The atmosphere on Mars for humans. Brief history of the study

Mars is the fourth planet from the Sun and the last of the terrestrial planets. Like the rest of the planets in the solar system (not counting Earth), it is named after the mythological figure - the Roman god of war. In addition to its official name, Mars is sometimes called the Red Planet, due to the brownish-red color of its surface. With all this, Mars is the second smallest planet in the solar system after.

For almost the entire nineteenth century, it was believed that life existed on Mars. The reason for this belief is partly error and partly human imagination. In 1877, astronomer Giovanni Schiaparelli was able to observe what he believed were straight lines on the surface of Mars. Like other astronomers, when he noticed these stripes, he assumed that such directness was associated with the existence of intelligent life on the planet. A popular theory at the time about the nature of these lines was that they were irrigation canals. However, with the development of more powerful telescopes in the early twentieth century, astronomers were able to see the Martian surface more clearly and determine that these straight lines were just an optical illusion. As a result, all earlier assumptions about life on Mars remained without evidence.

Much of the science fiction written during the twentieth century was a direct consequence of the belief that life existed on Mars. From small green men to towering invaders with laser weapons, Martians have been the focus of many television and radio programs, comic books, films and novels.

Despite the fact that the discovery of Martian life in the eighteenth century ultimately turned out to be false, Mars remained for scientific circles the most life-friendly planet (not counting Earth) in the solar system. Subsequent planetary missions were undoubtedly dedicated to the search for at least some form of life on Mars. Thus, a mission called Viking, carried out in the 1970s, conducted experiments on Martian soil in the hope of finding microorganisms in it. At that time, it was believed that the formation of compounds during experiments could be the result of biological agents, but it was later discovered that compounds of chemical elements could be created without biological processes.

However, even these data did not deprive scientists of hope. Having found no signs of life on the surface of Mars, they suggested that all the necessary conditions could exist below the surface of the planet. This version is still relevant today. At the very least, planetary missions of the present such as ExoMars and Mars Science involve testing all possible options for the existence of life on Mars in the past or present, on the surface and below it.

Atmosphere of Mars

The composition of the atmosphere of Mars is very similar to that of Mars, one of the least hospitable atmospheres in the entire solar system. The main component in both environments is carbon dioxide (95% for Mars, 97% for Venus), but there is a big difference - there is no greenhouse effect on Mars, so the temperature on the planet does not exceed 20°C, in contrast to 480°C on the surface of Venus . This huge difference is due to the different densities of the atmospheres of these planets. With comparable densities, Venus's atmosphere is extremely thick, while Mars has a rather thin atmosphere. Simply put, if the atmosphere of Mars were thicker, it would resemble Venus.

In addition, Mars has a very rarefied atmosphere - atmospheric pressure is only about 1% of the pressure on Earth. This is equivalent to a pressure of 35 kilometers above the Earth's surface.

One of the earliest directions in the study of the Martian atmosphere is its influence on the presence of water on the surface. Despite the fact that the polar caps contain solid water and the air contains water vapor resulting from frost and low pressure, all research today indicates that the “weak” atmosphere of Mars does not support the existence of liquid water on the surface planets.

However, based on the latest data from Mars missions, scientists are confident that liquid water exists on Mars and is located one meter below the surface of the planet.

Water on Mars: speculation / wikipedia.org

However, despite the thin atmospheric layer, Mars has weather conditions that are quite acceptable by terrestrial standards. The most extreme forms of this weather are winds, dust storms, frost and fog. As a result of such weather activity, significant signs of erosion have been observed in some areas of the Red Planet.

Another interesting point about the Martian atmosphere is that, according to several modern scientific studies, in the distant past it was dense enough for the existence of oceans of liquid water on the surface of the planet. However, according to the same studies, the atmosphere of Mars has been dramatically changed. The leading version of such a change at the moment is the hypothesis of a collision of the planet with another fairly voluminous cosmic body, which led to Mars losing most of its atmosphere.

The surface of Mars has two significant features, which, by an interesting coincidence, are associated with differences in the planet's hemispheres. The fact is that the northern hemisphere has a fairly smooth topography and only a few craters, while the southern hemisphere is literally dotted with hills and craters of different sizes. In addition to topographical differences, which indicate differences in the relief of the hemispheres, there are also geological ones - studies indicate that areas in the northern hemisphere are much more active than in the southern.

On the surface of Mars is the largest known volcano, Olympus Mons, and the largest known canyon, Mariner. Nothing more grandiose has yet been found in the Solar System. The height of Mount Olympus is 25 kilometers (that's three times higher than Everest, the tallest mountain on Earth), and the diameter of the base is 600 kilometers. The length of the Valles Marineris is 4000 kilometers, the width is 200 kilometers, and the depth is almost 7 kilometers.

The most significant discovery about the Martian surface to date has been the discovery of canals. The peculiarity of these channels is that, according to NASA experts, they were created by flowing water, and thus are the most reliable evidence of the theory that in the distant past the surface of Mars was significantly similar to the earth's.

The most famous peridolium associated with the surface of the Red Planet is the so-called “Face on Mars”. The terrain actually closely resembled a human face when the first image of the area was taken by the Viking I spacecraft in 1976. Many people at the time considered this image to be real proof that intelligent life existed on Mars. Subsequent photographs showed that this was just a trick of lighting and human imagination.

Like other terrestrial planets, the interior of Mars has three layers: crust, mantle and core.
Although precise measurements have not yet been made, scientists have made certain predictions about the thickness of the crust of Mars based on data on the depth of Valles Marineris. The deep, extensive valley system located in the southern hemisphere could not exist unless the crust of Mars was significantly thicker than that of Earth. Preliminary estimates indicate that the thickness of Mars' crust in the northern hemisphere is about 35 kilometers and about 80 kilometers in the southern hemisphere.

Quite a lot of research has been devoted to the core of Mars, in particular to determining whether it is solid or liquid. Some theories have pointed to the absence of a strong enough magnetic field as a sign of a solid core. However, in the last decade, the hypothesis that the core of Mars is at least partially liquid has gained increasing popularity. This was indicated by the discovery of magnetized rocks on the planet's surface, which may be a sign that Mars has or had a liquid core.

Orbit and rotation

The orbit of Mars is remarkable for three reasons. Firstly, its eccentricity is the second largest among all the planets, only Mercury has less. With such an elliptical orbit, Mars' perihelion is 2.07 x 108 kilometers, which is much further than its aphelion of 2.49 x 108 kilometers.

Secondly, scientific evidence suggests that such a high degree of eccentricity was not always present, and may have been less than Earth's at some point in the history of Mars. Scientists say the reason for this change is the gravitational forces of neighboring planets acting on Mars.

Thirdly, of all the terrestrial planets, Mars is the only one on which the year lasts longer than on Earth. This is naturally related to its orbital distance from the Sun. One Martian year is equal to almost 686 Earth days. A Martian day lasts approximately 24 hours and 40 minutes, which is the time it takes for the planet to complete one full revolution around its axis.

Another notable similarity between the planet and Earth is its axial tilt, which is approximately 25°. This feature indicates that the seasons on the Red Planet follow each other in exactly the same way as on Earth. However, the hemispheres of Mars experience completely different temperature regimes for each season, different from those on Earth. This is again due to the much greater eccentricity of the planet’s orbit.

SpaceX And ​​plans to colonize Mars

So we know that SpaceX wants to send people to Mars in 2024, but their first Mars mission will be the Red Dragon capsule in 2018. What steps is the company going to take to achieve this goal?

• 2018 Launch of the Red Dragon space probe to demonstrate technology. The goal of the mission is to reach Mars and do some survey work at the landing site on a small scale. Perhaps supplying additional information to NASA or space agencies of other countries.
• 2020 Launch of the Mars Colonial Transporter MCT1 spacecraft (unmanned). The purpose of the mission is to send cargo and return samples. Large-scale demonstrations of technology for habitat, life support, and energy.
• 2022 Launch of the Mars Colonial Transporter MCT2 spacecraft (unmanned). Second iteration of MCT. At this time, MCT1 will be on its way back to Earth, carrying Martian samples. MCT2 is supplying equipment for the first manned flight. MCT2 will be ready for launch once the crew arrives on the Red Planet in 2 years. In case of trouble (as in the movie “The Martian”) the team will be able to use it to leave the planet.
• 2024 Third iteration of Mars Colonial Transporter MCT3 and first manned flight. At that point, all technologies will have proven their functionality, MCT1 will have traveled to Mars and back, and MCT2 will be ready and tested on Mars.

Mars is the fourth planet from the Sun and the last of the terrestrial planets. The distance from the Sun is about 227940000 kilometers.

The planet is named after Mars, the Roman god of war. To the ancient Greeks he was known as Ares. It is believed that Mars received this association due to the blood-red color of the planet. Thanks to its color, the planet was also known to other ancient cultures. Early Chinese astronomers called Mars the “Star of Fire,” and ancient Egyptian priests referred to it as “Ee Desher,” meaning “red.”

The land masses on Mars and Earth are very similar. Despite the fact that Mars occupies only 15% of the volume and 10% of the mass of the Earth, it has a land mass comparable to our planet as a consequence of the fact that water covers about 70% of the Earth's surface. At the same time, the surface gravity of Mars is about 37% of the gravity on Earth. This means that you could theoretically jump three times higher on Mars than on Earth.

Only 16 of 39 missions to Mars were successful. Since the Mars 1960A mission launched by the USSR in 1960, a total of 39 landers and rovers have been sent to Mars, but only 16 of these missions have been successful. In 2016, a probe was launched as part of the Russian-European ExoMars mission, the main goals of which will be to search for signs of life on Mars, study the surface and topography of the planet, and map potential environmental hazards for future manned missions to Mars.

Debris from Mars has been found on Earth. It is believed that traces of some of the Martian atmosphere were found in meteorites that bounced off the planet. After leaving Mars, these meteorites for a long time, for millions of years, flew around the solar system among other objects and space debris, but were captured by the gravity of our planet, fell into its atmosphere and crashed to the surface. The study of these materials allowed scientists to learn a lot about Mars even before space flights began.

In the recent past, people were sure that Mars was home to intelligent life. This was largely influenced by the discovery of straight lines and grooves on the surface of the Red Planet by Italian astronomer Giovanni Schiaparelli. He believed that such straight lines could not be created by nature and were the result of intelligent activity. However, it was later proven that this was nothing more than an optical illusion.

The highest planetary mountain known in the solar system is on Mars. It is called Olympus Mons (Mount Olympus) and rises 21 kilometers in height. It is believed that this is a volcano that was formed billions of years ago. Scientists have found quite a lot of evidence that the age of the object's volcanic lava is quite young, which may be evidence that Olympus may still be active. However, there is a mountain in the solar system to which Olympus is inferior in height - this is the central peak of Rheasilvia, located on the asteroid Vesta, whose height is 22 kilometers.

Dust storms occur on Mars - the most extensive in the solar system. This is due to the elliptical shape of the planet's orbit around the Sun. The orbital path is more elongated than many other planets and this oval orbital shape results in ferocious dust storms that cover the entire planet and can last for many months.

The Sun appears to be about half its visual Earth size when viewed from Mars. When Mars is closest to the Sun in its orbit, and its southern hemisphere faces the Sun, the planet experiences a very short but incredibly hot summer. At the same time, a short but cold winter sets in in the northern hemisphere. When the planet is farther from the Sun, and the northern hemisphere points towards it, Mars experiences a long and mild summer. In the southern hemisphere, a long winter sets in.

With the exception of Earth, scientists consider Mars the most suitable planet for life. Leading space agencies are planning a series of space missions over the next decade to find out whether there is potential for life on Mars and whether it is possible to build a colony on it.

Martians and aliens from Mars have been the leading candidates for extraterrestrials for quite a long time, making Mars one of the most popular planets in the solar system.

Mars is the only planet in the system, other than Earth, that has polar ice. Solid water has been discovered beneath the polar caps of Mars.

Just like on Earth, Mars has seasons, but they last twice as long. This is because Mars is tilted on its axis at about 25.19 degrees, which is close to Earth's axial tilt (22.5 degrees).

Mars has no magnetic field. Some scientists believe that it existed on the planet about 4 billion years ago.

The two moons of Mars, Phobos and Deimos, were described in the book Gulliver's Travels by Jonathan Swift. This was 151 years before they were discovered.

mathematical modeling and compared the results with the composition of the ancient Martian atmosphere trapped in an old meteorite. They concluded that 4 billion years ago there was a dense atmosphere, the surface pressure of which exceeded 0.5 bar (50,000 Pa).

This suggests that the process of disappearance of the atmosphere of Mars was most likely caused by the solar wind. It is he who is responsible for turning Mars into the cold desert world we know it as today.

When studying data obtained as a result of research expeditions to the Red Planet, scientists suggested that Mars once had a warm climate that supported the existence of oceans on its surface. This requires a dense atmosphere with a fairly pronounced greenhouse effect. However, modern Mars has a thin atmosphere, with a surface pressure of only 0.006 bar. This causes the planet to currently have a very cold climate compared to. It remained a big mystery when and how Mars lost its thick atmosphere.

Research method

The old meteorite at the disposal of scientists contains particles of the ancient Martian atmosphere. The researchers simulated the processes of change in the Martian atmosphere throughout its history under various conditions. By comparing the results with the isotopic composition of the meteorite-derived gas, the researchers calculated how dense Mars' atmosphere was at the time the gas became trapped in the meteorite.

Review of research results

The research team concluded that Mars had a dense atmosphere about 4 billion years ago. The air pressure at the surface of the planet at that time was at least 0.5 bar and possibly even higher. Mars had its own magnetic field, but lost it about 4 billion years ago. The result of the study shows that Mars is responsible for the transformation from a warm, wet world to a cold desert world, which began to destroy the planet's atmosphere.

Research prospects

NASA's MAVEN spacecraft is in orbit around Mars and continues to explore the processes that destroyed the Red Planet's atmosphere. The Japan Aerospace Exploration Agency (JAXA) plans to continue observing these processes using the Martian Moons eXploration (MMX) spacecraft. These missions will be able to explain how the dense atmosphere of ancient Mars, predicted in this paper, was lost over time.

Mars, the fourth planet farthest from the Sun, has been the object of close attention of world science for a long time. This planet is very similar to Earth, with one small but fateful exception - the atmosphere of Mars makes up no more than one percent of the volume of the Earth's atmosphere. The gaseous envelope of any planet is the determining factor that shapes its appearance and conditions on the surface. It is known that all the rocky worlds of the Solar System were formed under approximately the same conditions at a distance of 240 million kilometers from the Sun. If the conditions for the formation of Earth and Mars were almost the same, then why are these planets so different now?

It's all about size - Mars, formed from the same material as Earth, once had a liquid and hot metal core, like our planet. The proof is the many extinct volcanoes on But the “red planet” is much smaller than the Earth. This means that it cooled faster. When the liquid core finally cooled and solidified, the convection process ended, and with it the planet’s magnetic shield, the magnetosphere, disappeared. As a result, the planet remained defenseless against the destructive energy of the Sun, and the atmosphere of Mars was almost completely carried away by the solar wind (a gigantic stream of radioactive ionized particles). The “Red Planet” has turned into a lifeless, dull desert...

Now the atmosphere on Mars is a thin, rarefied gas shell, unable to withstand the penetration of the deadly gas that burns the surface of the planet. The thermal relaxation of Mars is several orders of magnitude less than that of, for example, Venus, whose atmosphere is much denser. The atmosphere of Mars, which has too low a heat capacity, produces more pronounced average daily wind speeds.

The composition of the atmosphere of Mars is characterized by a very high content (95%). The atmosphere also contains nitrogen (about 2.7%), argon (about 1.6%) and a small amount of oxygen (no more than 0.13%). The atmospheric pressure of Mars is 160 times higher than that at the surface of the planet. Unlike the Earth's atmosphere, the gas shell here has a pronounced variable nature, due to the fact that the polar caps of the planet, containing huge amounts of carbon dioxide, melt and freeze during one annual cycle.

According to data obtained from the Mars Express research spacecraft, the atmosphere of Mars contains some methane. The peculiarity of this gas is its rapid decomposition. This means that somewhere on the planet there must be a source of methane replenishment. There can be only two options here - either geological activity, traces of which have not yet been discovered, or the vital activity of microorganisms, which can change our understanding of the presence of centers of life in the Solar System.

A characteristic effect of the Martian atmosphere is dust storms that can rage for months. This dense air blanket of the planet consists mainly of carbon dioxide with minor inclusions of oxygen and water vapor. This lingering effect is due to the extremely low gravity of Mars, which allows even a super-rarefied atmosphere to lift billions of tons of dust from the surface and hold for a long time.

Atmosphere of Mars, like the atmosphere of Venus, consists mainly of carbon dioxide, although it is much thinner. After the discovery of methane in 2003, atmospheric research resumed with great excitement. The presence of methane may indirectly indicate the presence of life on Mars, although it is more likely that these are traces of the planet’s volcanic or hydrothermal activity.

The atmosphere is 96% carbon dioxide, 2.1% argon and 1.9% nitrogen. Traces of oxygen, methane, carbon monoxide and carbon dioxide, and small amounts of water vapor in the form of cold clouds were also found. The concentration of carbon dioxide on Mars is 23 times higher than on Earth. This makes it impossible for any life to exist on Mars. At least the life to which we are all accustomed on our native Earth.

Composition of the atmosphere of Mars.

The composition of the atmosphere, as well as its mass, fluctuates greatly during the Martian year. In winter, most of the carbon dioxide condenses in the polar caps, so the atmosphere becomes thinner. In summer, this part evaporates, and the density of the atmosphere increases.

But in both winter and summer, the density of the atmosphere is not so high as to smooth out temperature fluctuations. During one Martian day, temperature jumps exceed 100 o C. During the day it rises to +30 o C, and at night it drops to -80 o C. At the poles, the minimum temperature drops even lower, to -150 o C.

Atmospheric pressure on Mars is 600 Pa. For comparison, on Earth the atmospheric pressure is 101 Pa, and on Venus a huge 9.3 MPa. At Olympus Mons, the highest point on Mars, the atmospheric pressure is a measly 30 Pa. And at the deepest point of the planet, in the Hellas Plain, it reaches 1155 Pa.

Observations by the Mars Exploration Rover from the surface of Mars showed that despite the thin atmosphere, the air is quite dusty. The Martian sky is constantly colored with light brown and orange. Suspended particles of sand and dust rise to a height of 1.5 km. above the surface of the planet and, due to low pressure, settle for quite a long time.

History of the atmosphere

Scientists believe that the atmosphere of Mars has changed over the life of the planet. There is evidence that the planet had huge oceans several billion years ago. But at present, water can only exist in the form of steam or ice. Firstly, atmospheric pressure is capable of “holding” water in a liquid state only at the lowest points of the planet. And secondly, the average surface temperature is -63 o C, so water can only exist in a solid state.

However, early in its history, Mars had more favorable conditions. In early 2013, it was announced that the atmosphere of Mars was rich in oxygen about 4 billion years ago (). Among the possible causes of oxygen depletion in the atmosphere are the following:

1. Gradual destruction of the atmosphere by the solar wind.
2. A collision with a huge meteorite or comet that had catastrophic consequences for Mars.
3. The low gravity of Mars does not allow it to retain an atmosphere.

Potential for human use

How can a person use the atmosphere of Mars? This question is being asked more and more often, since the colonization of Mars no longer looks like an impossible fantasy dream. Yes, there are still more questions than answers. But issues need to be resolved one at a time, and not all at once.

Carbon dioxide from the atmosphere of Mars can be used to create rocket fuel for return to Earth. There are several options for using this rich volume of CO 2 , one of them is the Sabatier process. This chemical process is the reaction of carbon dioxide with hydrogen over a nickel catalyst. This reaction produces oxygen and methane.

Sabatier's reaction is already being "tried on" by scientists from NASA to recycle carbon dioxide on the International Space Station remaining after the astronauts breathe. Therefore, on Mars we may not need oxygen in the atmosphere - we will produce it ourselves.

Mars, like Venus, are Earth-like planets. They have a lot in common, but there are also differences. Scientists do not lose hope of finding life on Mars, as well as terraforming this “relative” of the Earth, albeit in the distant future. For the Red Planet this task seems simpler than for Venus. Unfortunately, Mars has a very weak magnetic field, which complicates the situation. The fact is that due to the almost complete absence of a magnetic field, the solar wind has a very strong effect on the planet’s atmosphere. It causes the dissipation of atmospheric gases, so that about 300 tons of atmospheric gases escape into space per day.

According to experts, it was the solar wind that caused the dispersion of about 90% of the Martian atmosphere over billions of years. As a result, the pressure at the surface of Mars is 0.7-1.155 kPa (1/110 of the Earth’s, such pressure on Earth can be seen by rising to a height of thirty kilometers from the surface).

The atmosphere on Mars consists mainly of carbon dioxide (95%) with small admixtures of nitrogen, argon, oxygen and some other gases. Unfortunately, the pressure and composition of the atmosphere on the Red Planet makes it impossible for terrestrial living organisms to breathe on the Red Planet. Probably, some microscopic organisms will be able to survive, but they will not be able to feel comfortable in such conditions.

The composition of the atmosphere is not such a problem. If the atmospheric pressure on Mars were half or a third of that on Earth, then colonists or marsonauts would be able to be on the surface of the planet at certain times of the day and year without spacesuits, using only a breathing apparatus. Many terrestrial organisms would feel more comfortable on Mars.

NASA believes that it is possible to increase atmospheric pressure on Earth's neighbor by protecting Mars from the solar wind. This protection is provided by a magnetic field. On Earth it exists thanks to the so-called hydrodynamic dynamo mechanism. In the liquid core of the planet, flows of electrically conductive substance (molten iron) constantly circulate, due to which electric currents are excited, which create magnetic fields. Internal flows in the earth's core are asymmetrical, which causes an increase in the magnetic field. The Earth's magnetosphere reliably protects the atmosphere from being blown away by the solar wind.

The dipole, according to the calculations of the authors of the project to create a magnetic shield for Mars, will generate a sufficiently strong magnetic field that will not allow the solar wind to reach the planet

Unfortunately for humans, there is no constant powerful magnetic field on Mars (and Venus), only weak traces are recorded. Thanks to the Mars Global Surveyor, it was possible to detect magnetic substance under the crust of Mars. NASA believes that these anomalies were formed under the influence of a once magnetic core and retained magnetic properties even after the planet itself lost its field.

Where to get a magnetic shield

NASA diagram shows how a magnetic shield would protect Mars from solar wind

The authors of the idea created several simulation models, each of which showed that after the launch of the magnetic shield, the pressure on Mars would reach half that of Earth. In particular, carbon dioxide at the poles of Mars will evaporate, turning into gas from the solid phase. Over time, the greenhouse effect will manifest itself, Mars will begin to warm up, the ice that is close to the surface of the planet in many places will melt and the planet will be covered with water. It is believed that such conditions existed on Mars about 3.5 billion years ago.

Of course, this is not a project of today, but perhaps in the next century people will be able to realize this idea and terraform Mars, creating a second home for themselves.