Four billion years ago the surface of Mars, apparently, was quite a suitable habitat. Through it flowed a river and lake, there was even a deep ocean. Some astrobiologists consider ancient Mars as a cradle for life, even more habitable than Earth, and I suspect that life on our planet may have appeared long ago on the Martian rocks were ejected into space by a powerful blow.
That all changed, when Mars lost its global magnetic field. Charged particles emanating from the Sun, had the opportunity to carry the Martian atmosphere and that gradually depleted. This process turned Mars into a cold, dry world we see today, even 3.7 billion years ago. The Earth’s global magnetic field still remains, which explains the suitability of our planet for life.
But this turn of events does not mean that Mars today is a dead planet.
“If life were on Mars 4 billion years ago, life exists on Mars now. Nothing that would have destroyed life on Mars didn’t happen,” says Michael Finney, co-founder of The Genome Partnership, a nonprofit organization that holds conferences on the theme of advances in biology and technology of the genome.
“If Mars had life, it would have gone somewhere, perhaps hiding, but probably would still be there,” says Finney.
One of the most promising shelter for life is the underground part of Mars. Although on the surface of the red planet in our days there is no liquid water except perhaps time flows on warm slopes and in underground aquifers, most likely, a lot of moisture. Observations from the Orbiter Mars Express in Europe show that, under the South pole of the red planet may be hiding a big lake.
Motley inhabitants of the Earth speak of their presence very obvious way; an advanced alien civilization probably could quite quickly understand the existence of life on our planet, just scan our atmosphere.
We do not see such obvious traces in the Martian air, but recently, scientists found some interesting things. The Rover “Curiosity” NASA passed through two jets of methane in the Gale crater with a width of 154 km. This crater is six-wheeled robot explores since landing in 2012. The mission of the Rover was also determined that the concentration of methane in the air at the Gale crater vary depending on the season.
More than 90% of methane in the Earth’s atmosphere is produced by microbes and other organisms, so it is possible that this gas is said about the modern Martian life.
But debates on this subject are still ongoing. Methane also can produce lifeless processes, for example, the reaction of hot water with certain breeds. And even if Martian methane is biological in origin, his created beings can be long dead. Scientists believe that methane geysers on Mars broke out of the ground and no one knows how long the gas layer remained imprisoned at the bottom before you get to the surface.
In the search for Martian DNA
The NASA Rover, which will go to the planet in 2020, next summer, will look for signs of long-dead life. The same will be engaged and the European-Russian ExoMars Rover mission which will start around the same time.
But some scientists want to expand this hunt and the life that can 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 the three main researchers in the project “Search for extraterrestrial genomes” (SETG), which is developing a tool to detect past or present life based on DNA or RNA on Mars and other alien worlds.
Part of this idea is based on panspermia, the idea that life spread widely throughout the Solar system and possibly throughout the galaxy, natural or by artificial means. If life really came to Earth from somewhere else, it is likely that it once thrived on Mars. The red planet could become sources of life, or were “seeded” Earth.
Ruvkun considers panspermia as a very probable theory. The main argument in its favor is very early appearance of ATP-synthase, the enzyme that provides the appearance of a molecule of adenosine triphosphate.
ATP-synthase, according to Ruvkun fully ascend 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 life started to exist. The fact that she was too quickly developed. That is why the idea of panspermia is so attractive”.
If panspermia is correct, any life forms we find on Mars or elsewhere in our Solar system is likely to be associated with us. That is, these organisms will use DNA or RNA as its genetic molecule. So we have to look for this material.
“It would be foolish not to look for DNA on Mars,” says Ruvkun. “It’s an experiment that should hold”.
Not only Mars
Mars is not the only place in our Solar system, where today could flourish in alien life. Most astrobiologists would put the Red planet at the end of the list, putting forward a moon of Jupiter Europe, and the moons of Saturn, Enceladus and Titan.
Under the ice shields of Europe and Enceladus hiding deep oceans of liquid salt water. Titan is also believed to have an ocean of water, and on the surface of this satellite found lakes and seas of liquid hydrocarbons.
Even the red-hot Venus might place quite habitable spaces.
Like Mars, Venus was once rich in water on the surface, but unstoppable greenhouse effect all fried and left the planet with temperatures which melted lead. However, at the height of 50 kilometers above the surface of Venus is quite possible to live.
What the world will find the first extraterrestrial life?