When 33 scientists released their interesting paper “Cause of Cambridge Explosion – Terrestrial or Cosmic?” the paper received fairly little attention. That's too bad, because it was an interesting paper fearlessly challenging biological orthodoxy. But now the paper has attracted new attention. Inspired by a speculation in the paper by the 33 scientists, someone released a news story with a headline saying octopuses may have come from space. The excitement may have got started with this outrageous headline from the British tabloid Express:
The tabloid's dubious headline
This, of course, was not actually “science news,” but merely a report about a very speculative idea presented in the paper about the Cambrian Explosion written by the 33 scientists. Let's take a look at the wider theory advanced by these scientists, and some reasons why it comes up short.
The theory is that various biological innovations in Earth's past occurred after comets dumped biological material on our planet. One of the great unsolved mysteries of biology is why there was such a massive amount of biological innovation occurring about 540 million years ago in the event called the Cambrian Explosion. During this relatively short period of time, most of the animal phyla now existing originated. For reasons discussed here, such an event has always been hard to reconcile with Darwinian ideas of slow, gradual evolution.
The 33 scientists suggest a strange possibility: that life originated in comets, and that during the Cambrian Explosion our planet may have passed through a cloud of comets. If life had existed on many of these comets, this may have provided our planet with a surge of new biological information. The authors state the following:
It takes little imagination to consider that the pre-Cambrian mass extinction event(s) was correlated with the impact of a giant life-bearing comet (or comets), and the subsequent seeding of Earth with new cosmic-derived cellular organisms and viral genes (Hoyle and Wickramasinghe, 1979, 1981). There may indeed have been a complex comet debris stream implying multiple impacts over the estimated 25 million years at the start of the Cambrian explosion.
The authors also suggest that cometary impacts had something to do with the origin of the octopus. The authors point out that “the genome of the Octopus shows a staggering level of complexity with 33,000 protein-coding genes more than is present in Homo sapiens.” The authors state this:
The transformative genes leading from the consensus ancestral Nautilus (e.g. Nautilus pompilius) to the common Cuttlefish (Sepia officinalis) to Squid (Loligo vulgaris) to the common Octopus … are not easily to be found in any pre-existing life form – it is plausible then to suggest they seem to be borrowed from a far distant “future” in terms of terrestrial evolution, or more realistically from the cosmos at large. Such an extraterrestrial origin as an explanation of emergence of course runs counter to the prevailing dominant paradigm.
Later the authors state the following, using “bolides” as a synonym for comets:
It is certainly an interesting idea that various “information explosions” or “complexity explosions” we see in the history of life might be explained by biological material coming from comets. And the 33 authors are quite right in hinting that such cases are inadequately explained by Darwin's theory of evolution, which offers only the explanation of random mutations and natural selection, one that is weak and unconvincing for reasons discussed here. An event such as the Cambrian Explosion in which we see the rather sudden appearance of most of the existing animal phlya (with so many new body plans appearing suddenly) is something that seems to be impossible to explain while you are confined by the straight-jacket of Darwinian orthodoxy. However, there are two very big problems in the type of theory suggested by the 33 authors.
The main problem has to do with the genetic code. The genetic code is the very specific system of representations used by all earthly life. It is not at all true that this genetic code follows inevitably from some laws of chemistry. The genetic code used by earthly organisms is only one of thousands of possible genetic codes that life might have been based on.
The genetic code
So let us imagine that life appeared independently on different comets in our solar system. The life on each such comet would have its own genetic code. If life were to develop on a comet, and that comet were to crash to our planet, such life would be using a genetic code entirely different from that of the earthly life that existed before. If there had been multiple collisions of life-bearing comets on Earth, what we would expect is a variety of organisms using different genetic codes. It might, for example, be that 50 percent of life used one genetic code, and 20 percent of life used some other genetic code, and 30 percent of life used some third genetic code. Or there might be ten different genetic codes used by earthly life. But that's not what we see. All life on Earth seems to use the same genetic code.
A writer named Gert Kortof states the problem in reviewing a book by Fred Hoyle:
Why is it a problem that the genetic code of the extraterrestrials and terrestrials should be the same? Is the code not necessarily derived from the laws of chemistry? No, it isn't! The genetic code is not a universal cosmic code. The problem with any theory that claims extraterrestrial genetic input, is that life on Earth is a closed genetic system. I strongly disagree with Hoyle's claim that "terrestrial biology is not a closed system". (p. 3) Why? All Life on earth happens to have the same genetic code. That would be no problem, if it would be the only possible genetic code available to life. Our genetic code is one of billions and billions of possible codes. The current one looks like a 'frozen accident'. The probability that the genetic code of extraterrestrial DNA is the same as the genetic code on earth, equals the chance that a Boeing-747 arises from a junk yard!
Therefore it is very hard to believe that various comets on which life independently developed have seeded our planet with new life forms. If that had happened, it would not be true that all life uses the same genetic code. The issue of the genetic code is ignored by the paper by the 33 scientists.
A second problem is that comet collisions would be extremely destructive to earthly life. A comet impact would not be as destructive as an asteroid impact. But a larger comet might have so much kinetic energy that it might cause a mass extinction if it collided with our planet. A scientist says here that a collision with a kilometer-sized comet would probably mean the end of civilization. The chance of life on a comet surviving such an impact does not seem very great. It seems that a comet collision would be likely to destroy far more species than it added to our planet because of an addition of life from the comet.
Does this mean that the idea of extraterrestrial inputs to earthly biology should be discarded and dismissed? Not at all. There is a variation of this idea that gets around the genetic code problem and the collision problem. We can simply hypothesize that rather than being accidental, random inputs from comets, the extraterrestrial inputs were deliberate inputs from intelligent extraterrestrial visitors.
Instead of life-bearing comets arriving at various times in the past, we can imagine life-bearing spaceships arriving here at various times in earth's history. Imagine if the beings populating an extraterrestrial expedition to our planet were to try to speed up the evolution of life on Earth. If such astronauts were to design new organisms to introduce on our planet, they would presumably create designs using the genetic code already used on our planet, rather than using some genetic code coming from their own planet (just as someone visiting Japan from England trying to spread ideas to the Japanese would create books written in Japanese rather than English). And of course, under such a spaceship theory the astronauts would not be smashing their spaceships into our planet, so you avoid the collision destruction problem. So by imagining a purposeful, directed introduction of new life forms into the Earthly biosphere, we have a “life from space” theory that avoids the two big problems of the theory of the 33 scientists.
But such a smarter theory might have been avoided by the 33 scientists on the grounds that it would be hard for a paper advancing such a theory to get published, given the current state of biological academia where there exists ideological restrictions that sometimes seem as great as those in a medieval monastery. For it is a great taboo in colleges and universities for anyone to be talking about purpose, design, and deliberate intent when trying to explain the origin of Earth's living things.
This taboo makes no sense at all. It is the taboo that when discussing the origin of incredibly fine-tuned biological organisms that look just like products of design and purpose, we must never suggest any explanation that involves some purposeful cause. It is the taboo that when discussing biological functionality more impressive than any electronic functionality man has produced, we must always pretend that all these biological innovations were mere accidents. And so our 33 scientists have given us a theory with two giant holes, huge problems that could have been avoided by simply imagining purposeful extraterrestrial visitations rather than purposeless extraterrestrial comet collisions.