More Evidence Supports Massive Asteroid Strike

InnerPeace Volunteers writes "From a BBC Sci/Tech article: The idea is that a giant asteroid about 10 kilometres wide, travelling at 90,000 km/hour slammed into the Earth at the southern margin of North America. This was a case of global devastation rather than North American catastrophe. The asteroid devastated pretty much everything."

Re:gulf of mexico

[jc42]

Well, yeah; probably lots of people would guess at such a hypothesis. But it's not consistent with what is known about the 65-Million-year-old crater on the coast of Yucutan. You'd expect the crater to be near the middle of the Gulf, but it's not. And the crater itself is only maybe 1/10 the diameter f the Gulf.

Also, any geologist will probably tell you that the Gulf of Mexico is much older than that. It's really a very old feature of that part of the planet.

But this shouldn't be taken as a criticism of the idea. The scientific process isn't harmed by such wild guesses. They are often the start of interesting findings. The Gulf of Mexico does look like a "circular feature". It could be an impact crater. But apparently it isn't.

For that matter, the Pacific Ocian is also roughly circular. There has been lots of hypothesizing about this, including the idea that it's the scar left from when the moon was torn from the Earth by the impact of another planet. The scientific jury is still out on this one. After 4.5 billion years, there's not a whole lot of fossil evidence left ...

"Suddenly disappeared..."

[Philippe]

I want to point out that the dinosaurs did not disappear "suddenly", 65MY ago. The decline of dinosaurs began millions of years before that fateful iridium trace in the geological record (aka the cretaceous-tertiary or K-T boundary), and dinosaurs were found in the fossil record on top of that boundary. It's not like they disappeared in one, ten or a hundred years. It took millions of years (tens of thousands of generations) for the dinosaurs to disappear.

Philippe

This is akin to the "Cambrian explosion" theory where at the beginning of the Cambrian, there was suddenly (here's that word again) "exponential" increase in diversity of form (see the Burgess shale for an example). But if you look at it in linear time, and not in compressed (geological) time, the exponential curve looks more and more linear. An explosion that takes hundreds of millions of years to occur is not really an explosion, wouldn't you say?

Re:Everything but the frogs

[Anonymous Coward]

You are making a basic false assumption that the current variety of amphibians present today are the same as those before 65 million year ago. If a particular species exists today and could not have survived even a minor environmental change (much less the global fallout winter following a large meteor strike), then that ONLY means any similar species would not have survived the meteor strike* at the end of the Cretaceous Period.

*The evidence for this is more than compelling to me (more available through http://search.npr.org/cf/cmn/cmnpd01fm.cfm?PrgDate =11%2F23%2F2001&PrgID=3 [remove any spaces] and look for 'Dinosaur Deaths.' Note that this is based on a Science magazine article). If you choose to ignore or discount the same (which is too numerous and requires too much background to summarize), sorry.