Fwd: [evol-psych] Neuroscientist finds signature of life on Mars in decades-old data

From: Robin Hanson (rhanson@gmu.edu)
Date: Mon Jul 30 2001 - 11:25:10 MDT

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>Subject: [evol-psych] Neuroscientist finds signature of life on Mars in
>decades-old data
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>Public release date: 27-Jul-2001
>University of Southern California
>USC neuroscientist finds signature of life on Mars in decades-old data
>San Diego, July 29, 2001 ­Experiments done more than two decades ago on
>soil collected by the Viking Landers 1 and 2 provided evidence that life might
>exist on the Red Planet, says Joseph Miller, Ph.D., associate professor in the
>Department of Cell and Neurobiology at the Keck School of Medicine of the
>University of Southern California.
>Miller recently did a re-analysis of data collected by the landers, and found
>that something in the collected soil was apparently metabolizing nutrients—and
>doing so with a distinct biological rhythm that, he says, can only be found in
>a living cell. Miller presented his findings today at an astrobiology
>held during the International Society for Optical Engineering’s 46th Annual
>In August and September of 1975, the Viking spacecraft were launched from Cape
>Canaveral. After travelling for nearly a year, each reached the atmosphere of
>Mars and the landers were deployed to the planet’s surface. Once there, they
>performed a series of experiments—including one in which a robotic arm scooped
>up samples of soil and deposited them in petri dishes, along with a drop of a
>nutrient solution that had been labeled with radioactive carbon. The idea,
>explains Miller, was that if there were any living organisms in the sample,
>they would take up the carbon-labeled nutrients and process them, eventually
>releasing the radioactive carbon in a gas form. A radiation detector was
>set up
>near the covered dish, connected to it by a tube through which any released
>gases would travel.
>And travel they did, says Miller. When the data were collected, the original
>researchers involved with the Viking expedition—Patricia Straat and Gilbert
>Levin—found definite evidence of gas release. It seemed they had indeed found
>life on Mars—but other scientists suggested that the release might be better
>explained as the result of chemical reactions with highly reactive compounds
>like superoxides and peroxides. Unable to prove that the gas was definitely
>being released by living organisms, the NASA scientists let the matter drop.
>And so those tantalizing data sat, more or less undisturbed, until 1999.
>Miller, who had worked for NASA in the early 1980s, studying the effects of
>zero gravity on circadian rhythms in squirrel monkeys, began writing a
>to NASA to do biology on future Mars expeditions. It was then that he saw a
>figure in a geophysical journal taken from the data from the Viking Lander 2
>experiment—a figure that showed highly periodic gas release in Levin and
>’s experiment.
>Although the science of biological clocks hadn’t been advanced enough at the
>time of the Viking experiments to help the researchers make their case, it had
>come a long way in the intervening years. And Miller immediately knew he had
>something potentially exciting on his hands.
>"I immediately got interested," says Miller. "So I asked NASA if I could look
>at the data." It took a number of calls—and a good four months—to uncover what
>Miller was looking for. And when NASA found it, there was a problem. "The data
>were on magnetic tapes, and written in a format so old that the
>programmers who
>knew it had died," Miller said.
>Eventually, NASA was able to recover the data from printouts, luckily
>by Levin and Straat—and so, Miller was able to pore over the numbers. There
>were a lot of them—in fact, their analysis is still underway. But even after
>having crunched just 30 percent of the experiment’s data, Miller was able to
>find something remarkable—something, he says, that went unremarked-upon in the
>original papers. "The signal itself not only had a circadian rhythm," declares
>Miller, "but it had a precise circadian rhythm of 24.66 hours—which is
>particularly significant, because it’s the length of a Martian day."
>More specifically, says Miller, the fluctuations in gas emissions seem to be
>entrained to a 2 degrees C fluctuation inside the lander, which in turn
>reflected not-quite-total shielding from the 50 degrees C fluctuation in
>temperature that occurs daily on the surface of Mars. Temperature-entrained
>circadian rhythms, even to a mere 2-degree C fluctuation, have been observed
>repeatedly on earth.
>As for the original concerns of the dubious chemists, who thought the same
>of signal could simply be coming from highly reactive, non-organic
>compounds in
>the soil, Miller says such a scenario would be almost impossible to imagine.
>"For one thing," he explains, "there has since been research that shows that
>superoxides exposed to an aqueous solution—like the nutrient solution in the
>experiment—will quickly be destroyed. And yet, the circadian rhythms from the
>Martian soil persisted for nine straight weeks."
>"There is no reason for a purely chemical reaction to be so strongly
>synchronized to such a small temperature fluctuation," he adds. "We think that
>in conjunction with the strong indications from Mars Observer images that show
>water flowed on the surface in the recent past, a lot of the necessary
>characteristics of life are there. I think back in 1976, the Viking
>had an excellent reason to believe they’d discovered life; I’d say it was a
>good 75 percent certain. Now, with this discovery, I’d say it’s over 90
>percent. And I think there are a lot of biologists who would agree with me."
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Robin Hanson rhanson@gmu.edu http://hanson.gmu.edu
Asst. Prof. Economics, George Mason University
MSN 1D3, Carow Hall, Fairfax VA 22030-4444
703-993-2326 FAX: 703-993-2323

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