Dino-impact theory takes a hit
Published: 8 February 2006 (GMT+10)
9 March 2004
An asteroid killed the dinosaurs. Why, ‘anyone knows’ that even the ‘smoking gun’, the actual impact crater, has been identified—called Chicxulub, on Mexico’s Yucatan Peninsula. For years, this has been ‘received truth’ in our culture.
Sadly, most people are ignorant of how historical science works. They are particularly unaware of its limits, of the way in which, of necessity, fragile towers of speculation are built upon layers of assumptions, unable to be directly tested. They confuse such science with the operational, experimental science (investigating how the world works) that has given us modern medicine, jet airliners and the like.
Not all evolutionists accepted the dino-impact theory. TJ reviewed a potent critique of it—a book by an evolutionary geologist and a Skeptics member/journalist.1 The authors pointed out that the geological evidence at Chicxulub did not ‘fit’.
Nevertheless, the bandwagon rolled on from strength to strength until it became ‘scientific fact’. Fashion and peer pressure play an important part in the truth-claims of historical science. Dinosaurs have always been appealing; combine their fierce and mysterious image with the awesome notion of a ‘killer asteroid’, mix in a dash of apocalyptic fears of a nuclear winter and you have a recipe for a myth with powerful psychosocial … er … impact.
So it is no surprise, really, that it took a while for the first noticeable cracks in this popular story to begin to appear. A recent analysis of the famed crater has concluded that the ‘dating’ was out—by a mere 300,000 years, mind.2 The authors do not deny that the Chicxulub crater may well have been from an impact. But on their timescale assumptions, this impact had to have occurred long before the ‘time’ when the last of the dinosaurs are said to have died out.
This announcement has triggered considerable turmoil. Some are challenging the findings. Others are saying that maybe the Chicxulub impact started a process of global instability that eventually led to the dinosaurs’ demise. So what finished the job, hundreds of millennia later, in this framework? The famed iridium layer,3 coinciding with the ‘transition’ in the fossil record from dinos to no-dinos, has some talking of another impact. (Except that no-one has yet found a crater which ‘fits the bill’.) Others say that the agency which completed the job that Chicxulub allegedly started was global warming and/or massive volcanism. But then, since volcanism is known to be able to cause an ‘iridium layer’, maybe there is no need to invoke an impact at all?
How will anti-creationists respond to whatever eventual adjustments are made to the ‘standard picture’ of dinosaur extinction? If they remain true to form, they will probably try to take the (moral?) high ground by pointing to this as an example of the ‘self-correcting’ nature of science. But this fudges over the fact that we have no more reason to accept any new ‘adjustment’ as ‘correct’ than we did the original scenario. This ‘re-dating’ itself is—can only be—just as speculative, just as based on fragile and fallible assumptions, as the original. Unfortunately, Christians, too, are regularly dragged into swallowing these popular reconstructions as factual. They are too often oblivious to the fact that such scenarios, presented as ‘truth’, undermine the historicity of the Bible, and thus their whole Gospel foundation.
There is an important, obvious lesson in these mounting revisionary pressures in the dino-impact story. All such historical reconstructions, no matter how popular or widespread, should never be confused for ‘fact’. The same is true of the latest ‘correction’, even if it becomes widely accepted.
When it comes to what really happened in the history of our planet, the fleeting fancies and fashions of fallible, fallen, (and mostly philosophically naive) mankind are a poor substitute for the straightforward, powerful Word of God Himself. Dinosaurs were created on Day 6 of Creation Week. Two of every kind went on Noah’s Ark. The rest drowned in the Flood, many of them becoming preserved as fossils. After the Flood, those preserved on the Ark multiplied and their offspring spread over the earth. In subsequent centuries however, dinosaurs did go extinct, probably for the same sorts of reasons other animals still go extinct today [see Q&A: Dinosaurs].
References and notes
- Officer, C. and Page, J., The Great Dinosaur Extinction Controversy, Helix Books, Massachusetts, 1996; reviewed in TJ 12(2):154–158, 1998 (see Did a meteor really wipe out the dinosaurs?). Return to text.
- Keller, G., and six others, Chicxulub impact predates the K-T boundary mass extinction, Proc. Natl. Adad. Sci., USA, 10.1073/pnas.0400396101; published online <www.pnas.org/cgi/content/abstract/0400396101v1>, 2 March 2004. Return to text.
- This refers to the finding that often, between rocks classed as Cretaceous and those of Tertiary category, there is evidence of enrichment with noble metals such as iridium and osmium, which are commonly found in objects from outer space. They are also found in volcanic emissions. In long-age interpretations of geology, this ‘K-T boundary’ (K = Cretaceous, from the German word for chalk, Kreide = chalk, T = Tertiary) is the time in which the dinosaurs disappeared. The iridium layer became the trigger for the belief that an impact from outer space helped wipe out the dinos. When the alleged crater responsible was found, and linked to the K-T iridium layer, skeptics of the theory were largely howled down. Return to text.