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Re: From Science News



Garrison Hilliard wrote:

NEW THEORY ON DINOSAURS: MULTIPLE METEORITES DID THEM IN
from The New York Times

'New theory'? Actually, it's a hypothesis, not a theory, and one that has been around for many decades. Once again, the commercial media betrays its complete and total inability to comprehend even the basic aspects of the science most people rely on them to explain.


For more than a decade, most scientists have believed that the extinction
of the dinosaurs was caused by a single event: the crash of an immense
body from outer space,

True, I suppose. What they fail to mention is that 'most scientists' -- including, I might emphasise, the Alvarezes -- are in completely unrelated fields of specialisation and know as little (or less) about dinosaurs as (than) the general, non-scientifically-educated public. What about a statistic that takes into account the fact that there are many different fields within the incredibly broad rubric of 'science', that no one has enough time to specialise in *everything*, and that most scientists take the word of others to dictate their beliefs about fields outside their specialties? What should be relevant is what *dinosaur* scientists believe, not what some mythically monolithic 'most scientists' believe. And among dinosaur scientists, the issue is a lot more controversial, which is a strong circumstantial implication that the evidence for a direct connection is not as firm as it is portrayed by media outlets run by people who understand nothing of science but everything of how to excite people into giving up money to them through inflated and sceptically unexamined rhetoric.


Now, however, scientists working in Ukraine have discovered that a well-
known but smaller crater, some 15 miles wide, had been inaccurately dated
and is actually 65 million years old,

I'm not susprised. In fact, I thought there were always a number of craters of about K-T-border age, and that the only reason Chicxulub has been singled out is because it's the biggest one -- the only one large enough to even *potentially* or *possibly* or *hypothetically* cause a mass extinction.


making the blast that created it a likely contributor to the end of the
> dinosaurs.

How could this *possibly* follow? It's based only on assumption: A bolide hit 65 million years ago, therefore it probably killed the dinosaurs. I don't accept the evidence for that even with Chicxulub, but at least I recognise that's based on other evidence besides mere coincidence in time,including shocked quartz, tektites, iridium, and mathematical models of the possible results of an impact of the same size. Unless the New York Times is being even more pathetically incompetent than I have already indicated, and is inexcusably leaving out highly relevant and important parts of the story, there is not yet any of this other corroborating evidence for this other impact being related to the extinctions -- it's based merely on a single calculation saying it happened at the right time.

Since when does coincidence in time count as scientific evidence of not only a correlation but a (partial) *causation*? There have been a LOT of bolides that have hit Earth all through its history -- many MANY more than can be made to coincide in a one-to-one or even multiple-to-one correspondence with mass extinctions -- not to mention that there are many more extinctions that are not considered 'mass' at all but differ from the traditional 5 or 6 mass extinctions only in being slightly smaller in magnitude and slightly higher in frequency -- exactly as one would expect from some sort of random statistical distribution resulting from factors purely *internal* to a nonlinear process like evolution.

(I am just waiting for someone to try to prop up the bolide-extinction connection by putting these two objections [that there are many other extinctions that cannot be qualitatively separated from the few mass ones, and that there have been constant bolide impacts of various sizes throughout Earth history] together and suggesting that ALL extinctions of 2 or more species within a single 5-million-year period are caused by bolide impacts, smaller impacts for smaller extinctions and larger ones for larger extinctions -- the ultimate reductio ad absurdum of the extreme partisan bolide-hypothesis position, which would ultimately amount to a rejection of all understanding of evolution and natural selection as biological processes, pinning all deviations from the old-fashioned straight-line 'Scala Naturae' progression leading towards humans on outside factors and not on the inherent unpredictability and complexity of biological evolution. In other words, just as with doctrinaire religion, all understanding based on factors we know and have experimental data for is rejected in favour of an unquestioning 'faith' in an external power that cannot be explained except in broad generalities and claims to ignorance. The fact is, we know that there is a broad nonlinear statistical pattern of extinctions throughout history, and another statistical pattern of bolide impacts, and no one has yet been able to match the two up to anywhere near the degree needed to imply even correlation, let alone causation, unless someone published a VERY significant finding somewhere that was totally ignored by both the commercial media and the scientific community.)

It might do the sense of humility of the New York Times people some good for someone to write in and point out to them that there have been hypotheses about multiple K-T impacts since before the Alvarez findings, and such hypotheses have not caught on for a good reason: those species strong enough to resist one impact would be very likely to be able to survive additional impacts equally well, and those vulnerable to later impacts would have already been killed by the first one. There would be a few exceptions, of course, examples of the 'final straw - camel's back' phenomenon, but as far as I can tell no one has provided any evidence that a series of successive impacts would be discernably different in its results than a single massive impact.

Of course, these Ukraine scientists may be proposing that two impacts happened at ONCE and caused the extinctions. But that makes about as little sense -- if the Chicxulub impact was powerful enough to cause a mass extinction itself, what would it mea to say that this other smaller impact was also a 'cause' or 'contributor', without evidence that the effects of Chicxulub + this one would be different from the effects of just Chicxulub?

--
--Sean
http://www.livejournal.com/users/spclsd223/