On Mars, life can be. But how to find it?
Four billion years ago, Mars, apparently, was quite a habitable. According to her flowing rivers and lakes, there was even the deep ocean. Some astrobiologists regard as the cradle of ancient Mars for life, even more suitable than the Earth, and suspect that life on our planet may have appeared a long time ago on Martian rocks and was ejected into space powerful blow.
Everything changed when Mars lost its global magnetic field. Charged particles from the sun, were able to take the Martian atmosphere and that gradually depleted. This process turned Mars into the cold, dry world that we see today, even 3, 7 billion years ago. At the Earth's global magnetic field remains, which explains the suitability of our planet for life.
But this turn of events does not mean that Mars today - a dead planet.
"If life was on Mars 4 billion years ago, life on Mars now. Nothing that would destroy life on Mars is not happening, "says Michael Finney, co-founder of The Genome Partnership, a nonprofit organization that conducts a conference on advances in biology and genome technologies.
"If there was life on Mars, it would have gone somewhere else, perhaps to hide, but probably would still be there," says Finney.
Life on Mars underground
One of the most promising shelter life is the underground part of Mars. Although on the surface of the Red Planet today there is no liquid water - except, perhaps, time flows on the warm slopes - in underground aquifers, most of all, a lot of moisture. Observations orbiter Mars Express in Europe show that under the south pole of the red planet could be hiding a large lake. Motley inhabitants of the Earth say their presence is very obvious way; advanced alien civilization could probably quickly realized the presence of life on our planet, simply by scanning our atmosphere.
We do not see such obvious traces in the Martian air, but recently, scientists have found some interesting things. Rover "Kyuriositi" NASA passed through two jets Methane the crater Gale width of 154 kilometers. This crater six-wheeled robot explores ever since landing in 2012. rover mission also determined that the concentration of methane in the air in the crater Gale vary depending on the season.
More than 90% of methane in Earth's atmosphere is produced by microbes and other organisms, so it is possible that the gas talks about the modern Martian life.
But the debate on this issue are ongoing. Methane can also produce lifeless processes, such as hot water reaction with certain breeds. And even if Martian methane of biological origin, who created his creatures may be long dead. Scientists believe that methane geysers on Mars made their way out of the ground, and no one knows how long the gas layer remained at the bottom sharpened before to get to the surface.
In search of Martian DNA
NASA's Mars rover, which will go to the planet in 2020, next summer, will be looking for signs of long-dead life. The same will and the European-Russian ExoMars rover, mission to be launched around the same time. But some scientists want to expand this hunt and to life that may exist to this day. One of them was a molecular biologist Gary Ruvkun, who works at Massachusetts General Hospital and Harvard Medical School.
Ruvkun - one of three principal investigators in the project "Search for Extraterrestrial Genomes" (SETG), which is developing a tool to detect past or present life on the basis of DNA or RNA on Mars and other alien worlds.
Some of this is based on the idea of panspermia, the idea that life is widely spread throughout the solar system, and perhaps throughout the galaxy, either naturally or artificially. If life really came to Earth from somewhere else, it is likely that she had once flourished on Mars. The red planet could become sources of life, or was "planted" as the Earth.
Ruvkun considering panspermia as a very plausible theory. The main argument in its favor, he thinks very early appearance of ATP synthase, the enzyme that provides the appearance of ATP molecules.
ATP synthase, according Ruvkuna completely back to the base of the tree of life on Earth, which means that this complex molecule appeared about 4 billion years ago.
"It's not just that there was life in general. The fact that it has evolved too quickly. That's why the idea of panspermia is so attractive. "
If panspermia is correct, all forms of life that we find on Mars - or anywhere else in our solar system - likely to be associated with us. That is, these organisms will use DNA or RNA as the genetic molecule. So, we must look for this stuff. "It would be foolish not to look for DNA on Mars," says Ruvkun. "This is an experiment that is worth spending."
Not only Mars
Mars - the only place in our solar system, which today could be extraterrestrial life to flourish. Most astrobiologists would put the red planet at the end of the list, putting forward the Jupiter moon Europe and Saturn's moons Enceladus and Titan.
Under the ice shield in Europe and Enceladus hiding deep ocean of liquid salt water. Titan also is believed to have a water ocean, and found the lakes and seas of liquid hydrocarbons on the surface of the satellite.
Even the red-hot Venus might have the quite inhabited spaces.
As Mars, Venus was once rich water on the surface but uncontrollable greenhouse all toasted and left planet with the temperatures at which melt lead. However, at an altitude of 50 kilometers above the surface of Venus is quite possible to live.
What do you think, on what planet would find the first extraterrestrial life?