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End of the "Lone Asteroid" Theory?
hussar writes "This BBC article reports on research that suggests the dinosaurs were not killed off by the Chicxulub asteroid's immediate effects but ultimately fell to evironmental stresses caused by a second asteroid that hit about 300,000 years later. The second impact may have been in the Indian Ocean."
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....
When the K-T boundary impact finally came, it hit an already stressed community... almost anything could have wiped them out at that point
I don't know what to believe in anymore.
There are plenty of evidence suggesting man and dinosaur living side to side with one another at one time. Fossils of human and dinosaur foot steps found next to each other are alot more common than giant asteroids found in the Indian ocean.
Just like geology shows the egypt spinx head and body show different types of weather pattern damages.
There is too much contradictions to buy into one theory.
Veni, Vidi, Velcro!
Because while viruses can and do affect huge populaces, they rarely wipe out entire species so thoroughly. A virus that is too strong and leaves no one standing doesn't spread very far.
Do you have any papers you could recommend that discuss this behaviour?
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.
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."
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?
Not likely.
The disease would have to act slowly enough to allow for it to be spread over the entire planet without killing the carriers too soon. And, there would be areas where dinosaurs would have been isolated (except by air) due to changes in earth formations such as valleys & large rivers temporarily trapping dinosaurs in specific areas. Those dinosaurs should not have been infected.
The disease could have been carried by flying dinosaurs, but the chances of them covering every location on earth before dying isn't likely.
Not to mention, the virus would run into resistant dinosaurs due to species differences.
This is not a dream, not a dream...we are transmitting from the year 1-9-9-9.
Ah, good old mindless Christian(ity) bashing...made especially amusing since other scientists are already disputing this theory. (Check a few posts up ;) To be blunt, many theories that have come out of scientific circles are at least as stupid as the theories that you are "presenting". Quit whining, Christians don't have a lock on being morons.
I think some of you need to do a better job of keeping up with what the religious fanatics believe. Do you really think your arguments trying to make pinprick holes in their belief system haven't been answered countless times before?
There is an answer to multiple races.
There is an answer for the dinosaur extinction.
They do believe dinosours existed.
Please don't make yourselves look like fools talking about stuff you don't know anything about. Keep your reputation high by talking about geek stuff which you know best, not religion. Your arrogance is amusing.
Of two meteors, one near-extinction level, the second not-quite-but-enough-to-finish-them-off level, within 300,000 years?
Personally I say slim and none. 300,000 years is a fucking long time. Remember where humanity was 300,000 years ago (hint: not exactly homo sapiens sapiens). Whatever near-cataclysmic damage the first meteor did, nature would have moved on. If the first meteor didn't wipe them all out, the ones that did survive would also have been those with the best odds against the second meteor. So, it doesn't really make sense.
Kjella
Live today, because you never know what tomorrow brings
Not only would it have to wipe out all of a single species, this virus would half to jump from species to species. Almost all the life on the planet went extinct in a short period of time. So this virus would have to affect different species of animals and plants. I find the asteroid theory easier to swallow.
Jack Valenti and Orrin Hatch will be first up against the wall when the revolution comes.
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.
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.
You have to keep in mind that humans are one of the few bare mammals. Also that as we're mobile and adaptive, we can live as well in the arctic as the equatorial by modifying living habits, clothing and shelter. Mammals in their native habitat are pretty well tuned to survive its extremes.
A feeling of having made the same mistake before: Deja Foobar
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.
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.
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.
Innocent until proven guilty, my friend. If you want to refute them, post evidence. Otherwise, you're doing the same thing that they are.
... (including the Bible). Say something, offer no proof.
I also vehemently profess, that Jesus was a woman, smoked pot, and lived to bear 18 children, the bloodlines of which are present in all of our governments' heads.
People believe that, too. I swear, it's true. Don't belive me? Look it up yourself.
It's the oldest trick in the book
Oh, hell no. This is a perennial windmill to be tilted at. There's an alternate hypothesis presented every year or so, and not because the most widely accepted hypothesis doesn't do a good job of explaining the data. It's one of those unanswerables that you can make your professional mark on by going up against it. As in boxing, you don't have to win against the champ, you just have to last enough rounds.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
That some were found to nest suggests more than simply protecting the eggs, they were keeping them warm.
Modern reptiles, such as crocodiles, lay eggs in nests. So do fish. I don't think that really says much one way or the other about the issue.
"The big Chill" - the Ice Age froze 'em all. Popular among scientists.
I'm really skeptical that a mammoth extinction caused by an Ice Age is popular among scientists. Mammoths seem to have been well adapted for the cold and died off when the climate became warmer.
"The big Kill" - hunted to death by humans, little evidence exists for this, popular with the tree hugging set.
There is plenty of evidence for human involvement in extinctions of mammals such as the mammoth. The models demonstrate that it doesn't take a whole lot of hunting to drive a population of large mammals to extinction.
FreeSpeech.org
You misunderstood him. He said the eggs were on the surface, not buried, meaning that body heat was required to keep them warm. Cold blooded reptiles bury their eggs in the ground or under mounds, and the egg's temperatures are thus regulated. Hence, eggs on the surface, in nests, implies that these animals were like birds, and were warm blooded.
And you are quite certain that the extra 3% that we put into the air is not harmful? Pray, back that up with a fact.
J'aime mieux les méchants que les imbéciles, parce qu'ils se reposent. -- Alexandre Dumas
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."
Extinctions on the continents
The only groups for which a detailed record of change has been established are terrestrial and aquatic vertebrates and plants, to which discussion must accordingly be confined. However, it is worth noting that for the extremely important and diverse insect faunas, for which the fossil record has improved considerably in recent years, there are no indications of any significant change across the K-T boundary (Labandeira and Sepkoski 1993). Nor is there any good evidence of an extinction event among birds (Chiappe 1995).
Vertebrates
Although they attract the greatest popular interest, dinosaurs are one of the least satisfactory groups for this kind of study, because of the paucity of suitable stratal sections and the comparative scarcity of fossil material. Virtually all the conclusions that have been drawn about the final dinosaur extinction episode derive from a few sections in the North American Western Interior, arguably the only complete succession of vertebrate-bearing strata across the K-T boundary, with the best sections being in eastern Montana. For all we know, the group might well have gone extinct in other parts of the world before the end of the Cretaceous, or even locally have persisted into the Palaeocene. In any case, too much has been made of the end-Cretaceous dinosaur mass extinction as a unique event. In fact, as Padian and Clemens (1985) have pointed out, the dinosaur generic turnover rate was exceptionally high throughout the group's history, and the most unusual feature of the end-Cretaceous event was the failure of a new replacive group of dinosaurs to emerge. The implication of the high generic turnover rate is that dinosaurs were always relatively vulnerable to extinction throughout their long history, and that no environmental event of exceptional magnitude need necessarily be invoked.
Mass Extinctions and Their Aftermath, A. Hallam and P.B. Wignall
Astronomical events happen on astronomical timescales, so if you accept the argument that even one dinosaur killer asteroid managed to get its orbit disrupted sufficiently to head our way, then there would most likely have been a few more disrupted by whatever caused that disruption, and/or by consequent events.
Now you put a large enough asteroid in an earth intersecting orbit, and ask yourself just how long it will take to either collide, or have its orbit further disrupted by a sufficiently near miss, and, I suspect, estimates of the order of hundreds of thousands of years would not be unreasonable. There is a lot of space out there.
(I still like the notion that there might have been a brief flourishing of technological dinosaur society which decided that the best way to benefit from the resources in the asteroid belt was to move some nearer to earth, but can't seriously imagine that there would be no other surviving evidence of such a society.)
One more reason to go back to the moon permanantly is so we can do a proper age census of significant craters where the archive isn't subject to plate tectonics.
-- Our systemic servants do not good masters make.