Latest Attempt to Explain Homochirality Underscores the Problem

Finding that some stars emit circularly polarized light will not help explain why life uses only left-handed amino acids.

Periodically, another attempt is made to explain the one-handedness of life’s amino acids.  The problem for materialists, explained in our online book chapter 3, is that only 100%-pure one-handed proteins will work, but the probability of getting pure one-handedness (“homochirality”) by chance is vanishingly small (chapter 4).  The latest article addressing this problem on PhysOrg admits it:

Life on Earth is made of “left-handed amino acids (L-amino acids)”. The question of why organisms on Earth consist of L-amino acids instead of D-amino acids or consist of D-sugar instead of L-sugar is still an unresolved riddle. In other words, a major mystery of life on Earth is that organisms are exclusively made up of left-handed amino acids. Therefore, the effort to solve this problem is one of the biggest in research into the origins of life, a subject that remains enveloped in mystery.

The homochirality problem is enormous: “Origin-of-life theories often ignore the homochirality problem, even though the question is critical to the origin of life,” the article states.  All known physical processes lead to mixed-handed (“racemic”) collections.  Since the two forms behave the same chemically and thermodynamically, how can they be separated?  Only life seems capable of producing pure one-handed sets.

Previous attempts have tried to discover physical factors that might lead to a preference for one hand over the other (“enantiomeric excess”), but they have only achieved differences of a few percent.  PhysOrg explained the leading multi-step hypothesis for separating the hands: (1) Find stellar sources of circularly polarized light that might preferentially destroy one hand or convert it to the other; (2) Have the amino acids delivered to Earth via meteorites; (3) Purify the one hand further in shallow basins undergoing cyclic periods of wetting and drying.

Now, astronomers at the National Observatory of Japan have detected the highest ever circular polarization excess from a star: 22%.     Their paper was published in The Astrophysical Journal Letters.  This has “implications for the origin of homochirality,” the PhysOrg headline reads. NASA’s Astrobiology Magazine reproduced the press release verbatim, categorizing it as a “Hot topic,” headlining it, “Star- and Planet-Forming Regions May Hold Key to Life’s Chirality.”  If so, the implications are pretty weak, and the key hard to find, since polarization only addresses half of the first step in the chain.  It is not known how effective circularly polarized light is in causing changes to amino acids.  The finding also requires that most of life’s amino acids were sent to Earth on meteorites – a controversial claim.  Even then, the enantiomeric excess would likely be small, and exist only in tiny locales (shallow pools) that reduce the lab space for life’s origin.  But unless a growing protein chain is 100% pure with one hand, it won’t work.  A generous scenario with 22% excess (assuming the amino acid population trends with the polarized light excess) is far too small to help, even if origin-of-life researchers could figure out a way for the amino acids to link up naturally (they prefer to separate in water).

Homochirality is not the only mystery.  “The history of star and planet formation and the origin of life are still a mystery,” too, the article confessed.

Could the pure one-handedness in life be bona fide evidence for intelligent design?  Louis Pasteur, the man who discovered homochirality, thought so.  For more than a century this problem has baffled materialists.  They’ve been trying to relegate this to a god-of-the-gaps argument for too long.  One can’t keep using that excuse forever.  If the gap keeps getting wider, or if the evidence creates a positive argument for design, there comes a time to turn that excuse around and accuse materialists of materialism-of-the-gaps, the faith that somehow, sometime, a solution will emerge.  But why must materialism be the default position?  Scientists cannot live in the land of mystery for decades and still call it science.  If the evidence points to design, so be it.