What Really Killed the Dinosaurs? (BBC Horizon).

Hmm, is this in the right place - I guess so ... so on we go:

I'm watching this as I post - so I don't know how it'll turn out, but it shows pretty good potential (translation for TV aside).

I've got an open mind on this as an extinction theory, so we'll see what this Horizon summary adds to the debate.

www.bbc.co.uk...

"Until recently most scientists thought they knew what killed off the dinosaurs. A 10km-wide meteorite had smashed into the Yucatan peninsula in Mexico, causing worldwide forest fires, tsunamis several kilometres high, and an 'impact winter' - in which dust blocked out the sun for months or years. It was thought that the dinosaurs were blasted, roasted and frozen to death, in that order.

[...]

But a group of scientists led by Prof Gerta Keller of Princeton and Prof Wolfgang Stinnesbeck of the University of Karlsruhe begged to differ. They uncovered a series of geological clues which suggests the truth may be far more complicated. In short, that the crater in the Yucatan is too old to have killed off the dinosaurs.

[...]

Therefore there must have been two impacts.

[...]

The Chicxulub impact, they said, was too old to have finished off the dinosaurs, and there must have been another impact somewhere else which was to blame. That crater has not yet been found."

and: www.bbc.co.uk...


[edit on 7-10-2004 by 0951]

If the asteroid hit the ocean then it wouldn't leave an impact crater. The Marianas Trench is 36,000 feet below sea level, I doubt a asteroid could go farther into the earth then that.

Originally posted by Murcielago
If the asteroid hit the ocean then it wouldn't leave an impact crater. The Marianas Trench is 36,000 feet below sea level, I doubt a asteroid could go farther into the earth then that.

That wouldn't be problem, reason why craters aro so shallow compared to diameter is that earths gravity is enough that crater deepness decreases lot when walls collapse to bottom of it.

There's much more logical reason, if crater is formed to and "edge" of ocean near subduction zone then it can disappear in time like twenty million years because oceanic plate goes under continental plate/to mantle.
That's why oldest crust in any bigger sea is just few hundred millions years old.

Dr Norman MacLeod of the Natural History Museum in London is among a large group of scientists who are convinced the dinosaurs were already being driven to extinction by climate change long before the arrival of the KT impact, or impacts.

Nice to say that, after all mankind has gotten itself to problems with nature in couple thousands years when dinosaurs ruled over hundred million years... and survived from couple changes.

Mass Extinction At The Triassic-Jurassic Boundary
And second one was when climate changed to dryer (causing decrease in vegetation) in the end of jurassic period leading to disappearing of big sauropods.

Hmm some useful additions to the debate for sure.

The show transcript is now online too, and ended with this quote: describing them as unlucky struck me as a touch ironic, although it couldn't really have been put any other way I guess as that's pretty much what it came down to in the end ...

"DAVID ARCHIBALD: Clearly dinosaurs were incredibly unlucky at the end of the Cretaceous to have all three things happen at the same time."

Sorry people, but the whole meteorit thing is just for kids. In other worlds meteorit killed the dinosaurs not. Remember that they were dying off slowly in THOUSANDS of years. If really the meteor impact was the cause, they would die off completely during few years, maybe decades.

It wasn't just the dinos...

About 80% of all life was extinguished in a geological second...a true ELE (extinction level event)...many of which have occurred in Earth's past. (about every 80 million years of so, if I recall right, so we've still got a few million years till the next one, hehe....)

The meteorite was one fell blow, but the fallout (killing off of basic components of the food change) is what continued to kill off the dinos, and other life that couldn't adapt well to the changes. A second impact is plausible, but I'm not so sure it's even necessary, to explain it...

I read in a book Not By Fire but by Ice by Robert W. Felix that oil drillers in the Gulf had hit volcanic rock in the area that the meteor was supposed to have hit leading to the idea that what really happened there was the explosion of a massive underwater volcano. What would happen if a Yellowstone size event were to happen in the water? Would this heat the water to the extent that the increased evaporation would block out the sun for a great period of time resulting in an ice age and the deaths of the dinosaurs?

Originally posted by Indy
I read in a book Not By Fire but by Ice by Robert W. Felix that oil drillers in the Gulf had hit volcanic rock in the area that the meteor was supposed to have hit leading to the idea that what really happened there was the explosion of a massive underwater volcano. What would happen if a Yellowstone size event were to happen in the water? Would this heat the water to the extent that the increased evaporation would block out the sun for a great period of time resulting in an ice age and the deaths of the dinosaurs?

Probably not. We do have massive volcanos in the ocean, and what happens is that the lava cools quickly as it hits the water. Mountains form, and eventually you get something like Mauna Loa in Hawaii.

The Urantia Book offers a view of the dinosaurs extincton some may find interesting. It isn't very spectacular, but interesting none-the-less.

mercy.urantia.org...

[edit on 04/10/10 by GradyPhilpott]

maybe the extinction was cause by the number of bacteria's at that time and maybe cause the dinosaurs to become sick and eventualy die....btw...if a meteorite did hit the earth....wouldn't the water......like 'spill out' ?....and also if the impact is so big....wouldn't it cause everything to go to the other end.......and this would cause the countries to hit each other....?

Originally posted by Indy
I read in a book Not By Fire but by Ice ?

Fire and Ice

Some say the world will end in fire,
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.

-- Robert Frost

Originally posted by Indy
...that oil drillers in the Gulf had hit volcanic rock in the area that the meteor was supposed to have hit...
Would this heat the water to the extent that the increased evaporation would block out the sun for a great period of time resulting in an ice age and the deaths of the dinosaurs?

No wonder if there's some rock with signs of melting, cosmic impacts melt huge amounts of bedrock.

Wrong, massive increase in amounts of water vapour in atmosphere would cause greenhouse effect.
(its entirely other question to where that extreme greenhouse effect leads)


www.lpl.arizona.edu...

Originally posted by Gazrok
It wasn't just the dinos...

About 80% of all life was extinguished in a geological second...a true ELE (extinction level event)...many of which have occurred in Earth's past. .

besides, todays' crocodile-alligator lineage has fossils from the age of dinosaurs. And lotsa smaller and tiny warm blooded mammals survived the 'conditions' which destroyed the other 99.9% of the dinosaur genus.
So the meteorite, asteroid isn't the sole/final/complete answer!...but

Investigations by BBC,Nature and other s in Britan ....along with Discovery,National Geographic and others' in USA...should keep the ball rolling...
>?? the pattern of global extinctions, recurring with a cosmic regularity ??<

Novas, Gamma ray bursts are some GOOGLE up searches to explore

reply to post by Axl


what if the countries split apart. the scientist says bfore there was only 1 continent and due to many reasons it split apart.the meteorite can be one of the reason for the split. with the split the meteorite killed the dinosours too. if bacteria killed the dinosours why does the fossils dont show anything about bacteria attack.

A few very right wing thinkers say that the Dinosaurs where in fact an itelligent race of animal (not as we know animals to be).
They had a very intelligent brain that allowed them to think and create as we do.

Potentially this lead to nuclear war 65 million years ago - hence all extinct. They then left Earth and migrated to the Plaedes and we know them as Reptillians.

Think this is to way out there :-) maybe not

Valorian

[edit on 29-7-2008 by Valorian]

Originally posted by GradyPhilpott
The Urantia Book offers a view of the dinosaurs extincton some may find interesting. It isn't very spectacular, but interesting none-the-less.

mercy.urantia.org...

[edit on 04/10/10 by GradyPhilpott]

....BINGO.... :-)