Primordial Soup: Interview with Stanley Miller

An anonymous reader writes "Stanley Miller's classic 'primordial soup' experiments showed that 13 of the 21 amino acids necessary for life could be made in a glass flask. For its fifty-year commemoration, Miller is interviewed today and reflects on what Carl Sagan called 'the single most significant step in convincing many scientists that life is likely to be abundant in the cosmos.'"

Comments

High School Biology Class

[Schezar]

For two years, I bugged my Biology teachers to let my try the Miller experiment with the school's equipment. (Of course, I was the same one who wanted them to let me make a gauss rifle, a betatron, and potato gun...)

I remember being fascinated when I first heard of the experiment. It seemed so 'important,' despite the fact that they brushed right over it and no one else in my classes understood or cared.

Of course, now I'm in college, and I can try all of these things with my own equipment.

Re:Carl Sagan was missing Billions and Billions of

[dubstop]

You're whining that the odds are too big, but it's guys like Stanley Miller that are trying to figure out exactly how big those odds are.

You might want to actually provide some facts as to why Carl Sagan was wrong, rather than make an ad hominem attack. Most truly academic scientists generally take a bit more convincing than just being told that, "The guy was an asshole, so he must be wrong."

Re:Carl Sagan was missing Billions and Billions of

[Planesdragon]

So, the chances are actually incalculable. Lottery = your chances in getting picked out the pool may be one in a million, but your chances of picking the right number on the right day and being that one in a million are impossible odds. Then you have the odds of actually claiming your prize and meeting the eligibility/legitimacy of the prize.

Odd. I could swear that there are people who've actually won the lottery... a couple hundred in America, I wager, which puts them at just about 1 in a million. ;)

Statistic impossibilities mean "don't plan on it happening to you," not "it'll never happen to anyone."

Miller is defunct

[searleb]

For more information on Miller and prebiotic Earth, here is a quotation from an Angew. Chem. review article by Kay Severin called Hot Stones or Cold Soup? New Investigations on the Endogenous Origin of Organic Compounds on Earth (Angew. Chem. Int. Ed 2000, 39, No. 20). It pretty much sums up the Miller reactions, why they're wrong, and what people think now:

"The most famous experiment ... was carried out almost fifty years ago by Stanley L. Miller, at that time a PhD student in the group of Harold Urey in Chicago. Miller was able to show that electric discharges in an atmosphere of methane, ammonia, hydrogen, and water led to the formation of significant amounts of various amino acids. Experiments of this kind were repeated in numerous variants. If reducing gases were employed mixtures of organic compounds of low molecular weight could be detected in many cases. This has led to the popular idea that the primordial ocean resembled a nutritious soup.

"But the possibility that earth once had a reducing atmosphere is questioned. A well known argument against it is the high photolability of methane and ammonia. Because a shielding layer of ozone was missing a high concentration of these gases is believed to be unlikely. Furthermore, several other results point to a neutral atmosphere of CO2 and N2. Given the fact that the atmosphere was based on an unproductive mixture of CO2 and N2 the nutritional value of the primordial ocean drops significantly.

"An alternative scenario has been propagated for several years by [Gunter] Wachterhauser. Instead of a primordial soup he favors hot minerals as the place where organic molecules were initially built as life subsequently emerged. Especially sulfur-containing minerals like pyrite are proposed to have acted as an energy source and catalyst both under the extreme conditions found in hydrothermal or volcanic vents."

Basically, primordial soup syntheses (like Miller's reactions) are out and hot rock syntheses are in. These hot rock procedures have much much much lower yields, but people are slowly figuring out how to build amino acids through them. For instance, people, headed by Wachterhauser, have figured out how to carbon fixate (condense) carbon monoxide and carbon dioxide into organic building blocks for amino acids. For instance, in early 2000, Chen and Bahnemann were able to convert CO2 and water to small organics (acetaldehyde, ethanol, acetic acid) at high pressures and temperatures. Similarly, people have figured out how to take amino acids and convert them into peptides under high temperature and pressure situations.

However, to date no one has been able to actually make an amino acid through these techniques. As a result, the proof that amino acids were delivered by comets or meteorites (true fact, this is not an x-file) and now space dust, becomes much more appealing. Once the building blocks arrived on Earth, these hot rock syntheses could have taken over.