Applying a maxim from computer science to biology raises the intriguing possibility that life existed before Earth did and may have originated outside our solar system, scientists say.
Moore's Law is the observation that computers increase exponentially in complexity, at a rate of about double the transistors per integrated circuit every two years. If you apply Moore's Law to just the last few years' rate of computational complexity and work backward, you'll get back to the 1960s, when the first microchip was, indeed, invented.
Now, two geneticists have applied Moore's Law to the rate at which life on Earth grows in complexity — and the results suggest organic life first came into existence long before Earth itself.
Staff Scientist Alexei Sharov of the National Institute on Aging in Baltimore, and Theoretical Biologist Richard Gordon of the Gulf Specimen Marine Laboratory in Florida, took Moore's Law, replaced the transistors with nucleotides — the building blocks of DNA and RNA — and the circuits with genetic material, and did the math.
The results suggest life first appeared about 10 billion years ago, far older than the Earth's projected age of 4.5 billion years.
So even if it's mathematically possible for life to have existed before Earth did, is it physically possible? Again, Sharov and Gordon said yes, it is. As our solar system was forming, pre-existing bacterialike organisms, or even simple nucleotides from an older part of the galaxy, could have reached Earth by hitching an interstellar ride on comets, asteroids or other inorganic space debris — a theoretical process called panspermia.
The scientists’ calculations are not scientific proof that life predates Earth — there's no way of knowing for sure that organic complexity increased at a steady rate at any point in the universe's history. Call it a thought exercise or an essay, rather than a theory, Sharov said.
"There are lots of hypothetical elements to [our argument]… but to make a wider view, you need some hypothetical elements," Sharov told TechNewsDaily.
Sharov and Gordon's idea raises other intriguing possibilities. For one, "life before earth" debunks the long-held science-fiction trope of the scientifically advanced alien species. If genetic complexity progresses at a steady rate, then the social and scientific development of any other alien life form in the Milky Way galaxy would be roughly equivalent to those of humans.
Sharov and Gordon's study draws a theoretical and practical parallel between the origin of life and the relationship between life and knowledge. Human evolution doesn’t just occur in the genome; it occurs epigenetically, or within the mind, as technology, language and cultural memory all become more complex. "The functional complexity of organisms [is] encoded partially in the heritable genome and partially in the perishable mind," they explain in the paper.
By applying Moore's Law — a theory originally devised to explain technological development — to life, the geneticists aren’t simplifying evolution; they’re acknowledging its extraordinary complexity, they say.
Although some may be skeptical of Sharov and Gordon's findings, the scientists stand by their conclusions. "Contamination with bacterial spores from space appears the most plausible hypothesis that explains the early appearance of life on Earth," they argue in the paper, which is published online in the preprint journal Arxiv.
Sharov said that if he had to bet on it, he’d say "it's 99 percent true that life started before Earth — but we should leave 1 percent for some wild chance that we haven’t accounted for."
The full report is available on Cornell University Library's online archives.