2021-09-25 13:03:13
It is said that we know the surface of the planet Mars better than that of Earth thanks to the many spacecraft that have been providing images from space. However, we know very little about what lurks below the surface.
Mars offers a multitude of landforms on the surface that contain the relics of a remote past much more similar to that of Earth than today. Thus, photographs taken from space have been revealing the existence of ancient seas, now disappeared, riverbeds, now dry, extinct volcanoes, impact craters, large canyons, and deep chasms.
Some of the photographs obtained from space show other smaller landforms that have captured the attention of scientists such as Daniel Viúdez, a researcher at the Center for Astrobiology and our guest on Talking to Scientists. These are dark circles that could be the entrance doors to caves or tunnels that go deep into the Martian soil. Analysis of the images obtained by the Mars Reconnaissance Orbiter (MRO), Mars Odyssey and Mars Global Surveyor of the Elysium Mons region, a huge volcano more than 240 km wide and with a height exceeding 12,500 meters, revealed the existence of at least 32 possible wells with diameters between 100 and 225 meters and depths that oscillate between 68 and 130 meters. But, according to Daniel Viúdez, there are many more, the number of places of this type detected so far exceeds a thousand, the most abundant in the region of Tharsis and Elysium Mons.
What makes it difficult to observe these places is the fact that they have been detected from space, with a view from above and at a great distance, so it is not possible to clearly detect what these holes hide under the surface. The information obtained so far makes it possible to distinguish between two types: pit craters, that is, deep cylindrical openings with steep vertical walls, and skylights over lava tunnels. Daniel Viúdez says that, with the current information, it is not possible to say if they are entrances to caves that extend below the surface, as it happens in many underground caves here on Earth.
Beyond the uncertainties provided by the photographs, the interest of scientists in these openings in the Martian subsoil lies in the possibility that they are the gateway to protected underground spaces where the extreme conditions that exist on the planet’s surface are greatly mitigated. We know that the Martian surface is subjected to freezing temperatures that oscillate dramatically between day and night, it is bombarded by ultraviolet radiation from the Sun, cosmic rays and micrometeorites. On the other hand, the planet does not have a magnetic field that provides a shield against the particles of the solar wind, nor an ozone layer that protects from ultraviolet radiation, in addition, the atmosphere is very tenuous and the pressure is so low that it cannot exist there. liquid water. With these parameters, life on the surface is very unlikely, if not impossible. However, caves or caverns below the surface could offer a protective shield against these adverse conditions for life.
Daniel Viúdez has developed a numerical model that makes it possible to calculate the radiation levels at the entrances of pit craters of various types and sizes, located at different latitudes on the Red Planet. The results have been published in the scientific Icarus. According to the study, the caves could offer protection against direct radiation from the Sun, particles from the solar wind, cosmic radiation and micrometeorites. Sunlight reflected indirectly by the entrance walls of the well or cave could provide enough energy for the development and persistence of microorganisms for long periods of time. On the other hand, these places could also provide a suitable environment to build protected habitats for future earthlings visiting the Red Planet.
I invite you to listen to Daniel Viúdez, researcher at the Centro de Astrobiología.
Reference:
D.Viúdez-Moreiras. The ultraviolet radiation environment and shielding in pit craters and cave skylights on Mars Icarus
Volume 370, December 2021, 114658
Mars and methane. We spoke with Daniel Viúdez Moreiras.
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