A commenter left this link on an unrelated post. Since the commenter has, in the past, tried to support several unscientific positions, I assume he or she thought that the experiment demonstrated the plausibility of abiogenesis, the the idea that life might have emerged through a series of incredibly unlikely interactions between nonliving chemicals. Of course, such an idea contradicts everything we know about the study of life, since all life we have ever studied comes from other living things. I have written several articles (here, here, here, here, here, and here) that demonstrate how the data speak against abiogenesis, but those who want to ignore the scientific evidence desperately hope for some special time in the past when all our current evidence doesn’t apply and life could actually spring from nonliving chemicals.
One of the many, many problems associated with any naturalistic origin-of-life scenario is that of stereoisomerism. As I explain here, there are certain biological molecules that can be formed in two different ways. They have the same chemical formula and form mirror images of each other. However, these mirror images are not identical. Think about your hands. When you hold them palms together, they are mirror images of one another. However, no matter how you tilt or turn it, you cannot make your left hand look identical to your right hand. If you put the palm of one hand on the back of the other hand, for example, one hand’s thumb will be where the other hand’s pinky finger is. So while your hands are mirror images, they are not identical. There are many biological molecules that are like that, and we call them chiral molecules. The two mirror images that are formed by a chiral molecule are called enantiomers.
All origin-of-life scenarios start with simple molecules that do not form enantiomers. We call these achiral molecules, since they cannot form two mirror images that are different from one another. This is a problem, because in the lab, when achiral molecules react to form a chiral molecule, an equal amount of each enantiomer is formed. As a result, you end up with a mixture that is 50% one enantiomer and 50% the other enantiomer. We call this a racemic mixture. The problem is that life isn’t like that. In most chiral molecules of life, only one of the enantiomers is used. We call this an enantiopure compound, since it is purely one enantiomer, without any of the other. So any origin-of-life scenario has to figure out a way of producing just one enantiomer, or it has to figure out a way to get rid of the other enantiomer once it has formed.
This is a major problem, of course, and the link that the commenter left claims that a “plausible” solution to this problem has been found. Of course, when you look at the actual paper you find that the process is anything but plausible in an origin-of-life scenario.
Continue reading “When You’re Desperate, Anything Is Plausible”