Bbc Inside Science

The European Space Agency's satellite Mars Express has identified what we think is a subterranean lake of liquid near the south pole of the red planet. The question of water on Mars has been around for years, and we've known about water ice, and there's been the possibility of seasonal flowing water on Mars for a while. But if this result is right, this is the first case of a substantial stable body of liquid water on Mars. Adam Rutherford talks to Roberto Orosei of the Radio Astronomy Institute in Bologna whose team made the discovery. Where should scientists be directing their efforts next in the light of this new finding? We hear from NASA's Chief Scientist Jim Green. We've been growing embryonic cells in petri dishes for a few years now, to try to fill in the gaps in our understanding of early development, but the tissue that grows never really resembles an actual embryo. Magdalena Zernicka Goetz is a developmental biologist from Cambridge University and in a paper out this week has leapt over this hurdl