Vials holding the results of a famous chemistry experiment conducted 55 years ago have been discovered in dusty cardboard boxes, and a new analysis of their contents has revealed fresh insights into a big question: the origin of life on earth. In 1953, chemist Stanley Miller tried to duplicate the conditions present on the primordial earth in laboratory flasks, and while some of his results were published to great acclaim, other results were packed away and forgotten–until now.
Miller’s classic experiment involved putting atmospheric components thought to reflect those of the early Earth (ammonia, hydrogen, methane, and water) in a closed system and stimulating that mixture with an electric current to mimic the effects of lightning storms. He generated a small number of biochemically significant compounds, including amino acids, hydroxy acids, and urea, showing that conditions of primitive earth can create the building blocks of life [Ars Technica]. These results generated considerable excitement, but later researchers argued that Miller was wrong about the composition of the young earth’s atmosphere, and the experiment was written off as a novelty.
In the new study, published in Science [subscription required], researchers analyzed vials of material that were produced by a slightly different process that Miller had viewed as a flop; in that process, the gases were also mixed with a jet of steam to replicate conditions around an erupting volcano. Using modern methods to analyze the samples, researchers found they contained a total of 22 amino acids (including some that Miller had never identified in any of his experiments), the most complex mix yet produced by Miller’s method.
Study coauthor Jeffrey Bada, who was a graduate student of Miller’s, says the findings suggest that life could have originated on earth in the fiery and turbulent regions around volcanoes. “The model is that you have these small pockets, volcanic hot spots,” explains Bada, in which a volatile reducing atmosphere, one in which chemicals are more likely to react with one another, may have produced amino acids.
However, theories on the origin of life have moved on since the days of Miller’s original experiments, and have taken decidedly new directions. The discovery of amino acids in meteorites suggested that the building blocks of life came from space, eliminating the need for finding chemical processes that could produce them on Earth. Some scientists have since suggested places like the ocean bottom as most likely to be where the building blocks first came together as a living organism…. “My take on this is you want to consider everything,” Dr. Bada said. “If you can have a homegrown synthesis, perhaps by this mechanism we’ve described here, complemented by stuff falling from space, well, you’ve got a really rich inventory of compounds to work with and set the stage for the origin of life” [The New York Times].
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Image: Ned Shaw, Indiana University
October 22nd, 2008 at 1:48 pm
If you can recreate building blocks of life with two different experiments, imagine how much Nature can do. On every planet, on all the different situations-volcano, particles emissions on the poles, earthquakes, lightnings- you name it.
For me, this experiment proves that life is much more common than we think. And probably that the whole theory that something brought “it” is wrong, because maybe it wasn’t a single lucky even, but a multiplicity of events-from above, from below, from everywhere, that sparkled and spread over, some died away, some evolved and in the end-we had so much life, it simply flourished.
Why it doesn”t happen everywhere? Two possible reasons: A) it requires some basic elements and you can find it where they are present-unlikely since on Earth there are bacteria like everywhere. B) it is all around, we just can’t see it so easily, because it’s based on different building blocks or is on different scale-too big or too small.
In any case, Mars exploration is going on, Europa is also a good candidate for life, so sooner or later, we’ll find out how common life in space is.
June 6th, 2009 at 1:57 am
The implications of Miller’s experiments cannot be fathomed. This maybe among the most significant findings in the modern scientific era. outstanding.