Following the mantra, 'you won't find evidence of catastrophism unless you actively look for it' we had a prime example of this on BBC2 television last night, The Day the Dinosaurs Died. Scientist from the University of Bremen in Germany drilled into the Chcxulub crater off the coast of Yucatan and in so doing found ample evidence of an asteroid (or comet) striking the earth. Prior to them actively searching for evidence the asteroid theory was just that – a hypothesis that was repeatedly challenged. It actually showed a huge amount of sediment and rock fragments that had been laid down in the immediate aftermath. Previously, thick sediment layering that was dated by uniformitarian timescales, had been used to weaken the case for an asteroid strike. Now, will geologists come out of the closet and look at sediment layering on other occasions. Doubtful.
Alice Roberts then set about bringing in evidence of the dinosaur demise, visiting dinosaur beds in New Jersey, New Mexico, and Patagonia. She showed that the New Jersey area was affected by a huge tsunami wave that overtook the dinosaur herds in that location, but way down in Patagonia, she advanced the theory that as the dinosaurs there were too far away from the strike area they succumbed to starvation as a result of lack of food (the vegetation dying out as a result of so much dust and debris in the atmosphere shutting out warmth from the Sun). Alice was joined by the impressive Ben Garrod (onboard the ship doing the drilling and then visiting the university where the sea bed cores are stored). He seemed to ask all the right questions. The BBC, of course, like to do things their way, so in some sections it was a bit naff – but generally it came across well (although I found it irritating to repeatedly have the image of the asteroid hitting the earth) – but generally speaking, apart from the posturing in front of the camera, full kudos to the programme makers. Spot on.
It is going to be repeated on Wednesday evening at 11.00pm but you can also watch it on www.bbc.co.uk/iplayer/episode/b08r3xhf/the-day-the-dinosaurs-died …. and it is an hour long. The idea of a dust laden atmosphere, however long that lasted, is supported by the way even a volcano can spew debris into the atmosphere and cause an instant lowering of global temperatures – especially at the extremities. They came up with an impressive figure for the energy produced by the explosion, millions of times greater than Hiroshima (one billion times greater may have been a bit of an exaggeration but viewers got the message, it was awesome). They also explained why they had not actually encountered the remains of the asteroid (although they did not core into the centre of the crater but into a rim) as ninety per cent of it had been vapourised and deposited all around the world. I'm sure the Younger Dryas people can have a field day with that observation.