Since I wrote about this 65-million-year-old impact, scientists have agreed that it did end the Cretaceous Period. Or more dramatically the entire Mesozoic Era – the time of the dinosaurs – for the planet’s fifth major extinction event. I shall have more to say about the sixth extinction but I still wonder what this impact looked like.
In my previous post, I imagined taking a Redditch-size ice-cream scoop out of the planet, preferably Redditch itself, to be the meteorite. It turns out to have been more the size of Bristol, which is a fine coincidence with me having moved from the former to the latter. I also posited firing it out of a great big supersonic gun, but this time I want to make the target on a continental shelf, just as Chicxulub was.
I’ve chosen somewhere near Lundy. You’ll see why.
On a planetary scale, hurling Bristol into the sea is pretty small beer – just a pinprick on the globe – but if you’re anywhere near it… how near? Most of us have felt that satisfactory thump of something quite big going off, like a huge firework. Imagine a house going off then, or a plane (I’m sure we can all do this), or an office block, then a complete city. You’d get out of the immediate neighbourhood.
So now, how far? The Chicxulub impact threw up instant Himalayas ninety miles away. That’s Bristol distance from Lundy. That’s Weymouth too. And Aberystwyth. Actually, that’s the entire south-west of England and South Wales done for; and it doesn’t end there.
A superheated blast of air racing away from the crater would incinerate anything inflammable (including humans) for miles around. I don’t know whether this would stretch to London and the Midlands but the biggest earthquakes in human history would level those cities, probably the rest of England, most of Ireland and a good chunk of northern France.
So much for the immediate effects. What about the ensuing tsunami? Oh yes, that comes as a free gift with a coastal impact. Look at the height of this wave though – half a mile to a mile. The recent ones in Samoa, and more distantly Indonesia, didn’t even crawl out of the cradle in comparison. This is a wave quite capable of crossing the Atlantic and hitting the USA and the Caribbean, not just with a few feet of water but a few hundred.
The Americas would have about ten hours warning. I doubt that’s long enough to mobilise millions of people to higher ground. In any case, they would most likely find there an incandescent rain of dust and rock, again igniting anything inflammable.
It doesn’t quite play out like the disaster movies I’ve seen, largely because there’s little hope of survival within a few hundred miles and slim pickings within a few thousand. Get out of that, Bruce Willis and John Cusack.