On Mars, we found the lake. How to change now the search for life on the Red Planet?
Last week, the search for life on Mars has become more interesting. For decades, scientists have peered into the red desert of the dry and dusty planet, trying to highlight the areas in which life could take root when the Martian climate was warm and wet billions of years ago. But on July 25, scientists announced that they have found signs of the presence of a large lake with liquid water under a thick layer of ice near the south pole of the planet.
If confirmed the existence of the lake, perhaps we will find it and microbes.
In general, this discovery changed the attitude of astrobiologists, who want to protect any existing extraterrestrial life from destruction by accidentally listed species on Earth. Rovers and descends cleaned to exacting standards, to avoid any possible zaglyazneniya, says astrobiologist Lisa Pratt of NASA planetary protection department. "Possible subglacial lake! This significantly changes the type of environment that we are trying to protect. "
How is the search for life on Mars after the discovery of the lake?
The first question. Can anyone actually live in this lake?
For the majority of terrestrial microbes it will be harsh environment. Life on Earth fills every niche you can find from the cave of crystals to arid deserts. However, the lower temperature limit for most of the earth's life - -40 degrees Celsius. Temperature Mars ice crust of about -68 degrees.
"It is very cold, colder than in any environment on Earth, which in our opinion may be reproduced or life," says Pratt.
The lake contains a lot of water. But to keep the water liquid at such a low temperature, it must be extremely salty. "On Earth, this kind of salty mixtures do not give quietly to live organisms," says planetary scientist Jim Bell of Arizona State University in Tempe. "Even bacteria extremophile that can live in salt water, can not survive." Are there Martians live?
"Absolutely," says Pratt.
If life arose on Mars in the past, when the planet was more friendly, some organisms can adapt to climate change and calmly continue to dwell in the cold salt water, she says. "As for me, this is a perfect getaway where you can just be, maybe doze off and wait until the surface conditions will be better.
The lake is different from other water bodies in which we hope to find life, such as those on Enceladus?
For researchers the planet Mars has one big advantage compared to other icy moons of Saturn and Jupiter: we have already visited. Get to Mars can be relatively quickly, in just 4-11 months, and the planet's atmosphere makes it easy landing, as opposed to small airless moons.
The big question for planetary defense is whether the Martian lake in contact with the surface. Enceladus and perhaps on Europe subsurface liquid water ocean spills into the sky through the cracks in the ice. These geysers can greatly simplify the fence ocean samples: the spacecraft will have enough to fly through it. But the fact that the water goes out, means that germs can move freely.
Although next to a lake on Mars until it landed spacecraft, dust storms can carry pollution across the planet.
"If the lake is real, let's hope that passengers had not penetrated," says Pratt.
If there is no way to get to the lake, or get out of it, how do we know that there is life?
This is a great question.
To check lake for signs of life, "it is necessary to drill him" way, said Isaac Smith of the Institute of Planetary Science in Lakewood, Colorado. That's what scientists have probed similar subglacial lake in the world, such as Lake Vostok that scientists from Russia was drilled in 2012. Then they said that the lake is living an active life, but later admitted that the samples were contaminated. Drilling on Mars may be more technically challenging and face the pressure of the scientific community, as in the case of the Russian team. "Like a subglacial lake in Antarctica, Lake Mars may find extremely rare and special place," says Pratt. "I expect that drilling will meet a lot of resistance."
But if we are lucky, you can do without it. Symptoms of seasonal variations of methane in the Martian atmosphere aroused interest among astrobiologists because they can point to a life beneath the surface. ExoMars, the unit of the European Space Agency and Roscosmos, which began collecting data in April, searches for more methane.
"ExoMars could find the smoke, so to speak," says planetary scientist Roberto Orosei from the National Institute of Astrophysics in Bologna, Italy, who was in command, open the lake. "Combining liquid water and methane in the atmosphere would eloquent testimony of what is happening on Mars."