Why the Discovery of Nucleobases Bases in Meteorites Doesn't Mater

Recent discoveries show that certain meteorites contain all five of the standard DNA and RNA nucleobases: adenine, guanine, cytosine, thymine, and uracil. 

While adenine and guanine were found in meteorites decades ago, the detection of cytosine and thymine in a meteorite sample in 2022 confirmed the presence of all five. Some believe it supports the theory of panspermia, which posits that the fundamental building blocks of life could have originated in space and been delivered to early Earth. The discovery suggests that the raw materials for genetic information, which are essential for all known life, are not unique to Earth but are common in the cosmos. These findings strengthen the argument that the universe is ripe with the chemical ingredients necessary for life to emerge. 

The synthesis of nucleotides from base pairs through plausible synthetic mechanisms is challenging. For a simple nucleotide to form, a nucleobase must react with a five-carbon sugar (ribose or deoxyribose) and a phosphate group. This reaction, known as a glycosidic bond formation, is a dehydration synthesis, where a water molecule is removed. In an aqueous environment, which is what we would expect in a prebiotic soup, this reaction is thermodynamically extremely unfavorable. There would have to be a series of improbable and inefficient reactions. For instance, the formamide pathway, where nucleobases and sugars might form in a non-aqueous solution, could be a possible, though still highly improbable, synthetic mechanism. Another mechanism involves using cyanamide, a molecule that has been found in some meteorites, as a catalyst to facilitate the formation of the glycosidic bond.

The improbable synthesis of chiral nucleotides poses another significant challenge. 

 Chiral molecules exist as two mirror image forms, a property called chirality. A good analogy is the right and left hand. Biological systems, however, predominantly use only one form, or enantiomer, of each chiral molecule. For example, all life on Earth uses D-ribose for RNA and D-deoxyribose for DNA, and L-amino acids for proteins. A prebiotic synthesis would produce a racemic mixture, which is an equal amount of both the D and L forms. The spontaneous emergence of a single-handed, or homochiral, system from this mixture is highly improbable. This process would require a mechanism to select for or amplify one enantiomer over the other, which is a major hurdle in abiogenesis.

Even if every atom in the universe were a single, correctly synthesized chiral nucleotide, the odds of a simple gene of 500 nucleotides forming by chance would be 4^500. This is because there are four possible nucleotides (A, C, G, U, T) at each of the 500 positions. The number 4^500 is an unimaginably large number, far greater than the number of atoms in the universe and more than the number of seconds that have passed since the Big Bang (10^17 seconds). The sheer magnitude of this number underscores the statistical impossibility of a functional gene or a random sequence of this length forming spontaneously by chance alone within the time frame of the universe's existence. It's a key argument against the idea that life emerged purely by random chance.

Its yet another strong argument for intelligent design.