British TV astronomer Mark Thompson has just announced that he is going to try to break the world record for the longest lecture. If he's to succeed, Thomspon must talk for 140 hours, or more than five and a half days. Extreme sleep deprivation can be dangerous but Mark says he has all the medical controls in place to remove the risk as he attempts to smash the record on September 11 this year at the University of East Anglia. For such a marathon lecture, Thompson has chosen a big subject: space. "It's going to be the ultimate space lecture," Thompson promises.