Life on Mars? Quantum Gravity. The deep origins of bird song

Mars is about to be visited by the first space mission for 40 years which is designed to seek signs of life on the Red Planet. Adam Rutherford talks to Dr Manish Patel of the Open University, a senior scientist on the European Space Agency's ExoMars Trace Gas Orbiter. Once the spacecraft starts work, it may solve the mystery of ebbs and flows of methane gas in the Martian atmosphere. It may answer whether the gas is being produced by life beneath the planet's cold dusty surface.

The American space agency Nasa already has a mission well underway on the Martian surface.. For four years, Curiosity has been exploring the deep geological past of a huge Martian crater and mountain. Recently possible signs of liquid water have been seen nearby. But rather than going closer to study it, Nasa wants the rover to avoid it. Project scientist Ashwin Vasavada explains why.

Carlo Rovelli is a theoretical physicist and writer. His latest book 'Reality is not what it Seems' explores the history of thought about the physical nature of the universe and one of the latest incarnations of that great quests - loop quantum gravity theory. He talks to Adam about the fine grain of space and time, and exploding black holes.

Palaeontologist Julia Clarke has discovered the oldest fossil of a bird's organ of song, the syrinx. At the University of Texas, Austin the delicate structure turned up in an X ray scan of a 66 million year old bird fossil from Antarctica. The fossil syrinx is so well preserved, it is possible to say what the call of this ancient bird Vegavis would have sounded like. It's also a massive boost in the quest to discover when birds first sang and recreating the dawn chorus back in the Age of Dinosaurs.