The basic elements of life can not only, but have formed, spontaneously, under the right conditions. This is called spontaneous generation, or abiogenesis. Obviously, many of the details remain hidden from us, and we just don’t know exactly how it happened. Or how often it could happen.
The religions of the world have different ideas of how life came about, of course, and they call on the magical hands of various supernatural deities to explain everything. But these explanations, although they are colorful tales, leave many of us dissatisfied.
“How did life come about?” This is one of life’s most embarrassing questions and one that science continually struggles to find the answer to.
Tomonori Totani is a scientist who finds this question embarrassing. Totani is a professor of astronomy at the University of Tokyo. He wrote a new article entitled “Emergence of life in an inflationary universe”(Emergence of life in an inflationary universe). It is published in Nature Scientific Reports.
Totani’s work relies heavily on some concepts. The first is the vast age and size of the Universe, how it is inflated over time and the probability of events occurring. The second is RNA; specifically, how long does a nucleotide chain need to have to “wait for self-replicating activity”, as the article says.
Totani’s work, like almost all work on abiogenesis, analyzes the basic components of life on Earth: RNA or ribonucleic acid. DNA sets the rules for how individual life forms take shape, but DNA is much more complex than RNA.
In turn, RNA is even more complex, by orders of magnitude, than the chemicals and crude molecules found in space or on the surface of a planet or moon. But its simplicity compared to DNA increases the likelihood of occurrence due to abiogenesis.
There is also a theory in evolution that says that although DNA carries the instructions for building an organism, it is RNA that regulates the transcription of DNA sequences. This is called RNA-based evolution and says that RNA is subject to Darwinian natural selection and is also hereditary. That is one of the reasons behind RNA x DNA analysis.
RNA is a chain of chemicals known as nucleotides. Some research shows that a nucleotide chain needs to be at least 40 to 100 nucleotides long before self-replicating behavior called life can exist.
Over time, enough nucleotides can form a chain to meet this length requirement. But the question is: has there ever been enough time in the life of the Universe? Well, we’re here, so the answer must be yes, right?
But wait. According to a press release announcing this new article, “… current estimates suggest that the magic number of 40 to 100 nucleotides should not be possible in the volume of space that we consider the universe to be observable”.
The key here is the term “observable universe”.
Totani says:
However, there is more to the universe than is observable. In contemporary cosmology, it is agreed that the universe has gone through a period of rapid inflation, producing a vast region of expansion beyond the horizon that we can observe directly. The inclusion of this greater volume in abiogenesis models greatly increases the chances of life occurring.
Our universe emerged during the big Bang, a single inflation event. According to Totani’s article, our Universe “probably includes more than 10 ^ 100 stars similar to the Sun”, while the observable Universe contains only about 10 sextillion (10 ^ 22) stars.
We know that life has occurred at least once, so it is not out of the question that abiogenesis has occurred at least once more, even if the chances are infinitesimally small.
According to statistics, the amount of matter in the observable Universe should only be able to produce RNA 20 nucleotides in length, well below the number 40 to 100. But, due to rapid inflation, much of the Universe is unobservable. It is simply too far for the light emitted from the big Bang reach us.
When cosmologists add the number of stars in the observable Universe to the number of stars in the unobservable Universe, the resulting number is 10 ^ 100 stars similar to the Sun. This means that there is much more matter at stake, and the abiogenic creation of chains of Long enough RNA is not only possible, but likely or even inevitable.
In his work, Professor Totani affirms the basic relationship under investigation:
Here, a quantitative relationship is derived between the minimum length of RNA / min needed to be the first biological polymer and the size of the universe needed to wait for the formation of such a long and active RNA by randomly adding monomers.
Are you getting confused? Here’s a hopefully more understandable summary.
The Universe is larger than its observable portion and probably contains 10 ^ 100 stars similar to the Sun. In order for the probability of abiotic RNA creation on an Earth-like planet to be equal to 1, or unit, the minimum nucleotide length must be less than about 20 nucleotides, which is much less than the initially stated minimum of 40 nucleotides.
But scientists don’t think that RNA with only 20 nucleotides can be self-replicating, at least not from our perspective as observers of terrestrial life. As Totani says in his article:
Therefore, if extraterrestrial organisms of a different origin from Earth are discovered in the future, this would imply an unknown mechanism at work to polymerize nucleotides much more quickly than random statistical processes.
What would that process be?
Nobody knows, but this is probably an inflection point where people of faith can shout and say, “God, of course.”
Totani’s work never provided an answer. But, like many scientific works, it helps to refine the issue and invites others to study it.
Totani said:
Like many in this field of research, I am driven by curiosity and big questions.
Combining my recent research on RNA chemistry with my long history of cosmology leads me to realize that there is a plausible way for the universe to go from an abiotic (lifeless) state to a biotic state. It is an exciting thought and I hope that research can build on that to discover the origins of life.
