Science has a lot to say about life and death. Doctors can carry out an autopsy before the deceased starts to decompose, to establish the cause of death. Forensic scientists collect evidence after a homicide. Does being dead mean that your heart stops beating or your brain stops being conscious? Your body is just a machine to carry your brain around, but if you are in a coma you can be pronounced 'brain dead', even though your heart and lungs keep working, a bit like a zombie. And when you die, what about the afterlife..?