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Sunday, April 24, 2011

Crick’s Joke

Chapter 6G

Crick’s Joke

I was unable to secure permission from the Journal of Cosmology to publish in this blog the 24 commentaries on Richard Hoover’s claim to found cyanobacteria in several meteorites. The gentleman who replied did, however, invite readers of the blog to take a look at the journal. These are the references. The online version is free.

Journal of Cosmology, 2011, Vol 13, March, 2011

I should add that the Journal of Cosmology has devoted several issues to panspermia and related topics. I will have to take a look and may perhaps return to this subject in a future posting.

In the meantime, however, I would like to remark, almost in passing, why the whole panspermia movement seems so perplexing to me. I will begin by expressing a nagging doubt about Hoover’s Cyanobacteria claim. From what I could tell, although as I said I will have to read more, Hoover’s claim seems to be based on the physical similarity between the structures he found in meteorites and Cyanobacteria in our planet. The “alien” pedigree is established by the fact that such structures exhibit only 8 of the 22 amino acids we would expect in terrestrial life. It seems to me, then, that even if those structures were indeed fossils, it is a long stretch to classify them as Cyanobacteria. Clearly, they cannot be Cyanobacteria: they don’t have the same proteins, for they don’t have the same amino acids, thus they cannot be the same kind of beast. Think of it another way: they must have radically different proteins, therefore, since genes code for proteins, they must have radically different genomes. Perhaps the classification is given because those structures, when alive, if they were ever alive, also engaged in oxygenic photosynthesis. But I do not know how that could be established from physical similarity.

Now, most defenders of panspermia promote the idea that terrestrial life did not originate on Earth but came from elsewhere. One wonders what kind of evidence they could have for such a claim. It is normally based on two assumptions:

(1) That life could have survived journeys of millions of years before landing on our planet;

(2) That life could not have started on Earth.

The first assumption is bolstered now by Hoover’s evidence for Cyanobacteria. But as I pointed out in my previous posting, Hoover’s findings do not support the notion that terrestrial life came from somewhere else, since presumably they established that those structures are not relatives of terrestrial life forms at all (only 8 amino acids in common, etc.).

The second assumption is rather astonishing. We really do not know how life begins. So how can these people argue that life could not have begun here?

They say that there was no enough time for life to evolve here from organic compounds, that the conditions were not right, and so on. But their reasoning seems very faulty to me. I will try to lay out my objections with some care in my next posting, and perhaps some readers who disagree with me can spot faults with my own reasoning and thus improve my understanding.

I would like to add at this point, though, that some of the more specific claims made by the advocates of panspermia make them lose scientific credibility. I will merely mention a couple that I found in a side article by Lana Tao in issue of the Journal of Cosmology that began this detour a couple of postings back. I will point out next time why they are not scientifically credible.

C. Wickramasinghe: "What we have developed and proposed in this text is a cosmic theory of evolution which completely overturns Darwinism." This appears in a section titled THE DEATH OF DARWINISM, no less.

R. Joseph: “Evolution is not random but is instead the replication of creatures which long ago lived on other planets."

R. Joseph: "Just as apple seeds contain the genetic instructions for the growth of apple trees, these genetic seeds of life contained the DNA-instructions for the Tree of Life, and the metamorphosis of all life, including woman and man: the replication of creatures which long ago lived on other planets."

I will close by remembering Francis Crick funny account of why we will never be able to figure out how life began. Life came to Earth from another world. In that world, scientists developed a synthetic form of life that could withstand the long journey through space. But such life could have never arisen naturally. So by studying natural phenomena, we will never get a clue, for the conditions necessary to bring such life into existence do not naturally exist.

And Gunther Stent quipped that if Francis Crick, the greatest biologist of the 20th Century had not been able to discover how life began, no one could.

But on the shoulders of giants….

1 comment:

Aimee said...

I have always wondered how people who claim that life came to Earth from another planet try to explain how life arose on the other planet itself. All they succeed in doing is to move the question of how life, in general, began, to a place where there can be nothing except speculation; which, granted, may be intentional, in order to circumvent any problems they haven't solved with other theories, but all they are really saying is "We have no idea how life originated."