End of the "Lone Asteroid" Theory?

Keller's Conclusions Strongly Refuted by Punchinello · 2004-03-02 04:56 · Score: 5, Interesting

Gerta Keller's conclusions are being strongly refuted by Jan Smits, one of the researchers that got funding for the core samples used in the study. He said in this NPR clip that he is really upset that Keller's research passed peer review without catching the obvious mistakes.

--

Remember... ZG9uJ3QgZm9yZ2V0IHRvIGRyaW5rIHlvdXIgb3ZhbHRpbmU=

Re:Keller's Conclusions Strongly Refuted by MuParadigm · 2004-03-02 05:25 · Score: 4, Insightful

This is *one* study as opposed to many studies tending to confirm the theory. I doubt it's conclusive.

This isn't to say that it's wrong, but I think it's obvious that Keller's paper certainly shouldn't be accepted as definitive unless and until studies confirming it are undertaken and reported.
Re:Keller's Conclusions Strongly Refuted by anantherous+coward · 2004-03-02 05:54 · Score: 5, Insightful

The significance of publication in a peer reviewed journal should not be overestimated as the press seems to do so often.

I remember from about 10 years ago that an article on letter on equidistant letter spacing in the Bible (I.e. Bible Codes) was published in "Statistical Science" -- a recongized peer reviewed journal. I also recall that those who approved the article did not agree with it. The reason for publishing it was because they could not refute the mathematics in it. It was a sufficiently interesting finding and methods to merit publication. The work was later effectively refuted, as most knew it would be -- the hypothesis was nutty.

The point here is that Keller's work may have merited publication even if we regard it likely that he is wrong. I don't know one way or the other myself. I guess I am reacting a little bit to the idea that Smits is upset that Keller was even published. It smells of censorship. But maybe he is right.

Less Violent End? by ackthpt · 2004-03-02 04:56 · Score: 5, Interesting

I caught this story on the BBC World News, Monday morning, along with the theories of the extinction of Aristide's presidency.

Back when I took astronomy the standard theories were carted out before us for our own inspection and consideration.

I've not been convinced climatic change did them in as most theories seemed predisposed to a direct impact on the dinosaurse themselves. i.e. the earth passed through the tail of a comet and the atmosphere cooled and they died off. I'm more inclined to some environmental change which impacted the low end of the food chain, plants in particular, but it still doesn't explain why aquatic dinos went, too.

I'm looking for a theory that says the earth was a warmer place with most of that fossil fuel carbon still on the surface (where we're presently putting it again, one study observed plants are taking up the extra carbondioxide in the air, what's the long term impact of that?) As the carbon became buried (ever think about how much green stuff it took to make pertroleum deposits or coal seams?) the food changed and those at the bottom of the chain adapted or perished. Perhaps dinosaurs were really hugely inefficient creatures and require large amounts of energy, whereas mammals and birds are quite efficient.

Anyway, that's my two cents. Anyone who can point me toward some theories which follow that logic, as opposed to the big-exciting-asteroid-or-comet theories much appreciated. I think in extinction theories, the ones involving some violent cataclysm get too much press, probably due to the sensational value.

--

A feeling of having made the same mistake before: Deja Foobar

Re:Less Violent End? by Anonymous Coward · 2004-03-02 05:09 · Score: 5, Interesting

Actually, "fossil fuels" did not come from plants or dinosaurs.... Nitrifying bacteria consumes rock and the byproduct is tar, oil etc. The bacteria uses the carbon in the soil/atmosphere to facilitate the reaction.
I can't believe they still teach that oil came from Dinos in our schools...
Re:Less Violent End? by mc6809e · 2004-03-02 05:13 · Score: 4, Interesting

I'm looking for a theory that says the earth was a warmer place with most of that fossil fuel carbon still on the surface (where we're presently putting it again, one study observed plants are taking up the extra carbondioxide in the air, what's the long term impact of that?) As the carbon became buried (ever think about how much green stuff it took to make pertroleum deposits or coal seams?) the food changed and those at the bottom of the chain adapted or perished.

So you're saying that, basically, as carbon was drawn out of the atmosphere and put into what are now coal seams and oil fields, plant productivity was reduced. This reduction made food less available for dinosaurs and so they perished. Interesting theory.

There have been studies showing that many plants are CO2 limited. When CO2 is increased, plant biomass increases greatly. Conversely, the less CO2 available, the less productive the plants are.

Seems to be compatible with your theory.
Re:Less Violent End? by ackthpt · 2004-03-02 05:19 · Score: 5, Interesting

Actually, "fossil fuels" did not come from plants or dinosaurs.... Nitrifying bacteria consumes rock and the byproduct is tar, oil etc. The bacteria uses the carbon in the soil/atmosphere to facilitate the reaction. I can't believe they still teach that oil came from Dinos in our schools...
Not dinos, but plant matter, the most prominent example of this process ongoing today are peat-bogs. North of where I lived in Michigan were muskegs, effectively small lakes which eventually filled in with mosses. Assmume this process continues for some time, building up a dense layer of dead moss at the bottom, as new moss continues to grow on top, then a glacier (like the ice age) deposits a cap of sand/gravel/clay on top of it and over successive millenia that layer continues to be overlayed by sediments, etc. Examination of coal often reveals the plant matter it was made from. Consider a 1 meter thick coal seam and the kind of pressure upon it, what was the original dept of this accumulation of plant matter?

--

A feeling of having made the same mistake before: Deja Foobar
Re:Less Violent End? by Illserve · 2004-03-02 05:25 · Score: 5, Interesting

Mammals aren't particularly efficient. In fact it's damned expensive to keep our homeostatic mechanisms in place.

It's worth it of course, active temperature regulation lets us stay awake during the night and has let our neurons become more delicately tuned (and therefore we're smarter than cold blooded critters).

But it's a mistake to assume that we're more efficient from an energy perspective. You spend a huge chunk of you caloric input keeping your extremeties warm, and your brain cool. It's like your own personal environment suit built into your body. Lots of advantages, but very expensive to operate.

Now maybe their extreme size made dinosaurs less efficient, but I tend to think it's that being cold blooded they are less resistant to climactic change. A period of dynamic weather, with patterns changing faster than migration could handle, would tend to be very bad for anything cold blooded.

Also consider, before warm blooded things came about, nighttime must have been very safe and quiet in large areas of the world. All of a sudden warm blooded critters arrive on the scene and find this amazing niche, namely eating sleeping dinosaurs at night :)
Re:Less Violent End? by cens0r · 2004-03-02 05:30 · Score: 5, Interesting

I thought there was a lot of debate about whether or not dinosaurs were cold blooded? Most recent studies I've seen show that many of the dinosaurs had feathers, and most likely were closer to ostriches than reptiles. This means they were just as likely to be warm blooded as cold blooded.

--
Jack Valenti and Orrin Hatch will be first up against the wall when the revolution comes.
Re:Less Violent End? by ackthpt · 2004-03-02 05:31 · Score: 4, Interesting

There have been studies showing that many plants are CO2 limited. When CO2 is increased, plant biomass increases greatly. Conversely, the less CO2 available, the less productive the plants are.
Which, on first look, would seem to cover the extinction of aquatic dinos, too. As their food became less plentiful. Those which adapted to the changing food chain survived. That there were some very large carnivores suggests to me that they prospered on a readily available supply of food.

--

A feeling of having made the same mistake before: Deja Foobar
Re:Less Violent End? by ackthpt · 2004-03-02 05:52 · Score: 5, Interesting

I thought there was a lot of debate about whether or not dinosaurs were cold blooded? Most recent studies I've seen show that many of the dinosaurs had feathers, and most likely were closer to ostriches than reptiles. This means they were just as likely to be warm blooded as cold blooded.
Based upon observation of like present day creatues I'm inclined to these argements:
Dinos were cold blooded and lived in a hothouse climate.
Dinos were warm blooded and required high caloric intake.
That some were found to nest suggests more than simply protecting the eggs, they were keeping them warm. These were not buried nests, but on the surface, exposed. How would a cold blooded animal keep an egg warm?

--

A feeling of having made the same mistake before: Deja Foobar

Ah, memories.. by grub · 2004-03-02 04:56 · Score: 5, Funny

This brings back memories.

I remember having a beer at my buddy Vijay's place in India (he was an outsourced Fern & Brush Maintainer for the Pangea Shrubbery Co. in the Late Cretaceous) Anyhow, I was working on my tan as the sun's light had only recently begun shining through to the Earth's surface thanks to the Chicxulub hit years before.

Vijay had just finished telling me a great joke about his dog having no nose when we saw a massive asteroid coming down. Vijay just muttered "Oh bugger, not again." The sad part of the whole thing was that I had tanned lying on my stomach that morning. My face and frontside were ghostly white for ages.

I was a laughing stock for most of the Tertiary period..

--
Trolling is a art,

Re:Ah, memories.. by Anonymous Coward · 2004-03-02 05:09 · Score: 4, Funny

got you beat, when I was a microbe on mars we were having a ball of a time with our family when an asteroid hit. It sent half of our civilization into space, most died. But some got trapped in rocks and landed on that "earth" planet. Then they mutated into hideous monkey beings that are so arrogant most think they are the only life in the universe and that there is a master creator being called God - who is also shaped like a hideous monkey being. And now some of the hideous monkey beings have started morphing into these vicous "trolls" who make stupid jokes.

Days before life on earth, THOSE were the days.

Only if... by FortKnox · 2004-03-02 04:57 · Score: 4, Funny

If only Bruce Willis had lived back then...

--
Good quote, too many chars. Seriously, the slashdot 120 char limit sucks!

Re:Only if... by ackthpt · 2004-03-02 06:06 · Score: 4, Funny

If only Bruce Willis had lived back then...
Well, you know Shirley MacLaine did. You should ask her what happened.

--

A feeling of having made the same mistake before: Deja Foobar

hmmm by potaz · 2004-03-02 04:58 · Score: 5, Funny

"from the this-changes-everything-and-nobody-cares dept."

I'm thinking maybe the dinosaurs involved cared just a little...

--
dinosaur comics

Obviously... by JackHart · 2004-03-02 04:59 · Score: 5, Funny

Obviously it was the second asteroid on the grassy knoll!

This was on NPR yesterday and they said . . . by JustAnotherReader · 2004-03-02 04:59 · Score: 5, Interesting

This was on NPR yesterday and they said that there were some pretty serious flaws in the theory. One scientist went so far as to say "I don't know how this got through peer review. It should never have been published"

It may just be scientist ruffling their feathers at a new theory, or there may very well be serious problems with the evidence. It's certainly not a final answer yet.

Back the truck up... by djupedal · 2004-03-02 05:00 · Score: 4, Insightful

The second impact may have been in the Indian Ocean

I'm checking my notes now, but as I recall, the 'Indian Ocean' wasn't there when the second one augered in. Who writes this stuff....

Re:Religious fanatics, unite! The end is very nigh by Anonymous Coward · 2004-03-02 05:01 · Score: 5, Funny

Dont be a fool. Religious fanatics dont believe in dinosaurs.. first of all, to them earth is only 10,000 years old, second, dinos arent mentioned in the bible.. its all a conspiracy by satan.. the bones we find are just mixes of elephants and alligator bones.

Indian Ocean... by cOdEgUru · 2004-03-02 05:04 · Score: 5, Funny

Indian Ocean eh?

I presume these Indians had something to do with the massive extinction of US Tech jobs as well?

First the poor dinosaurs, and now poor US geeks.. ............

And yes, I am Indian, the real deal, the kind Columbus went searching for..thankfully never found.

--
Rapid Nirvana

Re:Indian Ocean... by AndroidCat · 2004-03-02 05:14 · Score: 4, Funny

In ages to come, they'll dig up the bones of dot-coms and wonder what caused them all to die off at the same time.

--
One line blog. I hear that they're called Twitters now.

Not right by Reorax · 2004-03-02 05:06 · Score: 4, Funny

The second impact may have been in the Indian Ocean.

I always though the Second Impact was caused by one of the Angels...

No wonder I was so confused by the end.

--
This sig is only here so people stop skipping the last lines of my posts.

Re:Keller's Conclusions [weakly] Refuted by H4x0r+Jim+Duggan · 2004-03-02 05:06 · Score: 5, Informative

Kellers findings are pretty well founded. The idea is that the Chicxulub impact occurred during this warming period with severe environmental effects but the extinction of the dinosaurs - When the second impact finally occurred, it hit an already stressed community which was the straw that broke the camel's back. Almost anything could have wiped them out at that point. Jan Smits doesn't refute this very clearly - but I would accept that the theory is less sensational that it appears from the headline.

--
Please help publicise swpat.org - the software patents wiki

Yet another theory? by MissMarvel · 2004-03-02 05:07 · Score: 5, Informative

Ah.... The great K-T extinction debate continues....

For those interested in reading about the supporting data and possible causes of the K-T extinction,
here's a good discussion" by Dewey M. McLean of the Department of Geological Sciences,
Virginia Polytechnic Institute and State University.

Re:Yet another theory? by cluckshot · 2004-03-02 05:41 · Score: 5, Interesting

First my compliments to the author of the previous post. Obviously a person interested in a learned discussion. Secondly I would like to throw in a few more observations.

At Mile 282 on US I-65 in Alabama the KT Boundary is exposed in a Road Cut about 1/2 way up the cut. It is exposed frequently across Alabama. The following facts are observable by anyone looking at these sites.

[1] The site has contigious deposition of strata from well below to well above the KT Boundary
[2] The site has a crumbly rock/clay consistancy for some 20 feet below the KT Boundary
[3] The Rock is Sandstone for about 20 feet above and then is Limestone for about 60 feet.
[4] Above that mapping contigious strata are layers of coal, shale, and again limestone

All of these layers represent a contiguious geologic layering as they are essentially like pages in a book and of fairly consistent thickness over great distances. The presence of Limestone which has sea bed fossils brings into question exactly what we are seeing at the site. The reasons for this are multiple including the geologic age of the Limestone (Very Old) and the means of deposition of it (Sea Bed activity). I believe it would be quite fair to question very nearly any theory regards the KT Boundary. It is clear that the area was under the Ocean for a substantial period after the KT Boundary and it would appear that the KT deposition was fairly consistent with that event and possibly just one of many depositions layered this way. The fossil and other data from the KT Boundary area is inconsistent with any existing theory. The Limestone for example dates from early life times per Geologic Estimates about 600 Million Years. Yet it is above the KT Boundary.

These inconsistencies with existing theories need investigation as the area is one with a very substantial amount of data and has a very stable history geologically allowing the story to be read in order of events.

It can be safely said that the presence of the rocks above the KT Boundary are consistent with the continent being sunk below the ocean. Many rocks below this level hold the same data. The strata being so stable in deposition process showing large fairly even deposition layers calls into question exactly what happened to deposit the soft material and the KT Boundary. The sandstones above are similar to volcanic ash depositions.

--
Never Politically Correct ~ I prefer the facts If you don't like what I say, get a life, or comment yourself.
Re:Yet another theory? by geomon · 2004-03-02 06:47 · Score: 4, Informative

Pick up a primer on geology. Read the section on structural folds, faults, and plate tectonics. That will clear up some of your confusion.

Just for the record, I was standing on rock from the K/T boundary in Southern California, looking up 10 meters in the air at rock from the Precambrian. The section I was standing on was originally 10,000 meters of Grand Canyon sequence, attenuated 1000X, folded upside down, sheared off, and moved along northwest a lateral fault for 3.5 km.

--
"Rocky Rococo, at your cervix!"

I knew it. by hookedup · 2004-03-02 05:08 · Score: 5, Funny

See? The dinosaurs fell victim to outsourcing to india.

Re:Religious fanatics, unite! The end is very nigh by maxwell+demon · 2004-03-02 05:08 · Score: 5, Funny

Hmmm ... Kangaroos weren't mentioned in the bible as well. Nor was Australia. Probably the evil non-believers invented australia to hide the fact that earth really is flat :-)

--
The Tao of math: The numbers you can count are not the real numbers.

Why not a viral extinction? by BCGlorfindel · 2004-03-02 05:09 · Score: 4, Interesting

The obviousness of this question makes me suspect it is a dumb one to ask but maybe someone can clarify for me. Why is it so strongly believed that some kind of environmental change wiped out dinos and not some kind of disease/virus?

Re:Why not a viral extinction? by stratjakt · 2004-03-02 05:17 · Score: 5, Interesting

There are many theories..

The ones presented on a Discovery Channel special (it was about Mammoths, but close enough for government work) were;

"The big Chill" - the Ice Age froze 'em all. Popular among scientists.

"The big Kill" - hunted to death by humans, little evidence exists for this, popular with the tree hugging set.

and

"The big Ill" - wiped out by some sort of disease. There was some sort of microbal evidence from frozen remains presented for this one.

I remember hearing a disease theory about the dinosaurs, basically it had to do with the rise of mammals, prehistoric rats as a vector to spread the virus - modeled after the spread of Black plague.

Frankly, I don't care. I'm just glad they're extinct. I've seen Jurassic Park.

--
I don't need no instructions to know how to rock!!!!
Re:Why not a viral extinction? by Xzzy · 2004-03-02 05:21 · Score: 4, Interesting

> and not some kind of disease/virus?

Because there's always going to be a few who end up being immune and don't get infected.

Look at mosquitos for a good modern example.. bug spray manufacturer's have to update their formulas every few years because the bugs that survive end up being immune, and as they breed the entire population inherits the immunity.

Not that I'm an authority on the topic; I suppose a "super virus" could have nailed them and decimated the population so badly that even those who survived were unable to repopulate. So it's not to say a virus wasn't the cause, but it's not a convenient "deus ex" type solution.
Re:Why not a viral extinction? by KnightStalker · 2004-03-02 05:28 · Score: 4, Insightful

There were many groups of animals and plants that vanish or change radically at the K/T boundary, not just dinosaurs. It's possible that a virus would kill off one species. The likelihood decreases, I suspect, as you add more and more loosely related groups. It seems more likely that environmental change killed all of dinos, nautiloids, lots of mammals and birds (even though most survived, some did not), plankton, etc., than that a plague did it.

--
* And remember, it's spelled N-e-t-s-c-a-p-e, but it's pronounced "Mozilla."
Re:Why not a viral extinction? by Muad'Dave · 2004-03-02 05:36 · Score: 4, Funny
You forgot:
- The big "Spill" - prehistoric tanker of this new substance tentatively named "oil" runs aground, killing everything.
- The big "Krill" - mutated giant sea creatures crawl from the sea, killing everything.
- The big "Dill" - giant pickle falls from the sky, killing everything.
- The big "Grill" - Eddie Murphy and his uncle Gus start a massive fire using "2 millions gallons of gasoline and half a continent of wood", killing everything.
- The big "Quill" - Giant porcupine goes on a rampage, killing everything.
- The big "Still" - Ancient life discovers the pleasures of ethyl alcohol, killing everything.
- The big "Thrill" - Michael Jackson ... [deleted], killing everything.
- The big "Drill" - While searching for the aforementioned "oil", Halliburton from Planet X accidently drills thru Earth, killing everything.
- The big "Frill" - Too much influence from "Queer Eye for the straight Guynosaur" causes birth rates to plummet, killing everything.
- The big "Phil" - A well-known talk-psychiatrist rolls over on a whole generation of dinosaur eggs while sunning himself, killing everything.
--
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.

Another suggestion by TobiasSodergren · 2004-03-02 05:09 · Score: 5, Interesting

... is that practically all dinosaurs that lived after the first impact were dead before the second hit earth ;)

Second Impact? by orpheus2000 · 2004-03-02 05:13 · Score: 4, Funny

The second impact may have been in the Indian Ocean.

I had always thought the Second Impact was in Antarctica when Adam got pissed and melted the entire continent.

Deccan Traps? by Anonymous Coward · 2004-03-02 05:19 · Score: 5, Interesting

The article doesn't seem to make any clear connection between the climatic stress - warming - supposedly caused by the eruptions that created the Deccan Traps and any meteorite. The accompanying graphs show a steady climatic cooling trend in the late Cretaceous and that curve doesn't appear to be affected by the iridium yeilding event. The biological diversity however correlates pretty muc exactly in geological time. So, where are the linking data that make sense of this article?

Re:Religious fanatics, unite! The end is very nigh by back_pages · 2004-03-02 05:22 · Score: 4, Interesting

And these who pervert the purpose of religion are also forced to admit that Asian people must have been created by Satan else acknowledge the duality of the Bible and reality. It's easy to dismiss penguins, kangaroos, and Australians as the work of the devil, but to realize that one's faulty religious beliefs actually demand full fledged racism against the majority of the world - fully contradicting the teachings of Jesus Christ - is sometimes exactly the brand of clue stick needed.

Remember, Jesus taught us to love all of God's children. Those pesky Asians couldn't possibly be God's children if the Old Testament is an accurate account of history. Noah's flood must have wiped out all of those destable foreigners, except that the Chinese had a society at the time with written history that has no details of an unusual flood.

Even more eye-opening is the fact that literal interpretations of the Bible are extremely new. Such intellectual hobbling wasn't popular until the 19th or 20th century - for almost 2000 years Christians realized what the purpose of the Bible was, only recently did some of them shut off their God given faculties and prescribe to a system of belief founded on utter and incredible ignorance.

Re:Religious fanatics, unite! The end is very nigh by back_pages · 2004-03-02 05:24 · Score: 5, Funny

I was only kidding about the Australians - forgot to add that as a PS on the last post. Kangaroos definitely do the bidding of the Prince of Darkness, though.

Conspiracy theory by Anonymous Coward · 2004-03-02 05:27 · Score: 5, Funny

There must have been a second asteroid.

After all, everyone knows that the JFK 'Second Gunman' Theory is 100% accurate.;-)

My vote is... by PhatKat · 2004-03-02 05:37 · Score: 5, Insightful

There seems to be a popular opinion that humans are the most evolved of all species... that statement is totally bogus for a number of reasons, but if you define most evolved as best adapted to surviving whatever its environment throws at it (the galactic environment you could say), you just can't beat single celled organisms. The more adapted you are, the more you depend upon the situations and circumstances that make those adaptations beneficial. If we have a true Armageddon, I'm voting for the bacteria that live in deep sea volcanoes... it doesn't even need the Sun's light to survive.

Re:The Flat Earth Society by jbrader · 2004-03-02 05:41 · Score: 5, Insightful

I think it's incredibly ironic somewhere right now there is probably someone using a satellite link to look at the Flat Earth Society web site.

--
You are so boring that when I see you my feet go to sleep.

He deals with that by Von+Rex · 2004-03-02 05:45 · Score: 5, Informative

Check out his reply to the original article.

There's a picture of the soil sample he's talking about, too.

"The best evidence in favour of a single impact, I repeat, is in the K/T record from the US western interior. In numerous outcrops from Alberta in Canada, through Dogie Creek in Wyoming to the Raton Basin in New Mexico an iridium-enriched clay layer occurs in coal swamp deposits at the palynological K/T boundary. This clay layer has a dual nature (Izett, 1990), and consist of two layers: a lower layer that contains spherules (best seen in Dogie creek (Fig. 7) morphologicaly indistinguishable from the Chicxulub spherules from the Gulf.

The upper layer is strongly enriched in iridium and shocked minerals, such as quartz, feldspar and zircons. The shocked zircons are shown (Krogh, 1993) to have the isotopic properties (Sm/Nd) of the pan-African basement of the Chicxulub crater. In all the mentioned localities the two layers are in contact with each other, without an intervening layer. Not even a single layer of one fall season of leaves or plant material occurs between the two layers. If the upper, iridium-rich, layer is from another impact than the Chicxulub impact, they have to be simultaneous, and have to occur on the same pan-African basement - in itself highly unlikely, but not impossible. A 300Ka separation between the two layers in all the localities, as Keller posits for the separation between the Chicxulub impact and the iridium producing impact, is therefore excluded - barring a miracle."

What happened to the nickel theory? by Anonymous Coward · 2004-03-02 05:47 · Score: 4, Informative

Could it be that this second meteorite was rich in poisonous metals, tainting the soil world-wide for years to come? This article is interesting, but I have not seen mention of the theory elsewhere.

Re:Religious fanatics, unite! The end is very nigh by werfele · 2004-03-02 05:49 · Score: 5, Insightful

I'd be the last to propound a literal interpretation of the Bible, but I believe the traditional interpretation of Genesis is that all of humanity is descended from Noah's children. Asians are presumed to be the descendants of Shem. You'll have to look for the origins of racism elsewhere.

That theory is still controversial by Von+Rex · 2004-03-02 05:56 · Score: 5, Insightful

The abiotic theory on the origin of oil, while politically convenient to certain groups due to it's consequence of almost unlimited oil reserves, is still highly controversial. It is not reasonable to expect it to be taught as fact in textbooks for a long time, if ever.

Dutch radio interview by Trestran · 2004-03-02 05:58 · Score: 5, Informative

For the Dutch slashdotters; Jan Smit said something about it on the Dutch radio(it's about 10 minutes into the stream), where he basicly called everything said by Kellar bullocks("a lott of mud throwing" and "facts that are verifiably wrong").

He has one of the samples of this study was based on (and (acording to above mentioned radioshow) the who divided up the original). In the end of the radiointerview he sugests letting all the original drill samples be tested by a third party for magnesium or calcium to prove if what Kellar has found are actual organism or just cristaline structures (as Smit seem to think). Sounds good to me, but then IANAPaleontologist.

Cause and Effect? by boojum.cat · 2004-03-02 06:25 · Score: 5, Interesting

What has bothered me for a long time about the Chicxulub theory is that nobody ever provides evidence linking the impact to the extinction. Every time new evidence appears indicating that there was an impact, it's reported as being new evidence that the dinosaurs were wiped out by it. Actually, all it shows is that there was an impact of some sort.

Years ago I read Robert Bakker's book, 'The Dinosaur Heresies". In it he claims that the fossil evidence shows that the dinosaurs were in decline long before the KT boundary and the appearance of its famed iridium layer. Furthermore, many species survived the extinction, and some of those species (such as amphibians) were ones that you might expect to be particularly susceptible. So although the impact might have contributed to the mass extinction, it's not likely to have been the root cause.

--
Lost: one sig, witty, 120 chars, sentimental value. Reward offered.

A new theory? Probably not the last by geomon · 2004-03-02 06:37 · Score: 4, Interesting

When I was an undergrad geology student 20 years ago, the prevailing theory of how dinosaurs went extinct involved an asteroid hitting the Earth on the Atlantic Ridge system. The target location would be the present-day island of Iceland. The evidence used to support the conclusion included iridium-soaked sediments ringing Iceland dated right at the Mesozoic/Cenozoic (K/T) break, the high concentration of ultramafics at the surface, etc. etc.

The problem for this theory was (is!) the chain of events that would have led to a mass extinction. The theory assumed that the explosive force of the impact would have kicked up large amounts of dust and moisture, which would reduced solar activity and stunted or halted sufficient production of vegetative matter. That would have led to the die-off of herbivores, which in turn would have led to carnivore die-off. The hitch? Insufficient evidence of mass flora extinction at the K/T boundary.

Some years later, the location of the impact changed to Mexico, but the mechanics stayed the same. But there is still a huge lack of vegetative data to support a mass extinction.

So now there are several asteroids hitting the Earth. Did that change the fundamental assumptions?

Nope.

I'm glad the debate is still alive. Nothing bothers me more than a theory that attempts to tie everything together in a neat package.

--
"Rocky Rococo, at your cervix!"

Ask the turtles and crocs about "cold" blood by ianscot · 2004-03-02 06:40 · Score: 4, Interesting

...being cold blooded they are less resistant to climactic change. A period of dynamic weather, with patterns changing faster than migration could handle, would tend to be very bad for anything cold blooded.

Turtles and crocodiles seem to have survived the mass extinction(s) of the dinosaur age quite well. Both are ectotherms, neither migrates especially far. The general "coldbloodedness = vulnerability to the extinction" correlation just plain isn't there. The major case we're talking about, the dinos, is an open question to start with -- cold-blooded? Endotherms? Somewhere in between? Varying by species?

Something on the scale of the impact we're talking about would have all sorts of indirect effects. Mass extinctions, too, are going to be complex events, which is one big reason to be skeptical of any single-impact idea. For my money, what we have is a correlation -- not a causal link we can describe in concrete ways.

The model I always think of is Krakatoa's eruption in 535 AD. Global climate change kicked in just after that -- years without any harvest in Europe, extreme volatility. There are people who think that eruption changed human history: ushered in the "dark ages," partly caused or influenced the rise of Islam, destabilized governments, and so on. Maybe so -- but this is an event well within recorded human history, and it's still pretty doubtful trying to connect all the causes with their effects. That's if we accept the volcano -> weather changes link to start with.

Simple biological example: take ammonites and nautiloids. Similar chambered-shell mollusc floaters, right? Why did ammonites die out after the crateceous event, while at least a few nautiloids didn't? Ammonites were by far the more dominant critters before the extinction. Were there differences in their reproductive strategies, so that Nautiloids could "wait out" a bad phase better? What? It just ain't that simple.

(As far as mammals eating sleeping dinos at night, there were early mammals for a long time during the age of the dinosaurs. The jurassic, at least.)

--
"Fundamentalism" isn't about divine morality. It's about human authority.

Misuse of Probability by Winkhorst · 2004-03-02 07:26 · Score: 5, Insightful

The only thing I really have trouble with is the Carl-Saganish misuse of probability. The fact that something happened once doesn't make it any less likely to happen the next day. The odds remain the same.

The second misuse of probability here is the assumption that there's no causal relation between the two events. They are simply treated as random occurrences, which fact is not in evidence. For all we know the two meteors could have been parts of the same original object on the same orbital path.

--
"Is this Winkhorst a nova criminal?" "No just a technical sergeant wanted for interrogation."

Slashdot Mirror

End of the "Lone Asteroid" Theory?

51 of 306 comments (clear)