NASA: Mars Soil Could Support Extreme Life Forms, Maybe
Martian soil may be less Earth-like than previously thought, but that doesn't mean it can't support life, NASA scientists said today.
After rumors that NASA was about to announce an unexpected discovery about the "potential for life" on Mars surfaced on the Internet, the agency decided to hold a press conference to reveal their new data.
What the Lander's wet chemistry lab appears to have found is some type of perchlorate, a molecule composed of chlorine and oxygen.
While the finding was unexpected, the scientists said that the team's consensus was that it neither increased nor decreased the potential for life on Mars.
Then, in a live teleconference with reporters, the mission's lead investigator, Peter Smith, said, "It probably comes down on the positive side."
Phoenix Lander's mission was to assess the habitability of the northern polar region of Mars. The mission has confirmed the presence of water, but has not found evidence of organic molecules, the building blocks for life. Outside of visual inspection with its on-board microscope, the lander does not have the means to detect life.
While perchlorate could have little impact on the ability of microorganisms to survive on the planet, confirming the molecule's presence in Martian soil could, as mission scientist Michael Hecht put it, "open a new chapter" in Mars science.
In particular, perchlorate's high solubility could help scientists deduce what happened to the water they believe once flowed freely on the surface of Mars.
"Perchlorates will tell us quite a bit about the history of water," said Richard Quinn, a Phoenix and NASA Ames researcher. "Not just at the Phoenix site but in other parts of Mars."
The scientists said they held the press conference earlier than intended to quell rumors about their findings. As a result, they did not follow all of the standard procedures.
While the researchers believe they have firm evidence that the wet chemistry lab detected perchlorate, they have not been able to confirm the presence of the molecule with a separate instrument, the thermal analyzer.
Even if confirmed, the significance or importance of the discovery is far from clear. For example, there are a variety of types of perchlorates with different properties and the researchers are not sure which perchlorates were in their sample. Hecht detailed one intriguing possibility -- magnesium perchlorate -- specifically.
"It's a very effective agent for soaking up water, like a silica gel packet," Hecht said. "When it's very wet, it forms a sticky substance at very low temperature like antifreeze."
But all the researchers cautioned against speculating too much about what the presence of perchlorate might mean until they've had time to clarify and confirm the discovery.
One place they're digging for information on perchlorates is the Atacama desert in Chile, one of the driest places on Earth and a commonly used analog for Mars research. In that location, some microbes use the molecule as an energy source.
"There are microbes that live on the energy contained by this oxidant," Smith, the lead investigator, said. "In itself, it is neither good nor bad for life."
10:59 AM: Waiting on hold for the call to begin. Nice classical music. Relaxing.
11:07 AM: NASA PR person, Duane Brown, says, "There were reports over the weekend that indicated that NASA had a major discovery that NASA was withholding from the public... Today's teleconference is going to set the record straight." Up first to speak is Mike Hecht, chief scientist for the overall Mars Exploration program. Then, we've got Peter Smith, a chemistry lab scientist, and then a thermal analyzer scientist.
11:12 AM: Peter Smith, the mission's lead investigator, says that "we have substantial evidence that our soil samples has perchlorates." On Earth, the substances are found in the Atacama desert, a common analog for Mars study. Smith says, "They are highly stable and do not destroy life under normal conditions. In fact, there are microbes that live on the energy contained by this oxidant. In itself, it is neither good nor bad for life." (Emphasis added.)
11:14 AM: There is a slight chance that the perchlorate was brought to Mars by Phoenix, but that seems unlikely.
11:18 AM: Mike Hecht says that the evidence is solid for perchlorate. They've reproduced the sensor signal they got on Mars, in the lab on Earth, and eliminated likely explanations outside perchlorate.
11:20 AM: Mike Hecht: "We don't know what mixture of perchlorate salts we have in our solution. Sodium perchlorate, ammonium perchlorate, magnesium perchlorate. Let's take magnesium perchlorate. It's a very effective agent for soaking up water, like silica gel packet... When it's very wet, it forms a sticky substance at very low temperature like antifreeze. We've only begun to think about what this might mean, but they could keep a lot of graduate students busy for a long time." Fascinating!
11:23 AM: Peter Smith says of perchlorate salts, "It's a stable molecule and it doesn't preclude life on Earth. In fact, it could be an energy source."
11:24 AM: The thermal analyzer scientist, Bill Boynton says that his TEGA instrument has not been able to confirm the discovery. That could happen if they could detect chlorine gas, which could be produced by heating some types of perchlorates.
11:28 AM: Richard Quinn, in response to a question from CNN says, "There were some initial reports in the the scientific literature that the Atacama was very Mars like. They couldn't find organics or culture microbes. But as research continued, we found organics... and then when we looked closer, we found microbes. So it turned around. Microbes can exist quite happily in oxidizing conditions and the story could be the same for Mars. We don't know for sure."
11:34 AM: Michael Hecht says that the Phoenix samples could be similar to the soil on the rest of Mars, but it's unclear how generalizable the lander site results are.
11:40 AM: The next step in the investigation will be trying to confirm the wet chemistry lab's results with other instruments on the lander, Hecht says.
11:45 AM: Question--why didn't other probes find perchlorates? Richard Quinn responds, "The other probes had different focuses than the MECA (wet chem.), which is looking for soluble salt, and perchlorate is a very soluble salt." Hecht called the discovery "a new chapter" in Mars science.
11:50 AM: Quinn makes a good point about why perchlorates are important, aside from habitability. "Because perchlorates are chemically inert, they move through the soil very quickly in the presence of water. This ties back to Mars. Perchlorates will tell us quite a bit about the history of water. Not just at the Phoenix site but in other parts of Mars."
12:00 PM: The team agrees that the discovery of perchlorate does not impact the habitability of Mars up or down.
12:06 PM: The teleconference ends with as many questions raised as answered. The dominant one seems to be: what is perchlorate and why is it such a big deal? Even the scientists admitted to having to hit the textbooks on how it works. Perhaps the most intriguing suggestion was that magnesium perchlorate can act as a sort of anti-freeze in the presence of water.
Image: Courtesy of NASA/JPL-Caltech/University of Arizona
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