Many people readily accept the idea that Darwin's theory of evolution by natural selection applies on a micro scale, meaning at the level of bacteria and viruses, and maybe even to some extent at the level of species. While they accept these ideas, they reject the idea that Darwin can explain the evolution of life from its most basic forms up to humanity, meaning that while microevolution is real, macroevolution is not. The argument is that supporters of macroevolution have stretched the available data and have "overplayed the hand".
One of the key arguments that skeptics of macroevolution have used is that there simply wasn't enough time to explain the appearance of organisms as complex as bacteria and viruses. The argument hinges on the evidence that the Earth is about 4.5 billion years old, and the amount of time between the formation of Earth and the emergence of bacteria and viruses is therefore too short. Implicit in this is the idea that life must have developed "from scratch" here on Earth. But what if that's a bad assumption?
Two scientists who have called this assumption into question are Alexei Sharov, a staff scientist at the National Institute of Aging, and Richard Gordon, a Theoretical Biologist at the Gulf Specimen Marine Laboratory in Florida. Sharov and Gordon use a novel way to estimate when life first appeared. As a proxy for the complexity of life, they consider the number of base pairs in an organism. More complex organisms have more base pairs than less complex organisms. They observe that number of base pairs of organisms has increased at an exponential rate over time, much like Moore's Law.
In 1965, Gordon Moore looked at the number of transistors on a computer chip and noted that it was doubling every 18 to 24 months. "Curve fitting" just four data points (1962 – 1965), he projected that this exponential growth, referred to as Moore's Law, would continue into the future. In the original paper his projection only went 10 years into the future – to 1975. His ten year projection has taken on a life of its own, and for the past 50 years, his projection has proven accurate. Sharov and Gordon use this as a model and suggest a "reverse Moore's Law". If you look at the historical data for the number of transistors on a chip, you could project backwards to when there were only a handful of chips, all the way back to 1959, the starting point for Moore's original curve fitting graph. For example, if one looks at number of transistors on a chip at various points from 1995 to 2015, then one could "reverse project" that there were only a few transistors on a chip back in the 1950's. The "reverse projection" would be quite accurate.
Sharov and Gordon apply this line of thinking and do a similar "reverse projection" for genetic complexity (see the chart above). They look at the time that various organisms (e.g., prokaryotes, eukaryotes, worms, fish and mammals) emerged, and plotted those dates against the genetic complexity of each type of organism. Eukaryotes and prokaryotes are both organisms with cell membranes, but eukaryotes also have a nucleus. Their "reverse projection" suggests that "genomic complexity of zero, meaning just one base pair of nucleotides", would have occurred approximately 9.75 +/- 2.5 billion years ago. That's well past the date of the Big Bang (approximately 13.8 billion years ago) but also well before the formation of Earth (about 4.5 billion years ago). Even at the outer lower bound, Sharov and Gordon say that life emerged 7.25 billion years ago, still well before our Earth formed.
Thus, Sharov and Moore's proposal could address the objection that many have raised about the appearance of life on Earth. One might argue that life could not realistically have arisen with 500 million years of the formation of Earth, but 5 billion years is more than realistic.
For Sharov and Gordon's theory to be realistic, two key questions need to be answered. First, could life have begun from only one nucleotide base pair? Second, if life began before the formation of Earth, how did early life forms survive travel through interstellar space and arrive intact on Earth?
With respect to the first question, Sharov and Gordon present a theory based upon what they call coenzyme like molecules (CLM's). Their model is hypothetical, but is certainly not out of the question. The core idea is that CLM's could be a realistic precursor to the nucleotides A, C, G, and T that underlie genetics. Sharov and Gordon hypothesize that CLM's existed in a hydrocarbon microspheres. These hydrocarbon microspheres could have created a realistic environment for nucleotides to emerge.
Assuming the original nucleotides emerged about 9.75 billion years plus or minus a couple billion years, somewhere in the universe, how did those nucleotides traverse interstellar space? If that question cannot be adequately answered, whether or not the original nucleotides did emerge at the time hypothesized by Sharov and Gordon, then the idea of life emerging elsewhere in the universe and being transported to Earth is effectively moot. Sharov and Gordon cite the research of L.H. Lambert and others that staphylococcus succinus was extracted from Dominican amber. The spores had been dormant for 25 to 35 million years. At the same time, Sharov and Gordon cite research by Richard Gordon and R.B. Hoover that "remnants of planets from exploded supernovae can carry billions of bacterial spores and maybe even active chemosynthetic bacteria deep beneath the surface." In other words, bacterial spores could have been buried in interstellar material, laying dormant for possibly millions of years, then revived in another world. Sounds somewhat far-fetched, but not necessarily unrealistic.
If Sharov and Gordon are right, then the idea that genetic diversity follows a Moore's Law type of curve isn't far-fetched at all. Moreover, it could overcome the perceived problem that bacteria and viruses could not have formed on Earth because of the short time period from the formation of the Earth until their appearance.
What, then, of the idea that life emerged 9.75 billion years ago, about 5 billion years before Earth formed? The reason this isn't necessarily a crazy is because the universe appears to have as many as 10,000,000,000,000,000,000,000 (that's 10 to the 22nd power) stars like our own. While only a very small fraction of those stars are likely to have had planets with conditions that could have supported the emergence of life, the sheer number of possible candidates makes this a very realistic scenario. Assume, for a moment, that there was only a one in a trillion chance that any particular star could have had a planet capable of supporting life of some sort. Even if that is the case, there would still be approximately 1,000,000,000 (one billion) stars capable of sustaining life. If it was a one in a quadrillion chance, then approximately one million stars have planets orbiting them that are capable of supporting life.
The Big Bang occurred about 13.8 billion years ago. Assuming Sharov and Gordon are correct, then the first life forms appeared about 4 billion years after the Big Bang. Four billion years should have been adequate time for life forms to have emerged.
Assuming this is the case, were the life forms that were transferred to Earth advanced and intelligent? The idea that Earth was seeded by intelligent life (sometimes known as "directed panspermia") is fairly well known. Sharov and Gordon reject the idea that the Earth was seeded by intelligent life. This is because they believe it would have taken at least 10 billion years for intelligent life to have formed. Assuming the Big Bang really did occur 13.75 billion years ago, then even if life formed within a billion years of the Big Bang, at the time of Earth's formation (4.5 billion years ago), then life could only be about 8 billion years in age. Sharov and Gordon contend that it would have taken at least 9 or10 billion years for intelligent life to form (refer back to the chart above), thus it would have been impossible for the Earth to have been seeded by intelligent life.
Non-religious people should have absolutely no problem with Sharov and Gordon's theory, but can the same be said for Christians? I really don't think it should create problems for most Christians.
Young earth creationists (YEC) will definitely have a problem with the theory, but anyone who is a YEC would have problems with any theory suggesting that the Earth, much less the universe, is much older than about 6,000 years. Young earth creationists believe in a literal interpretation of the book of Genesis. On the other hand, old earth creationists and evolutionary creationists (the latter being, like me, those who believe that God created the world using Darwin's evolution by natural selection) should have no problem with the theory.
The Bible says that God created all life, but it doesn't say where or when it happened. The assumption has always been that life was created on Earth, but it doesn't specifically make that statement. For most of history, most everyone assumed that life was created on Earth, but no one was aware of the sheer size and age of the universe, and no one was aware of the genetic curve calculated by Sharov and Gordon, suggesting that life began about 9.75 billion years ago.
At this point, Sharov and Gordon's analysis doesn't prove or disprove anything, but I believe it is useful because it helps reduce constraints on our thinking about how life emerged. For the longest time, we've constrained ourselves to the assumption that life had to have begun on Earth, not somewhere else. The available data have not always
fit this model well. Eliminating the constraint creates the possibility of other alternatives. At the same time, it also doesn't provide any more evidence that life spontaneously emerged, the claim of many atheists and non-theists.
If anything, the argument made by Sharov and Gordon should be encouraging for Christians who believe that Darwin's theory of evolution by natural selection is correct. This is because it provides a way to overcome the objection that life could not have emerged on Earth according to Darwin's theory because of the relatively short time between the formation of the Earth and the emergence of life.