The Naked Scientist team present the latest science news, analysis and breakthroughs.

This week: scientists think they've revealed what makes ketamine an effective antidepressant, the astonishing navigational capabilities of bees, and a brief guide to aliens with astronomer Adam Frank.

And Titans of Science continues with the renowned astrophysicist discoverer of the accelerating expansion of the universe and the man who gave us dark energy, Brian Schmidt.