NASA Unveils Explanation for Mars’ Mysterious “Spiders”

[Article déjà publié le 13 septembre 2024]

For more than 20 years, strange “spiders” have been photographed on the surface of Mars. If this would have been the ultimate proof that life can develop on the red planet, it is not. Indeed, these are not extraterrestrial arachnids but only small geological characteristics.

Until today, NASA itself explained in a press release that “No one really knew how these geological characteristics were created.”However, a recent study published in The Planetary Science Journal On September 11, 2024, highlighted the fact that these Martian “spiders” could be recreated on earth.

The dry ice phenomenon

It is necessary to understand, even if it seems entirely logical, that the conditions of the earth and those of Mars are drastically different. The red planet has not won its nickname because it is synonymous with warmth. On the contrary.

On its surface, according to the CNES, it displays an average temperature of -63 ° C to the equator. And the mercury can descend to -143 ° C and go up to 20 ° C. In short, on Mars, it is very (very) cold. And it is typically thanks to this (very) low temperature that our close neighbor could see “spiders” appear on its surface.

More specifically, these Martian “spiders” are the direct consequence of what is called: dry ice. On earth, we manage to produce it artificially. On Mars, this phenomenon arrives naturally thanks to extremely low temperatures. This dry ice is not ice water, but gas transformed into ice.

More specifically, gas at work and transformed into ice is carbon dioxide (CO2).

How can CO2 be transformed into “spiders”?

This may make one think of the pitch of a bad horror film where astronauts would be trapped on a planet where carbon dioxide can come to life and turn into a form of arachnid. But, fortunately, this is not the case.

No, we owe these Martian “spiders” to a phenomenon of particular change of state: sublimation. The latter consists of the passage of a body of the solid state in the gaseous state directly. This is possible with dry ice, because this CO2 ice cannot go to the liquid state, this gas does not have.

It is therefore this phenomenon that would cause the presence of “spiders” on the surface of Mars.

But that is not done in a snap. It is a long process that spreads over winter to spring explains NASA:

• Icy temperatures trap the CO2 and transforms it into dry ice
• During Martian days, sunlight heats the ground through the transparent dry ice plates accumulated
• The soil being darker than the ice, it therefore absorbs heat and begins the sublimation process
• The more the sublimation is carried out at the level of the floor of March, the more the dry ice is pressurized and ends up cracking
• The cracks do not allow to escape the carbon dioxide trapped
• The latter, by escaping, leads with him dust and sand which comes to settle on the surface of the ice
• In the Martian spring, what we consider to be Martian “spiders” are in fact the remanent of this phenomenon where we just observe dust and sand that filled dry ice cracks

We managed to recreate these “spiders” on earth

Currently, we cannot yet go to Mars. On the other hand, we can bring in Mars to us to carry out different field experiences. This is what Lauren Mc Keown team from NASA JPL (Jet Propulsion Laboratory).

To manage to recreate these “spiders”, NASA scientists relied on the Dirty under-vacuum simulation testbed for icy around Or more simply Dustie. It is a gigantic tube which allows to recreate, on earth, the average pressure and temperature of March.

Their experience therefore consisted in ensuring that Dustie could simulate the conditions of a Martian winter. Then, the researchers made a dumber of Martian soil and released in the carbon dioxide tube. With an extremely low temperature, the latter turned into a dry ice.

Following this, it was necessary to simulate a return to softer temperatures and therefore a progressive warming of the dry ice to give birth to the “spiders”. It was only after several tests that the team of Lauren Mc Keown was able to obtain a convincing result and were therefore able to reply the Martian “spiders”.

However, contrary to what was initially planned, the dry ice which subsequently exploded and therefore revealed the “spiders” did not formed on the surface of the simulated Martian soil. No, Martian “arachnids” were the result of explosion of carbon dioxide coming directly from the interior of the Mars soil and not from its surface.

The search for life on Mars continues

One day we would like to find traces of life on Mars, even very basic. This would mean that our planet is not the only one to have one day sheltered life. But for the time being, this is not yet the case.

However, many missions and many vehicles survey Martian soil in search of the Grail, this proof which would make it possible to say that life indeed existed on Mars.

If we know that liquid water has probably been present on the surface of the planet and that an ocean should be below its surface, almost 20 km deep, for the moment, the presence of life has could not be officially proven.

But research continues and perhaps that the future human presence on the surface of the planet, by 2028 to believe Elon Musk, will allow us to respond all the more quickly to this enigma.

Source : Science / Nasa