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NASA / ESA
NASA's Hubble Space Telescope snapped this shot of Mars on Aug. 26, 2003, when the Red Planet was 34.7 million miles from Earth. The picture was taken just 11 hours before Mars made its closest approach to us in 60,000 years.
By Rod Pyle
Space.com
LOS ANGELES — While Mars was likely a more hospitable place in its wetter, warmer past, the Red Planet may still be capable of supporting microbial life today, some scientists say.
Ongoing research in Mars-like places such as Antarctica and Chile's Atacama Desert shows that microbes can eke out a living in extremely cold and dry environments, several researchers stressed at "The Present-Day Habitability of Mars" conference held here at the University of California Los Angeles this month.
And not all parts of the Red Planet's surface may be arid currently — at least not all the time. Evidence is building that liquid water might flow seasonally at some Martian sites, potentially providing a haven for life as we know it.
"We certainly can't rule out the possibility that it's habitable today," said Alfred McEwen of the University of Arizona, principal investigator for the HiRise camera aboard NASA's Mars Reconnaissance Orbiter spacecraft. [The Search for Life on Mars: A Photo Timeline]
NASA / JPL-Caltech / Univ. of Arizona
This image combining orbital imagery with 3-D modeling shows flows that appear in spring and summer on a slope inside Mars' Newton crater.
Surface water on Mars?
McEwen discussed some intriguing observations by HiRise, which suggest that briny water may flow down steep Martian slopes during the local spring and summer.
Sixteen such sites have been identified to date, mostly on the slopes of the huge Valles Marineris canyon complex, McEwen said. The tracks seem to repeat seasonally as the syrupy fluids descend along weather-worn pathways.
While the brines may originate underground, Caltech's Edwin Kite noted, there is an increasing suspicion that a process known as deliquescence — in which moisture present in the atmosphere is gathered by compounds on the ground, allowing it to become a liquid — may be responsible.
Astrobiologists are keen to learn more about these brines, for not much is known about them at the moment.
"Briny water on Mars may or may not be habitable to microbes, either from Earth or from Mars," McEwen said.
NASA / JPL-Caltech / MSSS
NASA's Curiosity rover found evidence for an ancient, flowing stream on Mars at a few sites, including the rock outcrop pictured here, which the science team has named "Hottah" after Hottah Lake in Canada's Northwest Territories. This image mosaic was taken by Curiosity's 100-millimeter Mastcam telephoto lens.
Hardy microbes
Martian life may be able to survive even in places where water doesn't seep and flow, some scientists stressed.
For example, microbes here on Earth make a living in the Atacama and the dry valleys of Antarctica, both of which are extremely cold and arid, said Chris McKay of NASA's Ames Research Center in Moffett Field, Calif.
Antarctic sites also receive seasonally high ultraviolet radiation doses thanks to a hole in the ozone layer that tends to develop every August through November. This provides yet another parallel to Mars, whose thin atmosphere and lack of a protective magnetic field make the planet more radiation-bombarded than Earth.
In the Antarctic dry valleys, McKay said, organisms dwell within rocks, just deep enough to be shielded from the worst of the UV but close enough to the surface to receive the benefits of photosynthesis. Something similar might be happening on Mars today, if life ever evolved there.
McKay also discussed deliquescence, which in the Atacama allows salts to gather enough water to support the existence of life.
McKay offered some advice to NASA's Mars rover Curiosity, which landed in August to determine whether Mars could ever have supported microbial life: "Watch for salt along the road!"
A possible energy source
A number of presenters spent some time talking about perchlorate, a chlorine-containing chemical that NASA's Phoenix lander spotted near the Martian north pole in 2008.
McKay and other researchers think perchlorate may be the reason that NASA's twin Viking landers didn't detect any organic compounds — the carbon-containing building blocks of life as we know it — on the Red Planet back in the 1970s.
The Vikings vaporized Martian soil and looked for any organics boiling off. They found nothing but a few chlorine compounds that were attributed to contamination. But after Phoenix's perchlorate find, McKay and some other researchers performed an experiment.
They added perchlorate to some desert dirt from Chile known to contain organics. They heated the soil up and found the same chlorine compounds the Vikings did, suggesting that organics may have been present in the Vikings' samples but were broken down by the combination of heat and perchlorate.
While this backstory is interesting in its own right, perchlorate is also relevant to the possible habitability of present-day Mars.
"Perchlorate, it turns out, is a potent chemoautotrophic energy source," said Carol Stoker, also of NASA Ames, noting that the chemical could potentially sustain microbes in the dark Martian subsurface, where photosynthesis is not an option.
And some Earth microbes use perchlorate for food, so that could be happening on Mars as well, scientists have pointed out.
"The Present-Day Habitability of Mars" took place Feb. 4-5 and was co-hosted by the NASA Astrobiology institute and the UK Center for Astrobiology. Archived videos of conference presentations are available here.
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Leave a Comment:
It is 70 degrees and sunny on Mars.
Possible afternoon showers.
But I've got this terrible oxygen habit, I'm up to like 200 gallons a day
Doug, buddy, I think it's time to admit you have a problem.
You're addicted to respiration. Don't worry, there's a group for that.
“water may flow down steep Martian slopes during the local spring and summer”
WHAT? Wait a second…that is not what we have been told over and over again…that Mars is a cold barren planet devoid of life with only a scant atmosphere. A virtually water less, dry rust-colored planet with a rust-colored sky; polar caps composed of only CO2.
What’s going on here?
Could it be that “they” are slowly letting the cat out of the bag?
Fool me once, shame on you; fool me twice……fool us a hundred times….well - shame on all of us.
> wilieturner Could it be that “they” are slowly letting the cat out of the bag?
Or, it could be that they are learning things and discovering things along the way. I don't think there's a long conspiracy to 'hide' the Martian truth from us. Science moves at the speed of science.
The conventional idea is that liquid water can't exist in such low pressure - but scientist think that a very salty brine may be able to exist in a liquid form, even at the low temps and low pressures. That's not a conspiracy - it's just a discovery.
Why do you assume that findings being reported to us as new discoveries are actually old discoveries being revealed to us now for no apparent reason?
The majority of all space science is educated guesses and modeling rather than direct observation and physical testing. Of course they're going to get things wrong and make corrections as they learn the truth.
jeez, of COURSE Mars has water, whadaya think flows in the CANALS !
If it worked on Mars the same way it worked on Earth, with the oceans and all, then any life still there would have had to have gotten its start billions of years ago. Kinda hard to believe it may have survived so long on that planet.
Not for nothing, but Europa is supposed to be one big, and possibly saltwater ocean. Why not go check that place out? Same basic conditions as the bottom of our oceans, where life is abundant.
Keep in mind that the ground itself is a form of atmosphere, which can potentially harbor microscopic life. For this reason, I personally believe we will find life to be ubiquitous in the future, even potentially here on our own Earth's moon Luna. - RC
The best way to find life on Mars is to culture microscopic samples of soil in sterile culture media. A micro drilling rig can drill for these micro culture samples several yards underground, particularly at the Martian poles. When are we finally going to send a roving laboratory to Mars which can do this, and which can even potentially load up positive samples into a Martian excursion module for eventual return to Earth? - Rick Carter
(I personally think Martian surface probes should use Phobos as a way station when it comes to returning promising samples back here to Earth. In my opinion, we should first establish a future underground habitable station / colony inside of Phobos, which we can visit with Martian fly around missions in the future. Our Martian probes would return pre-qualified samples from Mars to Phobos, for pickup and transportation by future astronauts back here to Earth.)
What makes Phobos a better potential site for a station/colony than Mars?
How would you formulate the culture medium? With incomplete knowledge of the soil chemistry it would be a total shot in the dark, the presence or absence of micro-nutrients can make a huge difference to organisms here on Earth so it's reasonable to assume the same is true for Mars.