Encyclopedic YouTube
1 / 5
✪ Project DISCOVER-AQ - atmospheric research (NASA in Russian)
✪ NASA in Russian: 01/18/13 - video digest of NASA for the week
✪ NEGATIVE MASS [Science and technology news]
✪ Mars, 1968, science fiction film essay, directed by Pavel Klushantsev
✪ 5 Signs of Life On Mars - The Countdown #37
Subtitles
Studying
The atmosphere of Mars was discovered even before the flights of automatic interplanetary stations to the planet. Thanks to spectral analysis and oppositions of Mars with the Earth, which occur once every 3 years, astronomers already in the 19th century knew that it has a very homogeneous composition, more than 95% of which is carbon dioxide. When compared with 0.04% carbon dioxide in the Earth's atmosphere, it turns out that the mass of Martian atmospheric carbon dioxide exceeds the mass of Earth's by almost 12 times, so that when terraforming Mars, the carbon dioxide contribution to the greenhouse effect can create a climate comfortable for humans somewhat earlier than it is achieved pressure of 1 atmosphere, even taking into account the greater distance of Mars from the Sun.
Back in the early 1920s, the first measurements of the temperature of Mars were made using a thermometer placed at the focus of a reflecting telescope. Measurements by W. Lampland in 1922 gave an average surface temperature of Mars of 245 (−28 °C), E. Pettit and S. Nicholson in 1924 obtained 260 K (−13 °C). A lower value was obtained in 1960 by W. Sinton and J. Strong: 230 K (−43 °C). The first estimates of pressure - averaged - were obtained only in the 60s using ground-based IR spectroscopes: the pressure of 25 ± 15 hPa obtained from the Lorentz broadening of carbon dioxide lines meant that it was the main component of the atmosphere.
Wind speed can be determined by the Doppler shift of spectral lines. So, for this purpose, the shift of lines was measured in the millimeter and submillimeter range, and measurements with an interferometer make it possible to obtain the velocity distribution in an entire layer of large thickness.
The most detailed and accurate data on air and surface temperature, pressure, relative humidity and wind speed are continuously measured by the Rover Environmental Monitoring Station (REMS) instrumentation aboard the Curiosity rover operating in Gale Crater since 2012. And the MAVEN device, which has been in orbit around Mars since 2014, is specifically designed for a detailed study of the upper layers of the atmosphere, their interaction with solar wind particles and, in particular, scattering dynamics.
A number of processes that are complex or not yet possible for direct observation are subject only to theoretical modeling, but it is also an important research method.
Atmospheric structure
In general, the atmosphere of Mars is divided into lower and upper; the latter is considered to be the region above 80 km above the surface, where ionization and dissociation processes play an active role. A section is devoted to its study, which is commonly called aeronomy. Usually, when people talk about the atmosphere of Mars, they mean the lower atmosphere.
Also, some researchers distinguish two large shells - the homosphere and the heterosphere. In the homosphere, the chemical composition does not depend on altitude, since the processes of heat and moisture transfer in the atmosphere and their vertical exchange are entirely determined by turbulent mixing. Since molecular diffusion in the atmosphere is inversely proportional to its density, from a certain level this process becomes predominant and is the main feature of the upper shell - the heterosphere, where molecular diffusion separation occurs. The interface between these shells, which is located at altitudes between 120 and 140 km, is called the turbopause.
Lower atmosphere
Stretches from the surface to a height of 20-30 km troposphere, where the temperature decreases with height. The upper boundary of the troposphere varies depending on the time of year (the temperature gradient in the tropopause varies from 1 to 3 degrees/km with an average value of 2.5 degrees/km).
Above the tropopause is the isothermal region of the atmosphere - stratomesosphere, stretching to an altitude of 100 km. The average temperature of the stratomesosphere is exceptionally low and amounts to - 133°C. Unlike the Earth, where the stratosphere contains predominantly all atmospheric ozone, on Mars its concentration is negligible (it is distributed from altitudes of 50 - 60 km to the surface itself, where it is maximum).
Upper atmosphere
Above the stratomesosphere extends the upper layer of the atmosphere - thermosphere. It is characterized by an increase in temperature with height up to a maximum value (200-350 K), after which it remains constant until the upper limit (200 km). The presence of atomic oxygen was recorded in this layer; its density at an altitude of 200 km reaches 5-6⋅10 7 cm −3. The presence of a layer dominated by atomic oxygen (as well as the fact that the main neutral component is carbon dioxide) unites the atmosphere of Mars with that of Venus.
Ionosphere- an area with a high degree of ionization - located in the altitude range from approximately 80-100 to about 500-600 km. The ion content is minimal at night and maximum during the day, when the main layer is formed at an altitude of 120-140 km due to photoionization of carbon dioxide extreme ultraviolet radiation from the Sun CO 2 + hν → CO 2 + + e - , as well as reactions between ions and neutral substances CO 2 + + O → O 2 + + CO and O + + CO 2 → O 2 + + CO. The concentration of ions, of which 90% O 2 + and 10% CO 2 +, reaches 10 5 per cubic centimeter (in other areas of the ionosphere it is 1-2 orders of magnitude lower). It is noteworthy that O 2 + ions predominate in the almost complete absence of molecular oxygen itself in the atmosphere of Mars. The secondary layer is formed in the region of 110-115 km due to soft X-ray radiation and knocked out fast electrons. At an altitude of 80-100 km, some researchers identify a third layer, sometimes manifested under the influence of cosmic dust particles that introduce metal ions Fe +, Mg +, Na + into the atmosphere. However, later it was not only confirmed the appearance of the latter (and almost throughout the entire volume of the upper atmosphere) due to the ablation of matter from meteorites and other cosmic bodies entering the atmosphere of Mars, but also their generally constant presence. Moreover, due to the absence of a magnetic field on Mars, their distribution and behavior differ significantly from what is observed in the Earth’s atmosphere. Above the main maximum, other additional layers may appear due to interaction with the solar wind. Thus, the layer of O + ions is most pronounced at an altitude of 225 km. In addition to the three main types of ions (O 2 +, CO 2 and O +), relatively recently H 2 +, H 3 +, He +, C +, CH +, N +, NH +, OH +, H 2 were also registered O + , H 3 O + , N 2 + /CO + , HCO + /HOC + /N 2 H + , NO + , HNO + , HO 2 + , Ar + , ArH + , Ne + , CO 2 ++ and HCO2+. Above 400 km, some authors identify an “ionopause”, but there is no consensus on this matter yet.
As for the plasma temperature, near the main maximum the ion temperature is 150 K, increasing to 210 K at an altitude of 175 km. Higher up, the thermodynamic equilibrium of the ions with the neutral gas is significantly disrupted, and their temperature rises sharply to 1000 K at an altitude of 250 km. The electron temperature can be several thousand Kelvin, apparently due to the magnetic field in the ionosphere, and it increases with increasing zenith angle of the Sun and is not the same in the northern and southern hemispheres, which may be due to the asymmetry of the residual magnetic field of the Martian crust. In general, one can even distinguish three populations of high-energy electrons with different temperature profiles. The magnetic field also affects the horizontal distribution of ions: streams of high-energy particles are formed above magnetic anomalies, twisting along the field lines, which increases the intensity of ionization, and an increased ion density and local structures are observed.
At an altitude of 200-230 km there is the upper boundary of the thermosphere - the exobase, above which it begins from approximately an altitude of 250 km exosphere Mars. It consists of light substances - hydrogen, carbon, oxygen - that appear as a result of photochemical reactions in the underlying ionosphere, for example, dissociative recombination of O 2 + with electrons. A continuous supply of atomic hydrogen to the upper atmosphere of Mars occurs due to the photodissociation of water vapor at the Martian surface. Because the concentration of hydrogen decreases very slowly with altitude, this element is a major component of the outermost layers of the planet's atmosphere and forms a hydrogen corona, extending over a distance of about 20,000 km, although there is no strict boundary and particles from this region simply gradually disperse into the surrounding space.
In the atmosphere of Mars it is also sometimes released chemosphere- a layer where photochemical reactions occur, and since, due to the absence of an ozone screen, like the Earth, ultraviolet radiation reaches the very surface of the planet, they are possible even there. The Martian chemosphere extends from the surface to an altitude of about 120 km.
Chemical composition of the lower atmosphere
Despite the strong rarefaction of the Martian atmosphere, the concentration of carbon dioxide in it is approximately 23 times higher than in the earth's atmosphere.
- Nitrogen (2.7%) is currently actively dissipating into space. In the form of a diatomic molecule, nitrogen is stably held by the planet's gravity, but is split into single atoms by solar radiation, easily leaving the atmosphere.
- Argon (1.6%) is represented by the heavy isotope argon-40, which is relatively resistant to dissipation. Light 36 Ar and 38 Ar are present only in parts per million
- Other noble gases: neon, krypton, xenon (ppm)
- Carbon oxide (CO) is a product of photodissociation of CO 2 and accounts for 7.5⋅10 -4 of the concentration of the latter - this is an inexplicably small value, since the reverse reaction CO + O + M → CO 2 + M is prohibited, and much more would have to accumulate CO. Various theories have been proposed on how carbon monoxide can still be oxidized to carbon dioxide, but they all have one or another drawback.
- Molecular oxygen (O 2) - appears as a result of photodissociation of both CO 2 and H 2 O in the upper atmosphere of Mars. In this case, oxygen diffuses into lower layers of the atmosphere, where its concentration reaches 1.3⋅10 -3 of the near-surface concentration of CO 2 . Like Ar, CO and N 2, it is a non-condensable substance on Mars, so its concentration also undergoes seasonal variations. In the upper atmosphere, at an altitude of 90-130 km, the O 2 content (fraction relative to CO 2) is 3-4 times higher than the corresponding value for the lower atmosphere and averages 4⋅10 -3, varying in the range from 3.1⋅10 -3 to 5.8⋅10 -3. In ancient times, the atmosphere of Mars contained, however, a larger amount of oxygen, comparable to its share on the young Earth. Oxygen, even in the form of individual atoms, no longer dissipates as actively as nitrogen, due to its greater atomic weight, which allows it to accumulate.
- Ozone - its amount varies greatly depending on surface temperature: it is minimum during the equinox at all latitudes and maximum at the pole, where it is winter, in addition, it is inversely proportional to the concentration of water vapor. There is one pronounced ozone layer at an altitude of about 30 km and another between 30 and 60 km.
- Water. The H 2 O content in the atmosphere of Mars is approximately 100-200 times less than in the atmosphere of the driest regions of the Earth, and amounts to an average of 10-20 microns of the deposited column of water. Water vapor concentration undergoes significant seasonal and diurnal variations. The degree of saturation of the air with water vapor is inversely proportional to the content of dust particles, which are centers of condensation, and in certain areas (in winter, at an altitude of 20-50 km) vapor was recorded, the pressure of which exceeds the pressure of saturated vapor by 10 times - much more than in the earth’s atmosphere .
- Methane. Since 2003, there have been reports of registration of methane emissions of unknown origin, but none of them can be considered reliable due to certain shortcomings of registration methods. In this case, we are talking about extremely small values - 0.7 ppbv (upper limit - 1.3 ppbv) as a background value and 7 ppbv for episodic bursts, which is on the verge of solvability. Since, along with this, information was also published about the absence of CH 4 confirmed by other studies, this may indicate some intermittent source of methane, as well as the existence of some mechanism for its rapid destruction, while the duration of photochemical destruction of this substance is estimated at 300 years. The discussion on this issue is currently open, and it is of particular interest in the context of astrobiology, due to the fact that on Earth this substance is of biogenic origin.
- Traces of some organic compounds. The most important are the upper limits on H 2 CO, HCl and SO 2, which indicate the absence, respectively, of reactions involving chlorine, as well as volcanic activity, in particular, the non-volcanic origin of methane, if its existence is confirmed.
The composition and pressure of the atmosphere of Mars make it impossible for humans and other terrestrial organisms to breathe. To work on the surface of the planet, a spacesuit is required, although not as bulky and protected as for the Moon and outer space. The atmosphere of Mars itself is not toxic and consists of chemically inert gases. The atmosphere somewhat slows down meteorite bodies, so there are fewer craters on Mars than on the Moon and they are less deep. Micrometeorites burn up completely without reaching the surface.
Water, clouds and precipitation
Low density does not prevent the atmosphere from forming large-scale phenomena that affect climate.
There is no more than a thousandth of a percent of water vapor in the Martian atmosphere, however, according to the results of recent (2013) studies, this is still more than previously thought, and more than in the upper layers of the Earth's atmosphere, and at low pressure and temperature it is in in a state close to saturation, so it often gathers in clouds. As a rule, water clouds form at altitudes of 10-30 km above the surface. They are concentrated mainly at the equator and are observed almost throughout the year. Clouds observed at high levels of the atmosphere (more than 20 km) are formed as a result of CO 2 condensation. The same process is responsible for the formation of low (at an altitude of less than 10 km) clouds in the polar regions in winter, when the atmospheric temperature drops below the freezing point of CO 2 (-126 ° C); in summer, similar thin formations of ice H 2 O are formed
One of the interesting and rare atmospheric phenomena on Mars was discovered (“Viking-1”) when photographing the northern polar region in 1978. These are cyclonic structures, clearly identified in photographs by vortex-like cloud systems with counterclockwise circulation. They were discovered in the latitude zone 65-80° N. w. during the “warm” period of the year, from spring to early autumn, when the polar front sets up here. Its occurrence is due to the sharp contrast in surface temperatures that exists at this time of year between the edge of the ice cap and the surrounding plains. The wave movements of air masses associated with such a front lead to the appearance of cyclonic vortices so familiar to us on Earth. The vortex cloud systems discovered on Mars range in size from 200 to 500 km, their movement speed is about 5 km/h, and the wind speed at the periphery of these systems is about 20 m/s. The duration of existence of an individual cyclonic eddy ranges from 3 to 6 days. Temperatures in the central part of Martian cyclones indicate that the clouds consist of water ice crystals.
Snow has indeed been observed more than once. So, in the winter of 1979, a thin layer of snow fell in the Viking-2 landing area, which remained for several months.
Dust storms and dust devils
A characteristic feature of the atmosphere of Mars is the constant presence of dust; According to spectral measurements, the size of dust particles is estimated at 1.5 μm. Low gravity allows even thin air currents to raise huge clouds of dust to a height of up to 50 km. And winds, which are one of the manifestations of temperature differences, often blow over the surface of the planet (especially in late spring - early summer in the southern hemisphere, when the temperature difference between the hemispheres is especially sharp), and their speed reaches 100 m/s. In this way, extensive dust storms are formed, long observed in the form of individual yellow clouds, and sometimes in the form of a continuous yellow shroud covering the entire planet. Most often, dust storms occur near the polar caps; their duration can reach 50-100 days. A faint yellow haze in the atmosphere is usually observed after large dust storms and is easily detected by photometric and polarimetric methods.
Dust storms, clearly visible in images taken from orbital vehicles, turned out to be barely noticeable when photographed from landers. The passage of dust storms in the landing sites of these space stations was recorded only by a sharp change in temperature, pressure and a very slight darkening of the general background of the sky. The layer of dust that settled after the storm in the vicinity of the Viking landing sites amounted to only a few micrometers. All this indicates a rather low bearing capacity of the Martian atmosphere.
From September 1971 to January 1972, a global dust storm occurred on Mars, which even prevented photography of the surface from the Mariner 9 probe. The mass of dust in the atmospheric column (with an optical depth of 0.1 to 10), estimated during this period, ranged from 7.8⋅10 -5 to 1.66⋅10 -3 g/cm 2 . Thus, the total weight of dust particles in the atmosphere of Mars during the period of global dust storms can reach up to 10 8 - 10 9 tons, which is comparable to the total amount of dust in the Earth's atmosphere.
The aurora was first recorded by the SPICAM UV spectrometer on board the Mars Express spacecraft. Then it was observed several times by the MAVEN apparatus, for example, in March 2015, and in September 2017, a much more powerful event was recorded by the Radiation Assessment Detector (RAD) on the Curiosity rover. Analysis of data from the MAVEN apparatus also revealed aurora of a fundamentally different type - diffuse, which occur at low latitudes, in areas not tied to magnetic field anomalies and caused by the penetration of particles with very high energy, about 200 keV, into the atmosphere.
In addition, the extreme ultraviolet radiation of the Sun causes the so-called intrinsic glow of the atmosphere (English airglow).
Registration of optical transitions during auroras and their own glow provides important information about the composition of the upper atmosphere, its temperature and dynamics. Thus, studying the γ- and δ-bands of nitric oxide emission at night helps characterize the circulation between illuminated and unlit areas. And the registration of radiation at a frequency of 130.4 nm during its own glow helped to identify the presence of high-temperature atomic oxygen, which was an important step in understanding the behavior of atmospheric exospheres and coronas in general.
Color
The dust particles that fill the atmosphere of Mars are composed mainly of iron oxide, and this gives it a reddish-red hue.
According to measurements, the atmosphere has an optical thickness of 0.9 - this means that only 40% of the incident solar radiation reaches the surface of Mars through its atmosphere, and the remaining 60% is absorbed by dust hanging in the air. Without it, the Martian skies would have approximately the same color as the Earth's sky at an altitude of 35 kilometers. It should be noted that in this case the human eye would adapt to these colors, and the white balance would automatically adjust so that the sky would be seen the same as under terrestrial lighting conditions.
The color of the sky is very heterogeneous, and in the absence of clouds or dust storms, from relatively light on the horizon it darkens sharply and gradually towards the zenith. In a relatively calm and windless season, when there is less dust, the sky can be completely black at the zenith.
Nevertheless, thanks to images from Mars rovers, it became known that at sunset and sunrise around the Sun the sky turns blue. The reason for this is RAYLEIGH scattering - light is scattered on gas particles and colors the sky, but if on a Martian day the effect is weak and invisible to the naked eye due to the thin atmosphere and dust, then at sunset the sun shines through a much thicker layer of air, due to which blue and violet begin to scatter components. The same mechanism is responsible for the blue sky on Earth during the day and yellow-orange at sunset. [ ]
Panorama of the Rocknest Dunes, compiled from images from the Curiosity rover.
Changes
Changes in the upper layers of the atmosphere are quite complex, since they are connected with each other and with the underlying layers. Atmospheric waves and tides propagating upward can have a significant impact on the structure and dynamics of the thermosphere and, as a consequence, the ionosphere, for example, the height of the upper boundary of the ionosphere. During dust storms in the lower atmosphere, its transparency decreases, it heats up and expands. Then the density of the thermosphere increases - it can vary even by an order of magnitude - and the height of the maximum electron concentration can rise by up to 30 km. Changes in the upper atmosphere caused by dust storms can be global, affecting areas up to 160 km above the planet's surface. The response of the upper atmosphere to these phenomena takes several days, and it takes much longer to return to its previous state - several months. Another manifestation of the relationship between the upper and lower atmosphere is that water vapor, which, as it turns out, is supersaturated in the lower atmosphere, can undergo photodissociation into lighter components H and O, which increase the density of the exosphere and the intensity of water loss from the atmosphere of Mars. External factors causing changes in the upper atmosphere are extreme ultraviolet and soft X-ray radiation from the Sun, solar wind particles, cosmic dust and larger bodies such as meteorites. The task is complicated by the fact that their impact is, as a rule, random, and its intensity and duration cannot be predicted, and cyclical processes associated with changes in the time of day, season, as well as the solar cycle are superimposed on episodic phenomena. At the moment, at best, there is accumulated statistics of events on the dynamics of atmospheric parameters, but a theoretical description of the patterns has not yet been completed. A direct proportionality has been definitely established between the concentration of plasma particles in the ionosphere and solar activity. This is confirmed by the fact that a similar pattern was actually recorded based on the results of observations in 2007-2009 for the Earth’s ionosphere, despite the fundamental difference in the magnetic field of these planets, which directly affects the ionosphere. And ejections of particles from the solar corona, causing a change in solar wind pressure, also entail a characteristic compression of the magnetosphere and ionosphere: the maximum plasma density drops to 90 km.
Daily fluctuations
Despite its rarefaction, the atmosphere nevertheless reacts to changes in the flow of solar heat more slowly than the surface of the planet. Thus, in the morning, the temperature varies greatly with altitude: a difference of 20° was recorded at an altitude of 25 cm to 1 m above the surface of the planet. As the Sun rises, cold air heats up from the surface and rises upward in a characteristic vortex, lifting dust into the air - this is how dust devils are formed. In the near-surface layer (up to 500 m in height) there is a temperature inversion. After the atmosphere has already warmed up by noon, this effect is no longer observed. The maximum is reached at about 2 o'clock in the afternoon. The surface then cools faster than the atmosphere, and a reverse temperature gradient is observed. Before sunset, the temperature again decreases with altitude.
The change of day and night also affects the upper atmosphere. First of all, at night, ionization by solar radiation stops, but the plasma continues to be replenished for the first time after sunset due to the flow from the day side, and then is formed due to the impacts of electrons moving down along the magnetic field lines (the so-called electron intrusion) - then the maximum observed at an altitude of 130-170 km. Therefore, the density of electrons and ions on the night side is much lower and is characterized by a complex profile, which also depends on the local magnetic field and changes in a non-trivial way, the pattern of which is not yet fully understood and described theoretically. Throughout the day, the state of the ionosphere also changes depending on the zenith angle of the Sun.
Annual cycle
As on Earth, on Mars there is a change of seasons due to the inclination of the rotation axis to the orbital plane, so in winter the polar cap grows in the northern hemisphere, and almost disappears in the southern hemisphere, and after six months the hemispheres change places. Moreover, due to the rather large eccentricity of the planet’s orbit at perihelion (winter solstice in the northern hemisphere), it receives up to 40% more solar radiation than at aphelion, and in the northern hemisphere winters are short and relatively moderate, and summers are long but cool, in in the south, on the contrary, summers are short and relatively warm, and winters are long and cold. In this regard, the southern cap in winter grows to half the pole-equator distance, and the northern one - only to a third. When summer begins at one of the poles, carbon dioxide from the corresponding polar cap evaporates and enters the atmosphere; the winds carry it to the opposite cap, where it freezes again. This creates a cycle of carbon dioxide, which, along with the different sizes of the polar caps, causes the pressure of the atmosphere of Mars to change as it orbits the Sun. Due to the fact that in winter up to 20-30% of the entire atmosphere freezes in the polar cap, the pressure in the corresponding area drops accordingly.
The concentration of water vapor also undergoes seasonal variations (as well as daily ones) - they are in the range of 1-100 microns. Thus, in winter the atmosphere is almost “dry”. Water vapor appears in it in the spring, and by mid-summer its amount reaches a maximum, following changes in surface temperature. During the summer-autumn period, water vapor is gradually redistributed, and its maximum content moves from the northern polar region to the equatorial latitudes. At the same time, the total global vapor content in the atmosphere (according to Viking 1 data) remains approximately constant and is equivalent to 1.3 km 3 of ice. The maximum H 2 O content (100 µm of precipitated water equal to 0.2 volume %) was recorded in the summer over the dark region encircling the northern remnant polar cap - at this time of year the atmosphere above the polar cap ice is usually close to saturation.
In the spring-summer period in the southern hemisphere, when dust storms are most actively formed, daily or semi-diurnal atmospheric tides are observed - an increase in pressure at the surface and thermal expansion of the atmosphere in response to its heating.
The change of seasons also affects the upper atmosphere - both the neutral component (thermosphere) and the plasma (ionosphere), and this factor must be taken into account together with the solar cycle, and this complicates the task of describing the dynamics of the upper atmosphere.
Long-term changes
See also
Notes
- Williams, David R. Mars Fact Sheet (undefined) . National Space Science Data Center. NASA (September 1, 2004). Retrieved September 28, 2017.
- N. Mangold, D. Baratoux, O. Witasse, T. Encrenaz, C. Sotin. Mars: a small terrestrial planet: [English] ]// The Astronomy and Astrophysics Review. - 2016. - T. 24, No. 1 (16 December). - P. 15. - DOI:10.1007/s00159-016-0099-5.
- Atmosphere of Mars (undefined) . UNIVERSE-PLANET // PORTAL TO ANOTHER DIMENSION
- Mars is a red star. Description of the area. Atmosphere and climate (undefined) . galspace.ru - Project "Exploration of the Solar System". Retrieved September 29, 2017.
- (English) Out of Thin Martian Air Astrobiology Magazine, Michael Schirber, 22 August 2011.
- Maxim Zabolotsky. General information about the atmosphere of Mars (undefined) . Spacegid.com(21.09.2013). Retrieved October 20, 2017.
- Mars Pathfinder - Science Results - Atmospheric and Meteorological Properties (undefined) . nasa.gov. Retrieved April 20, 2017.
- J. L. Fox, A. Dalgarno. Ionization, luminosity, and heating of the upper atmosphere of Mars: [English] ]// J Geophys Res. - 1979. - T. 84, issue. A12 (1 December). - pp. 7315–7333. -
Each planet differs from the others in a number of characteristics. People compare other found planets with the one they know well, but not perfectly - this is planet Earth. After all, this is logical, life could appear on our planet, which means that if you look for a planet similar to ours, then it will also be possible to find life there. Because of these comparisons, the planets have their own distinctive features. For example, Saturn has beautiful rings, which is why Saturn is called the most beautiful planet in the solar system. Jupiter is the largest planet in the solar system and this is a feature of Jupiter. So what are the features of Mars? This is what this article is about.
Mars, like many planets in the solar system, has satellites. In total, Mars has two satellites: Phobos and Deimos. The satellites got their names from the Greeks. Phobos and Deimos were the sons of Ares (Mars) and were always close to their father, just as these two satellites were always close to Mars. In translation, “Phobos” means “fear”, and “Deimos” means “horror”.
Phobos is a satellite whose orbit is very close to the planet. It is the closest satellite to a planet in the entire solar system. The distance from the surface of Mars to Phobos is 9380 kilometers. The satellite orbits Mars with a frequency of 7 hours 40 minutes. It turns out that Phobos manages to make a little over three revolutions around Mars, while Mars itself makes one revolution around its axis.
Deimos is the smallest moon in the solar system. The dimensions of the satellite are 15x12.4x10.8 km. And the distance from the satellite to the surface of the planet is 23,450 thousand km. Deimos's orbital period around Mars is 30 hours and 20 minutes, which is slightly longer than the time it takes the planet to rotate on its axis. If you are on Mars, Phobos will rise in the west and set in the east, while making three revolutions per day, while Deimos, on the contrary, rises in the east and sets in the west, while making only one revolution around the planet.
Features of Mars and its Atmosphere
One of the main features of Mars is that it was created. The atmosphere on Mars is quite interesting. Now the atmosphere on Mars is very thin, it is possible that in the future Mars will completely lose its atmosphere. The peculiarities of the atmosphere of Mars are that once upon a time Mars had the same atmosphere and air as on our home planet. But during its evolution, the Red Planet lost almost all of its atmosphere. Now the pressure of the atmosphere of the Red Planet is only 1% of the pressure of our planet. The peculiarity of the atmosphere of Mars is also that even with a third of the gravity of the planet relative to the Earth, Mars can raise huge dust storms, lifting tons of sand and soil into the air. Dust storms have already spoiled the nerves of our astronomers more than once; since dust storms can be very extensive, observing Mars from Earth becomes impossible. Sometimes such storms can even last for months, which greatly spoils the process of studying the planet. But the exploration of the planet Mars does not stop there. There are robots on the surface of Mars that do not stop exploring the planet.
The atmospheric features of the planet Mars also mean that scientists’ guesses about the color of the Martian sky have been refuted. Scientists believed that the sky on Mars should be black, but images taken by the space station from the planet disproved this theory. The sky on Mars is not black at all, it is pink, thanks to particles of sand and dust that are in the air and absorb 40% of sunlight, which creates the effect of a pink sky on Mars.
Features of the temperature of Mars
Measurements of the temperature of Mars began relatively long ago. It all started with Lampland's measurements in 1922. Then the measurements indicated that the average temperature on Mars was -28º C. Later, in the 50s and 60s, some knowledge about the temperature regime of the planet was accumulated, which was carried out from the 20s to the 60s. From these measurements it turns out that during the day at the equator of the planet the temperature can reach +27º C, but by the evening it will drop to zero, and by the morning it becomes -50º C. The temperature at the poles ranges from +10º C, during the polar day, and to very low temperatures during the polar night.
Relief features of Mars
The surface of Mars, like other planets that do not have an atmosphere, is scarred by various craters from the falls of space objects. Craters are small (5 km in diameter) and large (from 50 to 70 km in diameter). Due to the lack of its atmosphere, Mars was subject to meteor showers. But the planet's surface contains more than just craters. Previously, people believed that there was never water on Mars, but observations of the planet's surface tell a different story. The surface of Mars has channels and even small depressions that resemble water deposits. This suggests that there was water on Mars, but for many reasons it disappeared. Now it’s difficult to say what needs to be done so that water appears on Mars again and we can watch the resurrection of the planet.
There are also volcanoes on the Red Planet. The most famous volcano is Olympus. This volcano is known to all those interested in Mars. This volcano is the largest hill not only on Mars, but also in the solar system, this is another feature of this planet. If you stand at the foot of the Olympus volcano, it will be impossible to see the edge of this volcano. This volcano is so large that its edges go beyond the horizon and it seems that Olympus is endless.
Features of the Magnetic Field of Mars
This is perhaps the last interesting feature of this planet. The magnetic field is the protector of the planet, which repels all electrical charges moving towards the planet and pushes them away from their original trajectory. The magnetic field is completely dependent on the planet's core. The core on Mars is almost motionless and, therefore, the planet's magnetic field is very weak. The action of the Magnetic field is very interesting, it is not global, as on our planet, but has zones in which it is more active, and in other zones it may not be at all.
Thus, the planet, which seems so ordinary to us, has a whole set of its own features, some of which are leading in our Solar System. Mars is not as simple a planet as you might think at first glance.
Like any large planet, Mars has an atmosphere. It consists of a gaseous substance that the planet holds due to gravity. However, the air on Mars is very different from that on Earth.
General information about the atmosphere of Mars
The atmosphere of Mars is much thinner than that of Earth. Its height is 11 km, which is approximately 9-10% of the earth's. This is caused by the weak gravitational force on the planet, unable to hold a wider layer of gas. The small thickness and density of the atmosphere causes such air phenomena that cannot be found on Earth.
Chemically, the atmosphere consists mainly of carbon dioxide.
The density of the atmosphere is also very low: more than 61 times less than the average density on Earth.
Because of its properties, the atmosphere is constantly exposed to the solar wind, losing matter and dissipating faster than on other planets. This process is called dissipation. This is due to the fact that the planet Mars does not have a magnetic field.
Atmospheric structure
Even though it is thin, the Martian atmosphere is heterogeneous and has a layered structure. Its structure looks like this:
● Below all the layers is the troposphere. It occupies the entire space from the surface to 20-30 km. The temperature here decreases uniformly as it rises. The upper boundary of the troposphere is not fixed and changes its position throughout the year.
● Above is the stratomesosphere. The temperature in this part is approximately the same and equal to –133 °C. It continues up to an altitude of 100 km above the surface, where the entire lower atmosphere ends along with it.
● Everything that is located above (up to the boundary where space begins) is called the upper atmosphere. Another name for this layer is the thermosphere, and its average temperature is from 200 to 350 K.
● Inside it is the ionosphere, which, as the name suggests, is characterized by a high level of ionization resulting from solar radiation. It begins approximately in the same place as the entire upper part and has a length of approximately 400 km.
● At an altitude of about 230 km, the thermosphere ends. Its last layer is called ecobase.
● Belonging to neither the lower nor the upper atmosphere, the chemosphere is defined, in which chemical reactions initiated by light occur. Because Mars lacks any equivalent to Earth's Ozone layer, this layer begins at surface level. And it ends at an altitude of 120 km.
So, the surface of Mars is covered with a fairly thin and rarefied atmosphere, which, however, has a relatively complex structure. In total, the atmosphere of Mars consists of seven layers, but this number may vary in different sources, since scientists have not yet agreed on the nature of some layers.
Do not think that the layered structure indicates staticity. The atmosphere of Mars is also prone to change, like the earth's: it contains both general circulation and private movements of air flows.
Atmospheric composition
The chemical composition of the atmosphere of Mars is very different from that of Earth. The air on Mars consists of the following gases:
● The atmosphere of the planet Mars is based on carbon dioxide. It occupies approximately 95% of its volume. This is the only heavy gas that the planet can hold.
● Most carbon dioxide is CO2, but carbon monoxide CO also makes up some of it. This fraction is unusually small and has led scientists to theorize about why CO does not accumulate.
● Nitrogen N2. It makes up a very small part of the atmosphere - only 2.7%. However, it can only linger in the atmosphere in the form of a double molecule. Radiation from the Sun continually breaks down atmospheric nitrogen into atoms, after which it dissipates.
● Argon occupies 1.6% and is represented mainly by the heavy isotope argon-40.
● Oxygen is also present on Mars, but it is contained mainly in the upper atmosphere and appears during the decomposition of other substances, from where it then passes into the lower layers. Because of this, at an altitude of approximately 110 km and above there is 3-4 times more O2 than below this level. They can't breathe.
● Ozone is the most uncertain gas in the Martian atmosphere. Its content depends on the air temperature, and therefore on the time of year, latitude and hemisphere.
● Methane on Mars, despite its low content in the atmosphere, is one of the most mysterious gases on the planet. It can have several sources, but the most relevant are two: the influence of temperatures (for example, in volcanoes) and the processing of substances by bacteria and ruminants, after which bacterial methane is formed. The latter is of particular interest for astrobiology - it is what is sought on potentially inhabited planets in order to prove that there is life on them. It is unknown what methane appearing in bursts on Mars may indicate.
● Organic compounds such as H2CO, HCl and SO2 are also found in the atmosphere of Mars. They can clarify the issue discussed above, since their presence indicates the absence of volcanic activity - and therefore thermogenic methane.
● Water. Even though its content is several hundred times less than in the driest regions of the Earth, it is still present.
● It is also worth mentioning that the atmosphere of Mars is filled with tiny dust particles (mainly iron oxide). They make the atmosphere reddish-orange from the outside, and they are also responsible for the colors of the sky, the opposite of those on Earth: the daytime skies on Mars are yellow-brown, at sunset and dawn they turn pink, and around the Sun they turn blue.
Clouds
The atmosphere of the Red Planet is capable of forming the same phenomena as the earth's. For example, there are clouds on Mars.
There is very little vaporous water in the atmosphere of the planet Mars, but still enough for the appearance of clouds. Most often they are located at an altitude of one to three tens of kilometers above the surface. Concentrated water vapor collects in clouds mainly at the equator - there they can be observed all year round.
In addition, a cloud on Mars can also produce CO2. Usually it is located above the water ones (at an altitude of about 20 km).
There are also fogs on Mars. Most often - in lowlands and craters, at night.
One day, vortex-like systems of clouds were discovered in a photograph of the Martian atmosphere. This was evidence of a more complex climatic phenomenon - a cyclone. On Earth this is a common phenomenon, but on other planets it is quite unusual. Nothing more is known about Martian cyclones yet.
There is no ordinary rain on Mars, but among natural phenomena, virga is sometimes observed - drops or snow that evaporate in the air before reaching the ground.
Greenhouse effect
The conversation about the greenhouse effect on Mars always comes in the context of a discussion of liquid water that once existed on it. “Rivers” on the surface are already talking about this, but this was not enough for scientists, and they decided to find what allowed liquid H2O to appear.
When Mars was a young planet, its volcanoes were extremely active. Each volcanic explosion on Mars released carbon dioxide and methane, which decomposed when exposed to sunlight, producing hydrogen and creating the “hydrogen greenhouse effect.” At some point, the concentration of the latter gas increased so much that it allowed the existence of lakes, rivers and even entire oceans of water. However, over time, the planet's atmosphere thinned and could no longer provide conditions in which water would remain liquid. Currently, only water vapor or ice can be found on Mars. The transition from one state of aggregation to another occurs through sublimation, bypassing the liquid stage. This can be called a unique feature in the history of the atmosphere of Mars, since this has not yet happened on any other planet. However, this is only a scientific theory.
Pressure
On average, atmospheric pressure on Mars is 4.5 mmHg or 600 Pascals. This is one 169th of the average pressure on Earth. Such pressure makes it impossible for a person to survive on the surface without a spacesuit. People who find themselves on the open surface of the planet Mars without protection face instant death. The reason for this is the existence of the so-called Armstrong limit - the pressure level at which water boils at normal human body temperature. The atmospheric pressure on the surface of Mars is significantly below this limit.
Dust devils
Dust storms that regularly occur on Mars are a feature of this planet. They are caused by storms on Mars, in which wind speeds reach 100 km/h. The air collects dust hanging in the atmosphere to a height of up to 50 km. This gives rise to those same dust storms on Mars. Most often they occur in the polar regions and rage for 1.5 - 3 months. Sandstorms also occur on Mars in a similar way. The only difference is that this time larger particles that have settled on the surface - sand - rise into the air.
However, if there is wind on Mars, then there must also be dangerous air phenomena that it causes. For example, tornadoes. They, like storms, raise sand and dust into the air, but extend hundreds of meters in width and kilometers in height and seem much more dangerous (even though their speed is three times lower than that of storms - only 30 km /h). Due to the same low density of the atmosphere, tornadoes on Mars are more like tornadoes. Their second name is dust devils. From orbit you can see how they leave black swirling trails on the light sandy surface.
Radiation
Radiation on Mars poses no less danger to people than dust or low pressure. There are two reasons for this: the weakness and rarefaction of the atmosphere and the absence of a magnetosphere on the planet Mars. The air part is not able to protect its surface from cosmic radiation. That is why, in a few days spent on the planet without protection, an astronaut will receive an annual dose of radiation.
Terraforming
Despite all this, people still dream of conquering Mars and even making it habitable. The atmosphere of Mars is one of the main obstacles on this path. However, it is proposed to terraform Mars not only by providing it with oxygen and a dense atmosphere, but also by creating a large source of space fuel. It is proposed to chemically decompose carbon dioxide into oxygen and CO, which can be used to supply the colony and fuel transport in order to establish communication with the Earth.
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 this 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 comparable land mass 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 collapsed 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.
Getting to know any planet begins with its atmosphere. It envelops the cosmic body and protects it from external influences. If the atmosphere is very rarefied, then such protection is extremely weak, but if it is dense, then the planet is in it like in a cocoon - the Earth can serve as an example. However, such an example is isolated in the solar system and does not apply to other terrestrial planets.
Therefore, the atmosphere of Mars (the red planet) is extremely rarefied. Its approximate thickness does not exceed 110 km, and its density in comparison with the earth’s atmosphere is only 1%. In addition to this, the red planet has an extremely weak and unstable magnetic field. As a result, the solar wind invades Mars and disperses atmospheric gases. As a result, the planet loses from 200 to 300 tons of gases per day. It all depends on solar activity and the distance to the star.
From here it is not difficult to understand why the atmospheric pressure is very low. At sea level it is 160 times less than on Earth. On volcanic peaks it is 1 mm Hg. Art. And in deep depressions its value reaches 6 mm Hg. Art. The average value on the surface is 4.6 mm Hg. Art. The same pressure is recorded in the earth's atmosphere at an altitude of 30 km from the earth's surface. With such values, water cannot be present in a liquid state on the red planet.
The atmosphere of Mars contains 95% carbon dioxide.. That is, we can say that he occupies a dominant position. In second place is nitrogen. It accounts for almost 2.7%. The third place is occupied by argon - 1.6%. And oxygen is in fourth place - 0.16%. Carbon monoxide, water vapor, neon, krypton, xenon, and ozone are also present in small quantities.
The composition of the atmosphere is such that it is impossible for people to breathe on Mars. You can only move around the planet in a spacesuit. At the same time, it should be noted that all gases are chemically inert and none of them are poisonous. If the surface pressure was at least 260 mm Hg. Art., then it would be possible to move along it without a spacesuit in ordinary clothes, having only a breathing apparatus.
Some experts believe that several billion years ago the atmosphere of Mars was much denser and richer in oxygen. On the surface there were rivers and lakes of water. This is indicated by numerous natural formations that resemble dry river beds. Their age is estimated at about 4 billion years.
Due to the high rarefaction of the atmosphere, the temperature on the red planet is characterized by high instability. There are sharp daily fluctuations, as well as high temperature differences depending on latitudes. The average temperature is -53 degrees Celsius. In summer at the equator the average temperature is 0 degrees Celsius. At the same time, it can fluctuate during the day from +30 to –60 at night. But temperature records are being observed at the poles. There the temperature can drop to -150 degrees Celsius.
Despite the low density, winds, tornadoes, and storms are often observed in the atmosphere of Mars. Wind speed reaches 400 km/h. It raises pink Martian dust, and it covers the surface of the planet from the prying eyes of people.
It must be said that although the Martian atmosphere is weak, it has enough strength to resist meteorites. Uninvited guests from space, falling to the surface, partially burn up, and therefore there are not so many craters on Mars. Small meteorites burn up completely in the atmosphere and do not cause any harm to Earth’s neighbor.
Vladislav Ivanov