(ORDO NEWS) — Even in our cosmic backyard, the solar system, many questions remain open. There are volcano-like formations on Venus, but it is not known if they are active. The surface of Mars is evidence that there was once a huge ocean, but how it disappeared remains unclear.
On the other hand, recent discoveries of chemical compounds that may indicate the presence of biological activity on Mars and Venus, so-called biosignatures, haunt the search for life beyond Earth.
The answers can be found in the analysis of the light that reaches us from these planets, through the “fingerprints” that molecules leave in the spectrum of this light.
In a study published in the journal Atmosphere, scientists from the Instituto de Astrofísica e Ciências do Espaço (Department of Sciences, University of Lisbon, Portugal) compared simulations obtained with the Planetary Spectrum Generator (PSG), a planetary spectrum simulator, with observations of infrared light from the planets Venus. Mars and Jupiter.
Using the PSG developed by NASA, the team was able to explain the results of some of the observations and conclude that this simulator is an effective tool for studying the abundance of chemical compounds present in small amounts in planetary atmospheres.
One of the analyzed chemical compounds, methane, can arise both as a result of biological activity and geological processes. That is why its elusive presence on Mars, with detection by the Mars Express spacecraft and no detection by the ExoMars TGO spacecraft, remains a mystery.
“By changing the parameters of our simulations, we were able to explain these methane detections and non-detections on Mars and understand the conditions and locations in which they can occur.
This is an important step towards clarifying the connection of methane on Mars with the possible existence of life,” explains Pedro Machado (IA & Ciências ULisboa, co-author of this study.
Another unknown on the red planet, also of great interest to the scientific field of the search for life outside the Earth, astrobiology, is the fate of much of its water. Evidence suggests that it once flowed on the planet in abundance, and that much of the northern hemisphere was once a vast ocean. Today Mars is an icy desert.
“Knowing the relationship between the two variants of hydrogen, deuterium isotope and simple hydrogen, helps us understand the temporal evolution of water on Mars.
Deuterium is a heavy hydrogen atom, its nucleus contains one more neutron, so water, H2O, consisting of a deuterium atom and a hydrogen atom, HDO, is heavier and will escape into space with greater difficulty.
Comparing this ratio at a global and local level on Mars, made possible by this study, gives us valuable information about the fate of Martian water, “explains João Dias (IA & Ciências ULisboa), Lead author of the study.
Also in this study, it was noted that phosphine can spontaneously form under conditions of high pressure and temperature in the presence of phosphorus and hydrogen – two chemical elements that make up its composition.
“This is exactly what happens on Jupiter, where phosphine is one of those responsible for the multi-colored bands in the atmosphere of this gas giant,” explains Pedro Machado, “but on a rocky planet like Earth, where such extreme conditions do not exist, its presence is associated with biological activity.”
So when a 2020 study identified phosphine in the clouds of Venus, the scientific community turned its attention to the planet.
“Further studies in other conditions have shown that phosphine may be absent altogether or present in much lower amounts than originally found, which we have also been able to reproduce,” adds Pedro Machado.
Back on Venus, “sulfur dioxide is very important for us to know if there is volcanic activity there. By accurately determining the content of this compound at different altitudes, which we have shown is possible using PSG, we can infer its origin,” – adds Juan Dias.
“This work is of great importance for space missions under development such as the EnVision, Ariel and Mars Express of the European Space Agency (ESA) in which IA is involved, as it allows to determine the expected values for these chemical components and optimize the instruments developed for these missions, for detection in the range of expected values,” says Pedro Machado, who is one of the researchers on these missions.
“In particular, missions such as Ariel, which will study the atmospheres of planets orbiting stars other than the Sun, exoplanets, benefit greatly from this kind of solar system exploration, which can serve as a model for what we hope to be able to observe beyond solar system,” adds João Dias.
“This demonstration of the effectiveness of PSG is very important to the scientific community, and AI is at the forefront of this research, including specialists in the planetary systems team who study the atmospheres of planets in the solar system.”
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