Looking for life’s origins in the clouds of a moon
by Eric Sorensen | © Washington State University
On the eleventh floor of the Webster Physical Sciences Building, Carol Turse watches over an array of glass tubes, flasks, and electrodes buzzing with 45,000 volts of electricity. Looking out the window, she takes in one of the better views of Pullman and the Palouse hills; looking inside the glasswork of her lab, she sees the atmosphere of Saturn’s largest moon, Titan, and if all goes right, elements of life in the making.
With clouds and a thick, planet-like atmosphere, Titan is unique among the moons in our solar system. It might also be conducive to creating amino acids, the building blocks of life, which is what Turse hopes to see in a few days.
Turse, a doctoral candidate in the School of the Environment’s Laboratory for Astrobiological Investigations, is conducting a variation of the Miller-Urey experiment, the first successful laboratory attempt to test theories about the origin of life. In one flask she is boiling a mix of methane and ammonia, simulating conditions on Titan’s surface.
“I call it the ocean flask,” she says.
As the compounds boil, vapors rise to an “atmosphere flask” where they are exposed to the spark from a Tesla coil. This simulates lightning or some sort of static discharge, which can break the bonds of ammonia or methane and ease the way for more complex organic compounds to form. As the vapors condense, they run through a tube back to the ocean flask. If things go right, a week or so of this activity will produce a primordial soup similar to the “warm little pond” that Charles Darwin once speculated could lead to the chemical creation of a protein around which life would form.
Stanley Miller, a graduate student of the Nobel laureate and then-University of Chicago physical chemist Harold Urey, first conducted the experiment in 1952 after Urey suggested a more primitive earth atmosphere of methane and ammonia may have helped life emerge. Miller built a setup similar to Turse’s and after a week had a yellow-brown solution that contained glycine and several other amino acids.
Miller presented his findings in a seminar attended by Urey and Enrico Fermi, the University of Chicago physicist. At one point Fermi asked Urey if Miller may have indeed demonstrated the way life originated.
“Let me put it this way, Enrico,” replied Urey. “If God didn’t do it this way, he overlooked a good bet.”
Scientists now believe early Earth’s atmosphere was mostly carbon dioxide and nitrogen with little reactive methane and ammonia. Miller could not replicate his results in that milieu, but one of his former students did once he took into account other factors.
Titan also has conditions that challenge a Miller-Urey setup, the chief one being intense cold. Turse couldn’t conveniently replicate –180°C in the lab, but she and her advisor, Dirk Schulze-Makuch, theorize temperatures would warm in the wake of an asteroid or meteorite impact.
Turse, 36, has also reproduced variations of the original Miller-Urey experiment.
“It’s exciting, and it works, but what about other planets and moons?” she says. “That’s what we wanted to do.”
To be sure, the experiment only addresses the origins of life—the first leg of astrobiology’s three-legged stool of origins, evolution, and fate, as in, where life in the universe might be headed.
“It tells us we can make the building blocks of life—amino acids—from non-living, inorganic components,” says Turse. “And that’s great, but that’s not life. People do make the intuitive leap—‘Oh, there are amino acids, there must be life’—but not quite. There’s so much more that you need to have life. At least you have to have some sort of replication, some sort of enclosed cells with a membrane. You don’t have that yet, but at least you have the building blocks, which is important.”
And the synthesis of amino acids raises tantalizing possibilities about not just life on our planet and Titan, but elsewhere in our galaxy and beyond.
“If we could do it that simply with that experiment, there’s no reason you couldn’t do it on other planets, say on Mars, or Titan, or Europa,” says Turse. “And then you can extend that to other planets as well, all these new exoplanets we’re discovering. And I’m sure there’ll be many, many more that we’ll discover as well. And then billions of stars, just in our galaxy. Most of them have planets. The statistical odds are very good of life somewhere else. And it doesn’t have to be complex life.”
After running her apparatus for a week, Turse analyzed the resulting, cloudy soup and found four amino acids—not as many as Miller found, but amino acids nonetheless.
She replicated the experiment and just before turning the equipment off, noticed a bright pink droplet on one of the electrodes, and kept the equipment running. Now she is taking samples of the soup at different times, aiming to see how different compounds are forming and to answer a brand new question for science: Why might a variation of Darwin’s pond be pink?
Comments are temporarily unavailable while we perform some maintenance to reduce spam messages. If you have comments about this article, please send them to us by email: firstname.lastname@example.org