In this edition of The Naked Scientists: Evidence of a carbon cycle on Mars has been unearthed by the Curiosity rover. What does it mean for the red planet’s past habitability? Also, the cannabis-based painkiller as powerful as an opioid, but without the side…

The team behind the Curiosity Rover, which is trundling around a site called Gale Crater and using a range of instruments to analyse surface samples, have announced the detection of significant depos…