The Weather Network – Life on Mars? NASA InSight could help solve this mystery

For decades, scientists have been trying to answer an important question: Is there life on Mars?

However, it is not about life on Mars in the distant past of the planet. It's about knowing there is life on the red planet now.

The NASA Viking landing gear tried for the first time in 1976. Their results can only be described as "inconclusive". Although the first results returned generated enthusiasm, it turned out that they could not indicate the presence of life. Some scientists swear by the initial conclusion.

For over 40 years, a collection of orbits, undercarriages and rovers have collected more data. They revealed that Mars – now a cold, arid planet – had certainly had a warmer and wetter environment long ago, capable of sustaining primitive life. They also showed that there were places where life could exist now: vast deposits of pure ice beneath the surface of the planet and even a lake of liquid water under at least one of these ice deposits .

In one of the most recent discoveries, a team of researchers found evidence of an old groundwater system covering the entire planet on Mars. Using cameras onboard the Mars Express orbiter, they spotted deep crater features all around the northern hemisphere of the planet that could only be formed with water, the planet's oceans gradually retreating underground.

Distribution of once watery basins on Mars. Credit: NASA / MGS / MOLA, F. Salese et al. (2019)

These robots even spotted methane – a gas closely related to life on Earth – that escapes from the surface of Mars.

WHAT'S NEW MARCH METHANE?

Mars has a complicated history with methane. Sometimes it's there and sometimes not. We even saw a seasonal variation.

Indices have been observed using terrestrial telescopes. Orbiters have spotted it from the space. NASA's Curiosity robot has also detected methane from the ground.

Over the past two weeks, we have also received exciting news from the Mars Express spacecraft of the European Space Agency. Scientists examining the data from its instruments were able to confirm the same methane detection as that made by the Curiosity mobile in July 2013.

Mars Express is the peak of methane measured by Curiosity. Credit: Giuranna et al. (2019)

This confirmation is extremely important because it tells scientists that Curiosity's detection of methane was not a coincidence or error. With two independent detections, the peak of methane has really arrived!

The complicated part comes from the fact that, for each detection of methane detected on Mars, there seems to be a contradictory measure indicating that the methane is gone.

Just this week, it was revealed that data from the Exorbar Trace Gas Orbiter of ESA, which had begun to scan the atmosphere of Mars in April 2018, revealed no sign of methane in the air.

Key measurements of methane on Mars. Credit: ESA

Practical experiments have shown that methane decomposes in the atmosphere of Mars in less than ten years. That's why it can be such a good sign to look for when looking for life. Since it does not last hundreds of years, let alone millions, even billions of years, if you detect it, the methane must have been produced or at least released into the atmosphere, quite recently.

The latest data seem to suggest that Mars' methane is disappearing much faster, perhaps in the order of five years. This raises the question of what removes methane so quickly.

On the other hand, if methane is quickly removed from the atmosphere of Mars, what continues to produce methane that we detect?

BIOLOGY OR GEOLOGY?

Biological life produces methane. We find it here on Earth. For this reason, methane is one of the atmospheric gases that exoplanet scientists have on their list of potential life signs on extraterrestrial worlds.

The surface conditions of Mars are deadly for most life forms we know, with freezing temperatures, low atmospheric pressure, toxic chemicals for the soil and intense radiation from space. It is possible that terrestrial microbes survive inside or below rovers and undercarriages, where they are protected from radiation.

If there is life on Mars – the life that has actually developed there, rather than hitchhiking from Earth – it will probably be at some distance underground. There, the microbes would produce methane as part of their metabolism.

Biology is not the only way to get methane, though.

As part of the investigation on methane on Mars, scientists have indicated that there is also a geological way to produce it. This requires that the olivine mineral be exposed to extreme heat (for example in contact with a magma), while it is in the presence of water.

The big question is which of these sources is the most likely source of methane from Mars.

Seasonal variation in methane could be more reminiscent of biology, if it were a planet like Earth. Seasonal variations in temperature would make life at the surface more active during warm periods and less active during cold periods. Martian microbes, if they exist, would live underground, where the impact of seasonal temperature changes is less. They would probably be active all year.

However, seasonal changes would produce cracks and fissures in the underground ice, which would allow the trapped methane to seep to the surface – whether the methane comes from biology or geology.

This is where the insight comes

Why is NASA InSight important for this research?

InSight has not been sent to Mars in search of life. There is no instrument capable of detecting methane. He has a seismometer to detect marsquakes. It has a weather station. He has a special radio experience to watch the "flickering" of the planet. Finally, it has a thermal probe instrument, nicknamed "The Mole".

NASA-InSight-Heat-Probe- 1600 "data-img =" // images.twnmm.com/c55i45ef3o2a/4iFOSYGnrq7TLZam7H7P3q/4cbe5ee0ca616bfa62a5083ba101abdd/NASA-Hours-
In this chart, the NASA InSight LG is shown with its deployed instruments, including the HP3 "Heat Probe", bottom right, tapping into the surface to take the temperature of the planet . Credit: NASA / JPL-Caltech

This last instrument, the heat flux and physical properties probe, or HP ^ 3, is the one that could perhaps provide us with the next big step forward in the search for life on Mars.

According to Jim Green, chief scientist of NASA, when The Mole will be fully deployed, it will allow planetary scientists to develop the first temperature profile of the interior of Mars. This profile will tell us how much the planet has cooled, if the core of Mars is still hot enough to be liquid and how close to the surface magma could be.

AND AFTER?

It is undeniable that to answer definitively the question "Is there any life on Mars", it will be necessary to dig a Martian microbe and examine it under a microscope. Even then, we will have to make sure that it's not just a microbe that's hooked to one of our robots from Earth.

In the meantime, however, until we can build a robot capable of doing it, or until we can do it ourselves, all the missions we have on and over Mars will continue to add to our case – even the ones who have not even been sent with this question in mind.

With regard to InSight of 11 April, the scientists in charge of the HP ^ 3 instrument are still working on the deployment of the thermal probe. Last February, when NASA ordered the lander to begin the mole's The Mole sequence pounding beneath the surface, it was suddenly suspended, about 30 centimeters deep.

This animation, made from images from the InSight Instrument Deployment Camera (IDC), shows one of NASA 's hammer tests. The attempt causes a slight increase in the case HP ^ 3, then a new stabilization. Credit: NASA / JPL

For the moment, according to Tilman Spohn, the head of the HP ^ 3 instrument, they are working on three different possibilities:

1) The cable that hangs behind the probe is hanging on something inside its protective case, although they have determined that this could only happen in very specific circumstances,
2) There is a large rock that can not currently be bypassed or pushed, but the rocks seen on the surface indicate that there should not be any particularly large ones under the ground, and
3) The soil that the probe is trying to hammer does not stick very well together. Thus, with each downward pressure, the probe bounces slightly and the material fills below, so it can not progress.

The InSight team always tries to determine the correct problem, but the third option could be this one (and perhaps the easiest to solve).

Once they understand all this, then they can continue with this part of the mission. Then we can finally get an idea of ​​what the interior of Mars looks like and what it means for other things, such as the search for life.

Sources: NASA | ESA | DLR

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