According to data collected by NASA’s MAVEN probe, the small amount of water remaining in the Martian atmosphere is not limited to its lower layer as previously thought, but rises to the upper layer, where it is converted into atomic hydrogen that escapes into space. This phenomenon becomes more pronounced during the southern summer and during the sandstorms on the Red Planet.
Mars used to be a humid planet. Abundant liquid water flows through ancient rivers, lakes and oceans, and it also flows through the atmosphere in the form of gas. Although there is still water left on this arid and cold planet, it is much less than in the past. Although a small amount of vapor is still retained, most of it is contained in its pole cap.
One of the main goals spacecraft The National Aeronautics and Space Administration (NASA) launched the “Martian Atmosphere and Volatile Evolution” report in 2013 and has been using fuel until at least 2030. The purpose is to determine how this water and other compounds disappear from the Martian atmosphere, which will Enables us to better understand the evolution of the Earth’s climate.
The feature of this week is science Provide some answers to the research. The article was produced by researchers from the University of Arizona, Maryland, and NASA’s Goddard Center.
Although traditional models indicate that there is very little atmospheric water left on Mars, the new work provides evidence that it was transported directly to the upper atmosphere, where it was converted into hydrogen atoms and escaped into space.
Data has been collected by mass spectrometer NGIMS (Neutral Gas and Ion Mass Spectrometer) The position of the MAVEN probe when flying over the red planet. The instrument also separates the molecules and ions in the sample based on the weight of the sample, so it can analyze the composition of the Martian atmosphere.
Measuring water ions
The lead author explained to SINC: “We do not directly measure neutral H2O.” Shane Stone, From the University of Arizona,” but we used two NGIMS measurements of water ions: H2 pcsO + with H3O + (They are not so rare, the latter appear in any liquid water sample, including liquid water in our bodies), they are produced by H in the upper atmosphere.2 pcsOr through the reaction with other ions (CO2 pcs + y HCO +)”.
This picture shows how Mars loses water under normal conditions and during dust storms. /NASA/Goddard/CI Labs/Adriana Manrique Gutierrez/Christopher King
He emphasized: “Therefore, through these measurements of water ions, we can calculate the amount of water in the gas sample collected by NGIMS. In addition, the reactive substances in the atmosphere, such as atomic hydrogen (H) and atomic oxygen (O) , Can be recombined in the spectrometer to form H.2 pcsO”.
In this way, researchers have been able to calculate the unexpected amount of water in the upper atmosphere, where water is broken down by various ions to produce atomic hydrogen. It has been observed that this pattern is particularly pronounced in the following situations: Southern Mars in summer And when Sandstorm, Including the one that occurred on the red planet worldwide in 2018.
“During the summer, in the southern hemisphere, when the planets are closer to the sun, the atmosphere of Mars warms, and in the same season it releases sandstorms (many global), causing the atmosphere to warm up; but not on the surface, but in storms It will actually cool down.” Stone explained.
“Warm up is very important, because for Hegro Passa (The layer of cold air where the gas condenses into liquid and forms clouds) To effectively trap water near the surface, it must be cold-he added -. But during the southern summer and during sandstorms, the warming of the atmosphere will cause the tides to pause and heat up, thereby weakening and allowing more water to enter the upper atmosphere.”
The evolution of the Martian climate
According to the authors, this kind of seasonal and sandstorm-mediated contribution of water to the upper atmosphere may have started from the hot and humid state billions of years ago and played a key role in the evolution of the Martian climate. To this day we know the cold, red, dry planet.
Studies have pointed out that most of the water on Mars has slowly been converted into hydrogen and lost to space. This process continues to this day, and billions of years of water have been gradually removed from the earth.
Stone pointed out that this study “helped scientists understand why Mars is so different from Earth, and why its climate has changed so dramatically throughout the history of the solar system.”
Will the water of Mars disappear?
Regarding whether the water on Mars will one day disappear, the researchers recalled that in the past 4.5 billion years, it must have lost the global water layer 10 to 100 meters deep: “That is, if we spread all the water To the surface of Mars, Mars lost planets, then the ocean will be 10 to 100 meters deep.”
Compared with the past, the current atmospheric escape rate on the red planet is relatively small.Other studies published based on data from the MAVEN probe indicate that the solar wind may have swept across the Martian atmosphere at a speed of approximately 100 grams per second.
“This sounds a lot, but compared to the total size of the planet’s atmosphere and the amount of water ice on its surface, it is relatively small, so it will take a long time for atmospheric emissions to clear all the water on Mars.; and our work does not Will not change this conclusion,” Stone concluded.
This graph shows how the amount of water in the Martian atmosphere changes with the seasons. During the global and regional dust storms that occurred in the spring and summer in the southern region, the amount of water surged. /University of Arizona/Sean Stone/NASA Goddard/Dan Gallagher
SW Stone et al. “The escape of hydrogen from Mars is caused by seasonal and sandstorm transportation.” science.