Series - "Icons of Evolution, The Miller-Urey Experiment" (Pt. 2)

Last week we started looking at the Icons Evolution, the 10 most so called "proofs" that evolution is true. The first one we looked at was the Miller-Urey experiment. We looked at what exactly the experiment was, who made it and how it influenced textbooks. Today we will be looking at how this experiment is not scientific.

Our atmosphere is about 21% oxygen. Oxygen is one of the most important things needed for life, because without it we would die, but with it life’s building blocks could not have formed in an atmosphere where oxygen is present. An electric spark in a closed container of swamp gas (methane) might produce some interesting organic molecules, but if even a little oxygen is present the spark will cause an explosion. Because oxygen can destroy many organic molecules, chemists often have to remove oxygen and use closed containers when they store organic chemicals in labs. But before the origin of life, when there were neither chemists nor laboratories, the chemical building blocks of life could have formed only in a natural environment lacking oxygen. According to Oparin and Haldane, that environment was the Earth's primitive atmosphere.

Some scientists believed that the Earth originally formed from a condensing cloud of interstellar dust and gas, so it was reasonable to suppose that the original atmosphere was similar to interstellar gases, which was mainly hydrogen. In 1952, Nobel Prize-winning chemist Harold Urey concluded that the early atmosphere consisted primarily of hydrogen, methane, ammonia and water vapor just as Oparin and Haldane had speculated. Miller assembled a closed glass apparatus in Urey's laboratory, pumped out the air, and replaced it with methane, ammonia, hydrogen and water. (If he hadn't removed the air, his next step might have been his last.) He then heated the water and circulated the gases past a high-voltage electric spark to simulate lightning.

Did the primitive atmosphere really lack oxygen?

Urey assumed that the Earth's original atmosphere had the same composition as interstellar gas clouds. In 1952, however (the same year Urey published this view), University of Chicago geochemist Harrison Brown noted that the abundance of the rare gases neon, argon, krypton, and xenon in the Earth's atmosphere was at least a million times lower than the cosmic average, and concluded that the Earth must have lost its original atmosphere (if it ever had one) very soon after its formation.

In the 1960s Princeton University geochemist Heinrich Holland and Carnegie Institution geophysicist Philip Abelson independently concluded that the earth did not get it’s primitive atmosphere from  interstellar gas clouds, but from gases released by the Earth's own volcanoes. They saw no reason to believe that ancient volcanoes were different from modern ones, which release primarily water vapor, carbon dioxide, nitrogen, and trace amounts of hydrogen. Since hydrogen is so light, Earth's gravity would have been unable to hold it, and (like the rare gases) it would quickly have escaped into space. But if the principal ingredient of the primitive atmosphere was water vapor, the atmosphere must also have contained some oxygen. Atmospheric scientists know that ultraviolet rays from sunlight cause dissociation of water vapor in the upper atmosphere. This process, called "photodissociation," splits water molecules into hydrogen and oxygen. The hydrogen escapes into space, leaving the oxygen behind in the atmosphere. Nevertheless, photodissociation would have generated small amounts of oxygen even before the advent of photosynthesis. The question is, how much?

Theoretical models implied some primitive oxygen, but no one knew how much. Evidence from the rocks was inconclusive, and the biochemical evidence seemed to point to significant levels of oxygen produced by photodissociation. The controversy raged from the 1960s until the early 1980s, when it faded from view.

The Miller-Urey experiment succeeded in synthesizing organic molecules, but the question was not whether organic molecules could be synthesized in the laboratory. Of course they could, and they had been for years.

The success of the Miller-Urey experiment doesn't prove that the entire primitive atmosphere lacked oxygen any more than the success of modern organic chemistry proves that the modern atmosphere lacks oxygen.

The March 1998 issue of National Geographic carries a photo of Miller standing next to his experimental apparatus. The caption reads: "Approximating conditions on the early Earth in a 1952 experiment, Stanley Miller-now at the University of California at San Diego-produced amino acids. `Once you get the equipment together it's very simple,' he says."
Several pages later, the National Geographic article explains: "Many scientists now suspect that the early atmosphere was different from what Miller first supposed." But a picture is worth a thousand words-especially when its caption is misleading and the truth is buried deep in the article.
Many biology textbooks use the same misleading approach. Like the National Geographic article, the Miller-Levine textbook buries a disclaimer in the text: "Miller's original guesses about the Earth's early atmosphere were probably incorrect,"

A picture is worth a thousand words, sometimes it comes with dollar signs for the artists. How many times have we been misled by a picture in our text books of what an artist thinks it may have looked like? We see a man standing next to his experiment and just because he is a scientist it must be true. Even though this experiment has been proven wrong decades ago, it is still in text books, television shows and quoted as being true. Don't be misled.

Research the evidence, find the truth and remember..... Have an Intelligent Faith!!

- Nelis