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Despite their research for decades, scientists have still not found definitive evidence of life on the red planet, alive today or dead for a long time.
But what they found are tantalizing clues about microbial creatures hidden somewhere in March
So, what are these clues and why are they important?
Before addressing them, it is important to note that when astrobiologists speak of "life", they mean "life as we know it". Aditya Chopra, National University astrobiologist
"What is happening in astrobiology, is that if we want to study life elsewhere, we have to look at life on Earth," he said.
So engineers tend to design interplanetary instruments that seek life signatures common to creatures on Earth.
"Of course, there could be chemical alternatives, things whose life could be researched", Dr. Chopra s First of all: Organic compounds in rocks
Every life form that we we know who lives on Earth today – and probably has already lived – is made of the same organic or carbon-based compounds.
everything goes from simple sugars to the amino acids that make up our muscles. [19659002] In June of this year, NASA's rover Curiosity found organic molecules in old mudstone.
But their presence does not necessarily mean that a biological organism has them
Volcanic vents and the meteorites crushing on the surface of Mars can also produce simple organic compounds, says Dr. Chopra.
While the instruments currently circulating around Mars on the Curiosity rover can only detect compo simple organic ses. It is expected that it will be able to find more complex organic matter pieces, such as amino acids – the building blocks of proteins.
It should also be able to calculate the relative concentrations of simple organic compounds.
s because biological processes create more glucose than other types of sugars.
You do not see this pattern in sugars manufactured, say, by a meteorite collision, says Dr. Chopra
will not only be sensitive to a compound, but to many of them, to determine their concentration and deduce the probability that they were created by biology or not. "
Sniffing methane in the atmosphere
Think methane, and you
But gas is extremely interesting to astrobiologists because it was thought that the first life on Earth was microbes that produced methane
billion years ago, Mars was thought to be a hot and humid planet, just like the Earth, and microbes producing methane could be transported between the two.
Traces gas in the Martian atmosphere were first reported in 2003, spied by Canada-France-Hawaii Telescope in Hawaii.
More recently at Ju Curiosity cyclist showed seasonal fluctuations in levels
Seasonality is a very good case for organic methane, says Dr. Chopra, "because if you get something seasonal, biology is pumped when it can. maybe the conditions are good for liquid water.
While life produces a large amount of methane in the Earth's atmosphere, it does not necessarily mean that methane on Mars is also produced by biological processes.
One way to find out is to measure the different isotopes of methane, where carbon and hydrogen atoms have extra neutrons in their nucleus
Biological methane has an isotopic signature different from geological methane
. "The data should be published later this year on methane isotopes, which can tell us how much could be produced by microbes," said Dr. Chopra.
The Liquid Water for Life
you find life, said Jonti Horner, an astrobiologist at the University of South Queensland.
"That's why NASA had the whole thing following the water."
Mars has not always been an arid and cold desert. An ocean of liquid water could cover up to two-thirds of its surface in its early days.
Although it was long gone, there has always been the possibility that liquid water is hidden underground – with life. "It's cool in the lakes under Antarctica and Greenland, you can find life, so it's a very promising sign," said Professor Horner
On Earth, we are protected from cosmic radiation by our pleasant and thick atmosphere. ] But Mars does not have much atmosphere, so any form of life on the surface would be at the mercy of harmful rays.
A lake 1.5 kilometers underground, like the one announced today, and any life could be called the house would be safe from harmful cosmic rays.
This makes it a new target in the hunt for extraterrestrial life.
Let's go!
The only way to know for sure if the new discovered underground lake teems with life – or is as barren as the Martian surface – is
Well …
one of the biggest technological challenges of our lives, "said Professor Horner. "
First, there is the question of carrying a forest heavy enough to cross all this ice.
Then, you have to land safely.
In 2012, NASA engineers endured "seven minutes of terror" while the Curiosity rover landed.
All landings are not going so well. The Landlord Schiaparelli of the European Space Agency has reached its end in 2016 when he tumbled onto the Martian surface in October 2016, creating a crater where he crashed.
And landing an exercise at the South Pole added For example, the atmosphere is thinner in high latitudes, making the landing even more difficult.
Yet engineers are arguing over how to break through the 10-kilometer ice. Europa, one of the moons of Jupiter. "
" Perhaps we could use a "e "nuclear fusion", then drop a submarine, "said Professor Horner
. Mars in 2020, including the NASA rover, the ExoMars rover of European and Russian space agencies and the triple Chinese feast: an orbiter, an undercarriage and a rover
"If the discoveries continue at the same rate, what will we find? Are we on Mars? Dr. Chopra asked, "We may not need to wait a century to go to Mars and drill it, it could happen in the next five or ten years. "
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