Information about Mars. Terrestrial planets

The red planet - Mars - is named after the ancient Roman god of war of the same name, similar to Ares among the Greeks. It is the fourth planet in the solar system in terms of distance from the Sun. It is believed that the blood-red color of the planet, which is given to it by iron oxide, influenced its name.

Mars has always been curious not only to scientists, but ordinary people various professions. All because humanity had high hopes for this planet, because most people hoped that life also existed on the surface of Mars. Most science fiction novels are written specifically about the planet Mars. Trying to penetrate the secrets and unravel its mysteries, people rapidly studied the surface and structure of the planet. But to get an answer to this, everyone exciting question: “Is there life on Mars?”, but they haven’t succeeded yet. Mars rotates in its slightly elongated orbit around the Sun in 687 Earth days, at a speed of 24 km/s. Its radius is 1.525 astronomical units. The distance from Earth to Mars is constantly changing from a minimum of 55 million km to a maximum of 400 million km. Great oppositions are those periods of time that repeat once every 16–17 years, when the distance between these two planets becomes less than 60 million km. A day on Mars is only 41 minutes longer than on Earth and is 24 hours 62 minutes. The change of day and night, as well as the seasons, also practically repeats those on earth. There are also climatic zones, but due to the greater distance from the Sun, they are much more severe than on our planet. So, average temperature is about –50 °C. The radius of Mars is 3397 km, which is almost half the radius of the Earth - 6378.

Surface and structure of Mars

Mars, along with other terrestrial planets, consists of a crust up to 50 km thick, a mantle up to 1800 km thick and a core with a diameter of 2960 km.

In the center of Mars, the density reaches 8.5 g/m3. In the course of long-term research, it was found that the internal structure of Mars and its current surface consists mainly of basalt. It is assumed that several million, maybe billions of years ago, the planet Mars had an atmosphere. Accordingly, the water was in a liquid state. This is evidenced by numerous riverbeds - meanders, which can still be observed. The characteristic geological formations at their bottom indicate that they flowed very a long period time. Now, for this there is no necessary conditions and water is found only in the layers of soil, under the very surface of Mars. This phenomenon is called permafrost (permafrost). Descriptions of Mars and its characteristics are often found in reports famous explorers"Red Planet".

The rest of the surface of Mars and its relief have no less unique finds. The structure of Mars is characterized by deep craters. At the same time, on this planet, there is the most high mountain in the entire solar system - Olympus - an extinct Martian volcano with a height of 27.5 km and a diameter of 6000 m. There is also a grandiose system of Marineris canyons with a length of about 4 thousand km and a whole region of ancient volcanoes - Elysium.

Phobos and Deimos are natural, but very small, satellites of Mars. They have an irregular shape, and according to one version, they are asteroids captured by the gravity of Mars. The satellites of Mars Phobos (fear) and Deimos (horror) are heroes ancient greek myths, in which they helped the god of war, Ares (Mars), win battles. In 1877, they were discovered by American astronomer Asaph Hall. Both satellites rotate along their axis with the same period, as around Mars, due to this they always face the same side towards the planet. Deimos is gradually being pulled away from Mars, and Phobos, on the contrary, is being attracted even more. But this happens very slowly, therefore, it is unlikely that our next generations will be able to see the fall or complete disintegration of the satellite, or its fall onto the planet.

Characteristics of Mars

Weight: 6.4*1023 kg (0.107 Earth mass)
Diameter at equator: 6794 km (0.53 Earth diameter)
Axis tilt: 25°
Density: 3.93 g/cm3
Surface temperature: –50 °C
Period of rotation around the axis (days): 24 hours 39 minutes 35 seconds
Distance from the Sun (average): 1.53 a. e. = 228 million km
Orbital period around the Sun (year): 687 days
Orbital speed: 24.1 km/s
Orbital eccentricity: e = 0.09
Orbital inclination to the ecliptic: i = 1.85°
Gravity acceleration: 3.7 m/s2
Moons: Phobos and Deimos
Atmosphere: 95% carbon dioxide, 2.7% nitrogen, 1.6% argon, 0.2% oxygen

Mars is a planet in the solar system, one of the first discovered by humanity. To date, of all eight planets, it is Mars that has been studied in the most detail. But this does not stop researchers, but, on the contrary, arouses increasing interest in the “Red Planet” and its study.

Why is it called that?

The planet got its name from Mars, one of the most revered gods of the ancient Roman pantheon, which, in turn, is a reference to the Greek god Ares, the patron of cruel and treacherous war. This name was not chosen by chance - the reddish surface of Mars resembles the color of blood and involuntarily makes us remember the ruler of bloody battles.

The names of the planet's two satellites also bear deep meaning. The words “Phobos” and “Deimos” translated from Greek mean “Fear” and “Horror”; these were the names of the two sons of Ares, who, according to legend, always accompanied their father in battle.

Brief history of the study

For the first time, humanity began to observe Mars not through telescopes. Even the ancient Egyptians noticed the Red Planet as a wandering object, which is confirmed by the ancients written sources. The Egyptians were the first to calculate the trajectory of Mars relative to the earth.

Then astronomers took over the baton Babylonian kingdom. Scientists from Babylon were able to more accurately determine the location of the planet and measure the time of its movement. Next were the Greeks. They managed to create an accurate geocentric model and, with its help, understand the movement of the planets. Then scientists in Persia and India were able to estimate the size of the Red Planet and its distance to Earth.

European astronomers made a huge breakthrough. Johannes Kepler, using Nikolai Kaepernick's model as a basis, was able to calculate the elliptical orbit of Mars, and Christiaan Huygens created the first map of its surface and noticed an ice cap at the planet's north pole.

The advent of telescopes marked a heyday in the study of Mars. Slipher, Barnard, Vaucouleurs and many other astronomers became the greatest explorers of Mars before man entered space.

Human space exploration has made it possible to study the Red Planet more accurately and in detail. In the mid-20th century, with the help of interplanetary stations, precise images of the surface were taken, and ultra-powerful infrared and ultraviolet telescopes made it possible to measure the composition of the planet’s atmosphere and the speed of winds on it.

Subsequently, more and more accurate studies of Mars followed from the USSR, the USA, and then other countries.

The study of Mars continues to this day, and the data obtained only fuels interest in its study.

Characteristics of Mars

Mars is the fourth planet from the Sun, adjacent to the Earth on one side, and Jupiter on the other. In size it is one of the smallest and surpasses only Mercury.
The length of Mars' equator is slightly more than half the length of Earth's equator, and its surface area is approximately equal to the land area of Earth.
There is a change of seasons on the planet, but their duration varies greatly. For example, summer in the northern part is long and cold, and in the southern part it is short and warmer.
The length of a day is quite comparable to that on earth - 24 hours and 39 minutes, that is, a little more.

Surface of the planet

No wonder the second name of Mars is “Red Planet”. Indeed, from a distance its surface looks reddish. This shade of the planet's surface is given by the red dust contained in the atmosphere.

However, up close, the planet sharply changes its color and no longer looks red, but yellow-brown. Sometimes other shades can be mixed with these colors: golden, reddish, greenish. The source of these shades are colored minerals that are also present on Mars.

The main part of the planet’s surface is made up of “continents” - clearly visible light areas, and a very small part - “seas”, dark and poorly visible areas. Most of the “seas” are located in the southern hemisphere of Mars. The nature of the “seas” is still subject to controversy among researchers. But now scientists are most inclined to the following explanation: dark areas are simply irregularities on the surface of the planet, namely craters, mountains and hills.

The following fact is extremely interesting: the surface of the two hemispheres of Mars is very different.

The Northern Hemisphere consists largely of smooth plains, its surface is below average.

The southern hemisphere is mostly cratered, with a surface above average.

Structure and geological data

The study of the magnetic field of Mars and the volcanoes that are located on its surface led scientists to an interesting conclusion: once on Mars, as on Earth, there was a movement of lithospheric plates, which, however, is not observed now.

Modern researchers tend to think that the internal structure of Mars consists of the following components:

Crust (approximate thickness - 50 kilometers)
Silicate mantle
Core (approximate radius - 1500 kilometers)
The planet's core is partially liquid and contains twice as much light elements as the Earth's core.

All about the atmosphere

The atmosphere of Mars is very thin and consists mainly of carbon dioxide. In addition, it contains: nitrogen, water vapor, oxygen, argon, carbon monoxide, xenon and many other elements.

The thickness of the atmosphere is approximately 110 kilometers. Atmospheric pressure at the surface of the planet is more than 150 times less than Earth's (6.1 millibars).

Temperatures on the planet fluctuate over a very wide range: from -153 to +20 degrees Celsius. The lowest temperatures occur at the poles in winter time, the highest are at the equator at midday. Average temperatures are around -50 degrees Celsius.

Interestingly, a thorough analysis of the Martian meteorite “ALH 84001” led scientists to believe that a very long time ago (billions of years ago) the atmosphere of Mars was denser and wetter, and the climate was warmer.

Is there life on Mars?

There is still no clear answer to this question. There is now scientific evidence that supports both theories.

The presence of sufficient nutrients in the planet's soil.
There is a large amount of methane on Mars, the source of which is unknown.
Presence of water vapor in the soil layer.

Instant evaporation of water from the surface of the planet.
Vulnerable to Solar Wind bombardment.
The water on Mars is too salty and alkaline and unsuitable for life.
Intense ultraviolet radiation.

Thus, scientists cannot give an accurate answer, since the amount of necessary data is too small.

The mass of Mars is 10 times less than the mass of Earth.
The first person to see Mars through a telescope was Galileo Galilei.
Mars was originally the Roman god of the harvest, not war.
The Babylonians called the planet "Nergal" (in honor of their deity of evil).
In ancient India, Mars was called "Mangala" (the Indian god of war).
In culture, Mars has become the most popular planet in the solar system.
The daily dose of radiation on Mars is equal to the annual dose on Earth.

RED PLANET MARS

Mars is the first planet in the solar system after Earth, to which for some time now people have begun to show special interest, caused by the hope that developed extraterrestrial life exists there.

The planet is named Mars after the ancient Roman god of war (the same as Ares in ancient greek mythology) behindits blood-red color, due to the presence of iron oxide in the soil of Mars.

Main characteristics

Mars is the fourth most distant planet from the Sun and the seventh largest planet in the solar system.It can be seen from Earth with the naked eye. It is second in brightness only to Venus, the Moon and the Sun.

Mars almost doubled smaller than Earth in size - its equatorial radius is equal to3,396.9 kilometers (53.2% of Earth's). The surface area of Mars is approximately equal to the land area on Earth.

The average distance from Mars to the Sun is 228 million kilometers, the period of revolution around the Sun is 687 Earth days.

The minimum distance from Mars to Earth is 55.75 million kilometers, the maximum is about 401 million kilometers.

Mars is closest to Earth during opposition, when the planet is in the opposite direction to the Sun.The distances between Earth and Mars at moments of opposition vary from 55 to 102 million kilometers. A great opposition is called when the distance between the two planets becomes less than 60 million kilometers. Great oppositions between Earth and Mars occur every 15-17 years (the last one was in August 2003).And the usual ones - every 26 months at different points in the orbit of Mars and Earth.

Mars has a rotation period and seasons similar to those on Earth, but its climate is much colder and drier than Earth's.

The planet's rotation period is 24 hours 37 minutes 22.7 seconds.

On Mars, like on Earth, there are two poles, North and South. Mars rotates quite quickly, so it has a slightly flattened shape at both poles. At the same time, the polar radius of the planet is approximately 21 kilometers less than the equatorial one.

The Martian year consists of 668.6 Martian solar days, called sols.

The mass of the planet Mars is 6.418 × 1023 kilograms (11% of the mass of the Earth).

Mars has two natural satellites - Phobos and Deimos, and three artificial satellites.

By February 2009, there were three operational spacecraft in Mars orbit: Mars Odyssey, Mars Express and Mars Reconnaissance Orbiter, more than any other planet except Earth.

There are several inactive landers and rovers on the surface of Mars that have completed their missions.

Climate of Mars

The climate on Mars, like on Earth, is seasonal. The change of seasons on Mars occurs in much the same way as on Earth, but the climate there is colder and drier than ours. During the cold season, even outside the polar caps, light frost can form on the surface. An image of frost was once taken by the Viking 2 aircraft..

The Phoenix rover at some point managed torecord falling snow on Mars during"Martian winter" Snowfall on Mars was recorded using a laser equipped with the rover. The rover managed to record the snow using a special laser with which it was equipped. Snow fell from a height of about 4000 meters, but it did not reach the surface of the planet, dissolving in the air.

The change of seasons on Mars is ensured bytilt of its axis of rotation. At the same time, the elongation of the orbit leads to large differences in the length of the seasons. Unlike earthly ones, which have the same duration of 3 months. There are northern springs and summers on Mars, which occur in a portion of the orbit away from the Sun. These seasons together last 371 sol, that is, significantly more than half of the Martian year. Therefore, on Mars, the northern summer is long and cool, and the southern summer is short and hot.

Mars is characterized by sharp temperature changes. Temperatures at the planet's equator range from +30°C at noon to −80°C at midnight. Near the poles, the temperature sometimes drops to −143°C, at which temperature carbon dioxide condenses. Mars is a very cold world, but the climate there is not much harsher than in Antarctica.

There is currently no liquid water on Mars. However, most likely, the white polar caps, discovered in 1704, consist of water ice mixed with solid carbon dioxide. In winter, they extend a third (the southern polar cap - half) the distance to the equator. In the spring, this ice partially melts, and a wave of darkening, which was previously mistaken for Martian plants, spreads from the poles to the equator.

The appearance of Mars varies greatly depending on the time of year. First of all, the changes in the polar ice caps are striking. They wax and wane, creating seasonal patterns in the atmosphere and surface of Mars.The polar caps consist of two components: seasonal - carbon dioxide and secular - water ice. The thickness of the caps can range from 1 meter to 3.7 kilometers.

Previously, many researchers seriously believed that there is still liquid water on the surface of Mars. This opinion was based on observations of periodic changes in light and dark areas, especially in the polar latitudes, which were similar to continents and seas.

Dark grooves on the surface of Mars have been explained by some observers as channels for liquid water.

It was later proven that these grooves did not actually exist, but were just an optical illusion.

Research conducted by the Mariner 4 spacecraft in 1965 showed that there is currently no liquid water on Mars.

Due to low pressure, water cannot exist in a liquid state on the surface of Mars. With such a small pressure that is currently operating on the planet, it boils at very low temperatures, but it is likely that conditions were different in the past, and therefore the presence of primitive life on the planet cannot be ruled out.

On July 31, 2008, ice water was discovered on Mars at the landing site of NASA's Phoenix spacecraft. The device discovered ice deposits directly in the ground.

Data from NASA's Mars rovers Spirit and Opportunity also indicate the presence of water in the past (minerals were found that could only have formed as a result of prolonged exposure to water).

A glacier hundreds of meters thick covers an area of thousands of square kilometers, and its further study can provide information about the history of the Martian climate.

By modern ideas, the total volume of ice enclosed in the polar cap of the northern hemisphere is approximately 1.5 million kilometers, therefore, in its melted form, this ice could not have formed a giant ocean, which, according to many researchers, once covered almost the entire northern hemisphere of Mars. So it remains a mystery where the water that once abounded on the now arid planet went.

Presumablyin the past, the climate of Mars could have been warmer and wetter, and there was liquid water, and it even rained.

Magnetic field and atmosphere of Mars

Mars has a magnetic field, but it is weak and extremely unstable. In different parts of the planet it can differ from 1.5 to 2 times. At the same time, the magnetic poles of the planet do not coincide with the physical ones. This suggests that the iron core of Mars is more or less motionless relative to its crust, that is, the mechanism responsible for the Earth’s magnetic field does not work on Mars.

Current models of the internal structure of Mars suggest that Mars consists of a crust with an average thickness of 50 kilometers (and a maximum thickness of up to 130 kilometers), a silicate mantle (iron-enriched mantle) with a thickness of 1,800 kilometers, and a core with a radius of 1,480 kilometers.

According to calculations, the core of Mars has a mass of up to 9% of the mass of the planet. It consists of iron and its alloys, while the core is in a liquid state.

Perhaps in the distant past as a result of a collision with a large celestial body the rotation of the core stopped, as well as the loss of the main volume of the atmosphere.The loss of the magnetic field is thought to have occurred about 4 billion years ago.

Because Mars' magnetic field is so weak, the solar wind easily penetrates its atmosphere. Because of this, many reactions under the influence of solar radiation on Mars occur almost at its very surface.On Earth, a strong magnetic field does not transmit solar radiation, therefore all these reactions occur in the ionosphere and above.

The Martian ionosphere extends over the planet's surface from 110 to 130 kilometers.

The atmosphere of Mars consists of 95% carbon dioxide. The atmosphere also contains 2.5-2.7% nitrogen, 1.5-2% argon, 0.13% oxygen, 0.1% water vapor, 0.07% carbon monoxide.

In addition, the atmosphere of Mars is very thin. The pressure at the surface of Mars is 160 times less than that of Earth at the average surface level. Due to the large difference in altitude on Mars, the pressure at the surface varies greatly.

Unlike Earth's, the mass of the Martian atmosphere varies greatly throughout the year due to the melting and freezing of the polar caps containing carbon dioxide.

There is evidence that the atmosphere may have been denser in the past.

Topography of Mars

Research has shown that two-thirds of the surface of Mars is occupied by light areas called continents, and the remaining third by dark areas called seas. The nature of the dark areas is still a matter of debate.But in fact, no water was found in the Martian seas.

The seas are concentrated mainly in the southern hemisphere of the planet. There are only two in the northern hemisphere large seas- Acidalia and Bolshoi Syrt.

Large-scale images show that the dark areas actually consist of groups of dark streaks and spots associated with craters, hills and other obstacles in the path of winds. Seasonal and long-term changes in their size and shape are apparently associated with a change in the ratio of surface areas covered with light and dark matter.

The hemispheres of Mars differ quite greatly in the nature of their surface. The surface of Mars has a reddish color due to large impurities of iron oxides.

Everywhere on the surface of Mars lie blocks of stone - pieces of volcanic rock that broke off during marsquakes or meteorite falls.

From time to time you come across craters - the remains of meteorite impacts.

In some places, the surface is covered with multi-layered rocks similar to terrestrial sedimentary rocks left behind after the sea retreated.

In the southern hemisphere, the surface is 1-2 kilometers above average and is densely dotted with craters. This part of Mars resembles the lunar continents.

A large number of craters in the southern hemisphere may indicate that the surface here is ancient - 3-4 billion years old.

Rovers exploring the planet left their footprints on the untouched surface.

In the north, the surface is mostly below average, there are few craters, and the bulk is relatively smooth plains, probably formed by lava flooding and soil erosion.

In the northern hemisphere there are two areas of large volcanoes - Tharsis and Elysium.

Tharsis is a vast volcanic plain 2000 kilometers long, reaching an altitude of 10 kilometers above average. There are three large volcanoes on it.

On the edge of Tharsis is the highest on Mars and on the planets in solar system mountain - Martian extinct volcano Olympus.

Olympus reaches 27 kilometers in height and 550 kilometers in diameter. The cliffs that surround the volcano reach 7 kilometers in height in some places.

Currently, all Martian volcanoes are inactive. Traces of volcanic ash found on the slopes of other mountains suggest that Mars was once volcanically active.

A typical landscape on Mars is the Martian desert.

Sand dunes, giant canyons and faults, as well as meteorite craters have been photographed on Mars. The most ambitious canyon system, the Valles Marineris, stretches for almost 4,500 kilometers (a quarter of the planet's circumference), reaching a width of 600 kilometers in width and 7-10 kilometers in depth.

Soil of Mars

The composition of the surface layer of Martian soil, according to data from landers, is different in different places.

The soil mainly consists of silica (20-25%), containing an admixture of iron oxide hydrates (up to 15%), giving the soil a reddish color. The soil contains significant impurities of sulfur, calcium, aluminum, magnesium, and sodium compounds. The ratio of acidity and some other parameters of Martian soils are close to those on Earth and theoretically it would be possible to grow plants on them.

From lead chemist Sam Coonaves:

“In fact, we have found that the soil on Mars meets the requirements and also contains the necessary elements for the emergence and maintenance of life, both in the past, present and future... Such soil is quite suitable for growing various plants, such as asparagus. There is nothing here that makes life impossible. On the contrary, with each new study we find additional evidence in favor of the possibility of its existence.”

Interesting phenomena on Mars

The Mars Odyssey probe discovered active geysers on the southern polar cap of Mars. With spring warming, jets of carbon dioxide rush upward to great heights, taking with them dust and sand. The spring melting of the polar caps leads to a sharp increase in atmospheric pressure and the movement of large masses of gas to the opposite hemisphere.

The speed of the winds blowing in this case is 10-40 m/s, sometimes up to 100 m/s. The wind lifts large amounts of dust from the surface, leading to dust storms. Severe dust storms almost completely obscure the surface of the planet. Dust storms have a noticeable effect on the temperature distribution in the Martian atmosphere.

After the landing of automatic vehicles on the surface of Mars, it became possible to conduct astronomical observations directly from the surface of the planet.

The picture of the night sky of Mars (and astronomical phenomena observed from the planet) differs from that on Earth and in many ways seems unusual and interesting.

For example, at noon the sky of Mars is yellow-orange. The reason for such differences from color range Earth's sky - the properties of the thin, rarefied atmosphere of Mars containing suspended dust.

Presumably, the yellow-orange color of the sky is caused by the presence of 1% magnetite in dust particles constantly suspended in the Martian atmosphere and raised by seasonal dust storms. The duration of storms can reach 50-100 days.

The evening dawn on Mars turns the sky fiery red or deep orange.

Mars is the fourth planet in our solar system and the second smallest after Mercury. Named after the ancient Roman god of war. Its nickname "Red Planet" comes from the reddish hue of the surface, which is due to the predominance of iron oxide. Every few years, when Mars is in opposition to Earth, it is most visible in the night sky. For this reason, people have observed the planet for many millennia, and its appearance in the sky played a role big role in the mythology and astrological systems of many cultures. IN modern era she became a real treasure scientific discoveries, which expanded our understanding of the solar system and its history.

Size, orbit and mass of Mars

The radius of the fourth planet from the Sun is about 3396 km at the equator and 3376 km in the polar regions, which corresponds to 53% And although it is about half as large, the mass of Mars is 6.4185 x 10²³ kg, or 15.1% of the mass of our planet. The axis tilt is similar to that of Earth and is equal to 25.19° to the orbital plane. This means that the fourth planet from the Sun also experiences the change of seasons.

At its greatest distance from the Sun, Mars orbits at a distance of 1.666 AU. e., or 249.2 million km. At perihelion, when it is closest to our star, it is 1.3814 AU away from it. e., or 206.7 million km. The Red Planet takes 686,971 Earth days, equivalent to 1.88 Earth years, to orbit the Sun. In Martian days, which on Earth are equal to one day and 40 minutes, a year lasts 668.5991 days.

Soil composition

With an average density of 3.93 g/cm³, this characteristic of Mars makes it less dense than Earth. Its volume is about 15% of the volume of our planet, and its mass is 11%. Red Mars is a consequence of the presence of iron oxide on the surface, better known as rust. The presence of other minerals in the dust ensures the presence of other shades - gold, brown, green, etc.

This terrestrial planet is rich in minerals containing silicon and oxygen, metals and other substances that are usually found in rocky planets. The soil is slightly alkaline and contains magnesium, sodium, potassium and chlorine. Experiments carried out on soil samples also show that its pH is 7.7.

Although liquid water cannot exist on it due to its thin atmosphere, large concentrations of ice are concentrated within the polar ice caps. In addition, the permafrost belt extends from the pole to 60° latitude. This means that water exists beneath most of the surface as a mixture of its solid and liquid states. Radar data and soil samples confirmed the presence also in mid-latitudes.

Internal structure

The 4.5 billion-year-old planet Mars consists of a dense metallic core surrounded by a silicon mantle. The core is composed of iron sulfide and contains twice more lungs elements than the Earth's core. The average thickness of the crust is about 50 km, the maximum is 125 km. If we take into account that the earth's crust, the average thickness of which is 40 km, is 3 times thinner than the Martian crust.

Current models of its internal structure suggest that the core has a radius size of 1700-1850 km and is composed primarily of iron and nickel with approximately 16-17% sulfur. Due to its smaller size and mass, the gravity on the surface of Mars is only 37.6% that of Earth. here it is 3.711 m/s², compared to 9.8 m/s² on our planet.

Surface characteristics

Red Mars is dusty and dry from above, and geologically it closely resembles Earth. It has plains and mountain ranges, and even the largest sand dunes in the solar system. The highest mountain, the Olympus shield volcano, and the longest and deepest canyon, the Valles Marineris, are also located here.

Impact craters are typical elements of the landscape that dot the planet Mars. Their age is estimated at billions of years. Due to the slow rate of erosion, they are well preserved. The largest of them is the Hellas Valley. The circumference of the crater is about 2300 km, and its depth reaches 9 km.

Gullies and channels can also be discerned on the surface of Mars, and many scientists believe that water once flowed through them. Comparing them with similar formations on Earth, it can be assumed that they were at least partially formed by water erosion. These canals are quite large - 100 km wide and 2 thousand km long.

Moons of Mars

Mars has two small moons, Phobos and Deimos. They were discovered in 1877 by astronomer Asaph Hall and bear the names of mythical characters. Following the tradition of taking their names from classical mythology, Phobos and Deimos are the sons of Ares, the Greek god of war who was the prototype of the Roman Mars. The first of them represents fear, and the second - confusion and horror.

Phobos is about 22 km in diameter, and the distance to Mars from it is 9234.42 km at perigee and 9517.58 km at apogee. This is below synchronous altitude, and the satellite takes only 7 hours to orbit the planet. Scientists estimate that in 10-50 million years, Phobos may fall to the surface of Mars or disintegrate into a ring structure around it.

Deimos has a diameter of about 12 km, and its distance to Mars is 23455.5 km at perigee and 23470.9 km at apogee. The satellite makes a full revolution in 1.26 days. Mars may also have additional satellites, the sizes of which are less than 50-100 m in diameter, and there is a ring of dust between Phobos and Deimos.

According to scientists, these moons were once asteroids, but then they were captured by the planet's gravity. The low albedo and composition of both moons (carbonaceous chondrite), which is similar to asteroid material, support this theory, and Phobos' unstable orbit would seem to suggest a recent capture. However, both moons' orbits are circular and in the plane of the equator, which is unusual for captured bodies.

Atmosphere and climate

The weather on Mars is due to the presence of a very thin atmosphere, which consists of 96% carbon dioxide, 1.93% argon and 1.89% nitrogen, as well as traces of oxygen and water. It is very dusty and contains particulate matter measuring 1.5 microns in diameter, which turns the Martian sky dark yellow when viewed from the surface. Atmospheric pressure varies between 0.4-0.87 kPa. This is equivalent to about 1% of the Earth's at sea level.

Due to the thin layer of gaseous shell and greater distance from the Sun, the surface of Mars warms up much worse than the surface of the Earth. On average it is -46 °C. In winter it drops to -143 °C at the poles, and in summer at noon at the equator it reaches 35 °C.

Dust storms are raging on the planet, which turn into small tornadoes. More powerful hurricanes occur when dust rises and is heated by the Sun. The winds intensify, creating storms whose scales are measured in thousands of kilometers and their duration is several months. They effectively hide almost the entire surface area of Mars from view.

Traces of methane and ammonia

Traces of methane were also found in the planet's atmosphere, the concentration of which is 30 parts per billion. It is estimated that Mars should produce 270 tons of methane per year. Once released into the atmosphere, this gas can only exist for a limited period of time (0.6-4 years). Its presence, despite its short lifetime, indicates that an active source must exist.

Possible possibilities include volcanic activity, comets, and the presence of methanogenic microbial life forms beneath the planet's surface. Methane can be produced through non-biological processes called serpentinization, involving water, carbon dioxide and olivine, which is common on Mars.

Express also detected ammonia, but with relatively short time life. It is not clear what produces it, but volcanic activity has been suggested as a possible source.

Planet exploration

Attempts to find out what Mars is began in the 1960s. Between 1960 and 1969 Soviet Union launched 9 unmanned spacecraft to the Red Planet, but all of them failed to reach the target. In 1964, NASA began launching Mariner probes. The first were Mariner 3 and Mariner 4. The first mission failed during deployment, but the second, launched 3 weeks later, successfully completed the 7.5-month journey.

Mariner 4 took the first close-up images of Mars (showing impact craters) and provided precise data on atmospheric pressure at the surface and noted the absence of a magnetic field and radiation belt. NASA continued the program with another pair of flyby probes, Mariner 6 and 7, which reached the planet in 1969.

In the 1970s, the USSR and the United States competed to see who would be the first to launch an artificial satellite into Mars orbit. The Soviet M-71 program included three spacecraft - Kosmos-419 (Mars-1971C), Mars-2 and Mars-3. The first heavy probe crashed during launch. The subsequent missions, Mars 2 and Mars 3, were a combination of an orbiter and a lander and became the first extraterrestrial landings (other than the Moon).

They were successfully launched in mid-May 1971 and flew from Earth to Mars for seven months. On November 27, the Mars-2 lander made an emergency landing due to an onboard computer failure and became the first man-made object to reach the surface of the Red Planet. On December 2, Mars 3 made a routine landing, but its transmission was interrupted after 14.5 seconds of broadcast.

Meanwhile, NASA continued the Mariner program, and Probes 8 and 9 were launched in 1971. Mariner 8 crashed into the Atlantic Ocean during launch. But the second spacecraft not only reached Mars, but also became the first to be successfully launched into its orbit. While the planet-scale dust storm lasted, the satellite managed to take several photographs of Phobos. As the storm subsided, the probe captured images that provided more detailed evidence that water once flowed on the surface of Mars. It has been determined that a hill called the Snows of Olympus (one of the few objects that remained visible during the planetary dust storm) is also the most highly educated in the solar system, which led to its renaming to Mount Olympus.

In 1973, the Soviet Union sent four more probes: the 4th and 5th Mars orbiters, and the orbiters and landers Mars 6 and 7. All interplanetary stations except Mars 7 transmitted data , and the Mars-5 expedition turned out to be the most successful. Before the transmitter housing depressurized, the station managed to transmit 60 images.

By 1975, NASA had launched Viking 1 and 2, consisting of two orbiters and two landers. The mission to Mars was aimed at searching for traces of life and observing its meteorological, seismic and magnetic characteristics. Results from biological experiments aboard the Viking landers were inconclusive, but a reanalysis of the data published in 2012 suggested evidence of microbial life on the planet.

Orbiters have provided additional evidence that water once existed on Mars - large floods created deep canyons thousands of kilometers long. Additionally, areas of braided streams in the southern hemisphere suggest that precipitation once occurred there.

Resumption of flights

The fourth planet from the sun was not explored until the 1990s, when NASA sent the Mars Pathfinder mission, which consisted of a spacecraft that landed a station with the traveling Sojourner probe. The device landed on Mars on July 4, 1987 and became proof of the viability of technologies that would be used in future expeditions, such as air-cushion landing and automatic obstacle avoidance.

The next mission to Mars was the MGS mapping satellite, which reached the planet on September 12, 1997, and began operations in March 1999. Over the course of one full Martian year, from a low altitude in almost polar orbit, it studied the entire surface and atmosphere and sent back more data about the planet than all previous missions combined.

On November 5, 2006, MGS lost contact with Earth, and NASA's efforts to restore it were terminated on January 28, 2007.

In 2001, the Mars Odyssey Orbiter was sent to find out what Mars is. Its goal was to search for evidence of water and volcanic activity on the planet using spectrometers and thermal imagers. In 2002, it was announced that the probe had detected large quantities of hydrogen - evidence of the existence of huge deposits of ice in the top three meters of soil within 60° of the south pole.

On June 2, 2003, Mars Express was launched, a spacecraft consisting of a satellite and the Beagle 2 lander. It entered orbit on December 25, 2003, and the probe entered the planet's atmosphere on the same day. Before ESA lost contact with the lander, Mars Express Orbiter confirmed the presence of ice and carbon dioxide at the south pole.

In 2003, NASA began exploring the planet under the MER program. It used two rovers, Spirit and Opportunity. The mission to Mars had the task of examining various rocks and soils in order to find evidence of the presence of water.

The Mars Reconnaissance Orbiter (MRO) was launched on 08/12/05 and reached the planet's orbit on 03/10/06. The spacecraft carries scientific instruments designed to detect water, ice and minerals on and below the surface. In addition, MRO will support future generations of space probes by daily monitoring Mars' weather and surface conditions, searching for future landing sites, and testing a new telecommunications system that will speed up communications with Earth.

On August 6, 2012, the Martian mission landed in Gale Crater. scientific laboratory NASA MSL and Curiosity rover. With their help, many discoveries were made regarding local atmospheric and surface conditions, and organic particles were also discovered.

On November 18, 2013, in another attempt to find out what Mars is, the MAVEN satellite was launched, the purpose of which is to study the atmosphere and relay signals from robotic rovers.

Research continues

The fourth planet from the Sun is the most studied in the solar system after Earth. Currently, the Opportunity and Curiosity stations operate on its surface, and 5 spacecraft operate in orbit - Mars Odyssey, Mars Express, MRO, MOM and Maven.

These probes were able to transmit incredibly detailed images of the Red Planet. They helped discover that there was once water there, and confirmed that Mars and Earth are very similar - they have polar caps, seasons, an atmosphere and the presence of water. They also showed that organic life can exist today and most likely existed in the past.

Humanity's obsession with discovering what Mars is continues unabated, and our efforts to study its surface and unravel its history are far from over. In the coming decades, we will likely continue to send rovers there and will send a man there for the first time. And over time, given the availability of the necessary resources, the fourth planet from the Sun will one day become habitable.

And the seventh largest:

Orbital distance from the Sun: 227,940,000 km (1.52 AU)

Diameter: 6794 km

Mars has been known since prehistoric times. The planet has been carefully studied using ground-based observatories.

First spaceship The one that visited Mars was Mariner 4 (USA) in 1965. Others followed, such as Mars 2 (USSR), the first spacecraft to land on Mars, followed by two Viking spacecraft (USA) with landers in 1976.

This was followed by a 20-year break in spacecraft launches to Mars, and on July 4, 1997, the Mars Pathfinder successfully landed

In 2004, the Opportunity rover landed on Mars, conducted geological research and sent many images back to Earth.

In 2008, the Phoenix spacecraft landed on the northern plains of Mars to search for water.

Three were then sent into orbit around Mars. orbital stations Mars Reconnaissance Orbiter, Mars Odyssey and Mars Express, which are currently in operation.

The MSL Curiosity (CIF) spacecraft successfully landed on Mars on August 6, 2012. The landing was broadcast live on the NASA website. The device landed in a given area - in the Gale crater.
The Mars rover "Curiosity" (from the English "curiosity", "curiosity") was launched on November 26, 2011. It is the largest robotic vehicle in the entire history of Mars exploration - its mass is more than 900 kilograms.
One of the main tasks of Curiosity is to analyze the chemical composition of soil on the surface and at shallow depths. Its analytical instruments include a quadrupole mass spectrometer, gas chromatograph and X-ray spectrometers. In addition, it is equipped with the Russian-made DAN neutron detector, designed to search for ice under the surface of the planet.

The orbit of Mars is elliptical. This significantly affects the temperature with a difference of 30 C , from the side of the Sun, measured at the aphelion of the orbit and perihelion. This has a big impact on the climate of Mars. While the average temperature on Mars is about -55 C, the surface temperature of Mars ranges from -133 C at the winter pole to almost 27 C at the day side during the summer.

Even though Mars is much smaller than Earth, its area is approximately the same as Earth's land surface area.

Mars has one of the most diverse and interesting landscapes terrains among planets:

Mount Olympus : The largest mountain in the solar system, its height is 24 km above the surrounding plain. The foot of the mountain is 500 km in diameter and is framed by cliffs 6 km high.

Tarsis: A huge bulge on the surface of Mars, measuring about 4000 km across and 10 km high.

Valles Marineris: a system of canyons 4000 km long and from 2 to 7 km deep;

Plain of Hellas: a meteorite crater in the southern hemisphere more than 6 km deep and 2000 km in diameter.

Much of the surface of Mars is covered with very old craters, but there are also much younger rift valleys, ridges, hills and plains.

The southern hemisphere is covered with craters, much like the Moon. The Northern Hemisphere consists of plains that are much younger, smaller in height, and have a much more complex history. A sharp change in altitude of several kilometers occurs at the border of the hemispheres. The reasons for this global dichotomy and the presence of sharp boundaries are unknown.

A cross-section of the planet looks something like this: the crust in the southern hemisphere is about 80 km and about 30 km in the northern hemisphere, the core is very dense, about 1700 km in radius.

The relatively low density of Mars compared to other terrestrial planets indicates that its core may contain relatively a large share sulfur and iron (iron and iron sulfide).

Mars, like Mercury and the Moon, has no currently active tectonic strata and no signs of recent horizontal surface movement. On Earth, evidence of this movement are folded mountains.

There are currently no signs of ongoing volcanic activity. However, data from the Mars Global Surveyor spacecraft indicate that Mars very likely had tectonic activity at some point in the past.

There is very clear evidence of erosion in many places on Mars, including large floods and small river systems. In the past, there was some kind of liquid on the surface of the planet.

There may have been seas and even oceans on Mars; the Mars Global Surveyor has provided very clear images of a layered soil system. It is rather caused by the presence of fluid in the past. The age of channel erosion is estimated to be approximately 4 billion years.

Mars Express in early 2005 sent back images of a dry sea that had been filled with liquid as recently as perhaps 5 million years ago.

Early in its history, Mars was much more like Earth. As on Earth, almost all of the carbon dioxide was used to form carbonate rocks.

Mars has a very thin atmosphere, consisting mainly of small amounts of remaining carbon dioxide (95.3%), nitrogen (2.7%), argon (1.6%), traces of oxygen (0.15%), water (0 .03%).

The average surface pressure on Mars is only about 7 millibars (less than 1% of the pressure on Earth), but it varies greatly with altitude. So, 9 millibars in the deepest depressions and 1 millibar at the top of Mount Olympus.

However, the wind on Mars is very strong winds and huge dust storms that sometimes cover the entire planet for months.

Telescopic observations have shown that Mars has permanent caps at both poles, visible even with a small telescope. They consist of water ice and solid carbon dioxide ("dry ice"). Ice caps have a layered structure with alternating layers of ice and varying concentrations of dark dust.

The Viking spacecraft (USA) carried out studies from landers to determine the existence of life on Mars. The results have been somewhat mixed, but most scientists now believe they have no evidence of life on Mars. Optimists point out that only two tiny soil samples have been analyzed, and not from the most favorable locations.

Large, but not global, weak magnetic fields exist in various regions of Mars. This unexpected discovery was made by the Mars Global Surveyor a few days after it entered Mars orbit. These may be remnants of a previously global magnetic field.

If there was a magnetic field on Mars, then the existence of life on it becomes more likely.

Characteristics of Mars:

Weight (10 24 kg): 0.64185

Volume (10 10 km cubic): 16,318

Equatorial radius: 3397 km

Polar radius: 3375 km

Volumetric average radius: 3390 km

Average density: 3933 kg/m 3

Radius: 1700 km

Gravity (ed.) (m/s): 3.71

Gravity acceleration (ed.) (m/s): 3.69

Second escape velocity (km/s): 5.03