成人论坛

Presenter Gareth Mitchell and guest Professor John Knapton, clearly stunned by recent events, talk about how the fire from the aircraft impacts caused the Twin Towers of the New York World Trade Center to collapse, causing devastating loss of life [9/11].

Also on the programme: Evidence that genetically-modified crops can have real impact on natural eco-systems. An atlas of the world's coral reefs shows only half the previously estimated reef area, and much of that is degraded. A black hole discovered moving through our galaxy. Ancient jaw bone which may tell us when we learnt to care.