Just before this BBC podcast gets underway, here's something you may not know.

My name's Linda Davies and I Commission Podcasts for BBC Sounds.

As you'd expect, at the BBC we make podcasts of the very highest quality featuring the most knowledgeable experts and genuinely engaging voices.

What you may not know is that the BBC makes podcasts about all kinds of things like pop stars,

poltergeist, cricket, and conspiracy theories and that's just a few examples.

If you'd like to discover something a little bit unexpected, find your next podcast over at BBC Sounds.

Thanks for downloading the In Our Time Podcast.

For more details about In Our Time and for our terms of use, please go to BBC.co. UK forward slash radio for

I hope you enjoy the program. Hello the hunt for extraterrestrial life is no longer

confined to the pages of science fiction but occupies astronomers,

geologists, mathematicians, and new schools of scientists, astrobiologists and xenobiolists.

New planets have been observed far beyond our solar system, and telescopes are being built that will enable us to look for water and oxygen on these distant planets.

If water and oxygen are present, there's every reason to suppose that some form of life might also exist there.

It's even been suggested that we might find life within our own solar system.

One of Jupiter's moons Europa appears to be covered in an ice-crusted ocean,

and there's evidence that water once flowed on Mars.

And on our own planet, we've found forms of life, extremophiles, that don't need the sun,

living in set on energy from volcanic vents on the ocean floor.

This discovery has changed our concept of what life needs in order to survive.

Could life only exist on another planet like ours and what are the chances of ever discovering such a planet?

If we find life will it be intelligent, or a simple bacteria like entity?

And if super intelligent aliens exist, why aren't they here? With me to discuss the possibility of extraterrestrial life

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