawking was asked about the odds of finding intelligent alien life in the next two decades. The probability is low," he declared in 2016, and took a lengthy pause before adding: Probably."

This week, other scientists from the University of Cambridge reported tentative evidence for two compounds in the atmosphere of a planet, K2-18b, that sits in the constellation of Leo 124 light years away.