Or, A Little Mars & Origins of Life History (and other related thoughts) Before Tackling Today’s Space Exploration Debates, Part IV
Okay, so a couple of posts ago we left Stanley Miller and Harold Urey at the University of Chicago, in 1952, trying to create chemical reactions that would simulate Jupiter’s atmosphere. They were doing this because it was thought that Jupiter’s current atmosphere might closely resemble the atmosphere on early Earth. And the reason they wanted to simulate Earth in its early days was so they might see what conditions were present that led to the emergence of life.
The goal here, remember, was to figure out the origin of life. What kind of environment would be required for life to begin, and what might “spark” life.
Miller and Urey took molecules known to be present in Jupiter’s 1950’s atmosphere and placed them into a closed system. The gas molecules they used were methane (CH4), ammonia (NH3), hydrogen (H2), and water (H2O). Then they ran an electric current through the contained gases, to simulate lightning storms believed to be common in the early days of Earth’s formation. What they had accomplished was to simulate the presumed atmospheric environment of Early Earth. And, remember from our previous discussion with scientist Sherwood Chang, they were looking for some sort of chemical reaction ( a chemical reaction results from something – in this case, gas molecules – reacting with a source of energy – in this case, faked lightening).
So, qué pasó? Well, the scientific journals describe it a bit more scientifically, but I like what Sherwood Chang said to me: “At the end of one week, they fished out what was left in the pot and made the astounding discovery of the presence of amino acids, the building blocks of proteins, and therefore of life!”
At week’s end as much as 10-15% of the carbon was now in the form of organic compounds. Two percent of the carbon had formed some of the amino acids. (source duke.edu) And, also according to Chang, “Three or four of the amino acids they found – in the pot – were the very specific amino acids that all biology uses. Out of a potentially almost limitless number of amino acids that are theoretically possible. Most importantly, The Miller-Urey experiment showed that organic compounds such as amino acids could be made easily under the conditions that scientists believed to be present on Early Earth.
Today most of us don’t realize how big this was. Not just that the scientists “created” the building blocks of life but that they had been able to study something so successfully in a laboratory using a technique of simulation. We take simulations for granted today. But in the 1950s this was huge. And the Miller-Urey experiment resulted in an avalanche of such experiments by other scientists. Simulations of the Early Land, the Early Oceans, the ability of of volcanic events (stuff + energy) or sunlight (energy) and other “stuff” to create organic matter (life), on an on.
As ideas changed about what the Early Earth atmosphere actually consisted of, the simulation ingredients changed. But, eventually these Early Earth chemists managed to produce all the biological amino acids, and lots of other amino acids that are not used in biology.
Scientists at first became very optimistic that they were on the cusp of actually discovering and understanding the origin of life on Earth. In the 1950s many thought that they would have the question of life’s origins wrapped up in a couple of decades. But, in fact, their journey was just beginning.
One of the many interesting things that Sherwood Chang shared with me during our drive between Berkeley and Vallejo came in response to my questioning him about how much he follows scientific progress now that he has turned in his Ames Laboratory garb for a cowboy hat in order to roam and manage his cattle ranch in Northern California.
Sherwood patiently addressed my perhaps over the top enthusiasm about the recent Mars mission and space exploration in general. He explained that a big aha moment for him was the realization of how slow research is. How many years go by, and how little we really learn in each chunk of time. Sherwood played his role in the timeline of human exploration and discovery. Now he is doing something else, cattle ranching. The scientific exploration continues, but the pace is slow and will always be so. It took me a while to “get” what Sherwood was telling me about this.
My aha moment came when I began to read about the controversies that have followed the life creation simulation phase of those enthusiastic 1950s and 1960s scientists. For since that time, controversies have sprung up about the validity of their experiments, and many more, alternate, ideas have been proposed as to how those early amino acid building blocks of life might have “emerged” on Earth. Research takes time. Sometimes results and discoveries are validated, and sometimes they are invalidated – both the validating and the invalidating taking years and years. Sometimes results and discoveries force the asking of many more new questions, the turning in new directions, which, in turn, takes more time. What seems to us in the moment some “great” discovery is usually just a pinpoint on the continuum of exploration – a continuum that will last as long as we do!
So, hats off to Sherwood for the role he played in the search for life on Earth, and happy trails to him on his Northern California ranch.
Next we will look at some of the controversies that succeeded the 1950s and 1960s simulator explorers, and start looking about the theories and research that has followed them. . . .