大象传媒

Could one of the best known and most glamorous scientific theories be wrong? Until recently most scientists thought they knew what killed off the dinosaurs. It was a 10 km-wide meteorite which smashed into Yucatan in Mexico. It caused world-wide forest fires, tsunamis several kilometres high, and an 'impact winter' - in which dust blocked out the sun for months or years. It was thought the dinosaurs were blasted, roasted, and frozen to death, in that order. But now there is increasing evidence the impact theory could be wrong. That suggestion has generated one of the bitterest scientific rows of recent times. Horizon sets out to sort the fact from the fiction.The impact theory was beautifully simple and hugely appealing. But a team of scientists led by Professor Gerta Keller of Princeton has uncovered a series of geological clues which suggests the truth may be far more complicated. She believes that the crater in the Yucatan is too old to have killed off the dinosaurs. That opinion sparked a massive row, as the supporters of the impact theory such as Prof Jan Smit of Amsterdam rubbished her ideas. But Keller's work is attracting increasing support. A range of scientists have begun to question other hypotheses connected with the impact theory. They say the evidence just does not support the belief that that wildfires raged all around the world, that dinosaurs perished amid acid rain as strong as battery acid, and that an 'impact winter' caused a massive and sustained drop in temperature. With stunning CGI graphics and the help of all the key scientists, Horizon explores the growing body of evidence which raises fundamental questions about the impact theory. It seems that the death of the dinosaurs may have been more complex than we had previously thought.