Are we alone in the universe?

Scientists have long referred to the Goldilocks zone – the region around a star where conditions are not too hot and not too cold but “just right” for life. Joined by a live audience at the Cheltenham Science Festival in the UK, Tom Whipple asks what are the true limitations of alien life? How do we spot it? And have we been looking too narrowly? Planetary scientist at MIT Sara Seagar discusses…