Which planet has a diameter of 4880. Planet Mercury: brief description and interesting facts

16.10.2019 -

Mercury is similar in physical characteristics to the Moon. It has no natural satellites, its atmosphere is very rarefied. This planet has a large iron core, accounting for 83% of the volume of the entire planet. This core is the source magnetic field, intensity 0.01 of the earth's. The surface temperature of the planet is - 90 - 700 K (-183.15-426.85 C). The solar side of the planet is heating up significantly more than its back side and polar regions.

Craters of Mercury

On the surface of Mercury there is a large number of craters, this landscape is very reminiscent of the lunar one. On different areas Mercury's crater density is different. It is possible that the areas of the planet's surface that are more heavily dotted with craters are more ancient, and those that are less dotted are younger. They were formed as a result of lava flooding the old surface. At the same time, there are fewer large craters on Mercury than on the Moon. The diameter of the largest crater on Mercury is 716 km, it was named after Rembrandt, the great Dutch painter. Also on Mercury there are formations that are not similar on the Moon. For example, scarps are numerous jagged slopes that extend for hundreds of kilometers. When studying the scarps, it was found that they were formed during the compression of the surface that accompanied the cooling of Mercury, during which the surface area of the planet decreased by 1%. Because There are well-preserved large craters on the surface of Mercury, which means that over the past 3 - 4 billion years there has been no movement of sections of the crust on a large scale, there was no erosion on the surface (by the way, the latter almost completely confirms the impossibility of the existence in the history of Mercury of any some significant atmosphere).

During the research, the Messenger probe obtained photographs of more than 80% of the planet's surface, as a result of which it was determined that it was homogeneous, unlike the surface of Mars or the Moon, in which one hemisphere is very different from the other.
The elemental composition of Mercury's surface, obtained by the Messenger X-ray fluorescence spectrometer, showed that the planet's surface is rich in plagioclase feldspar, characteristic of the continental regions of the Moon, and, in comparison, poor in calcium and aluminum. It is also rich in magnesium and low in iron and titanium, which allows it to fill the gap between ultrabasic rocks, like terrestrial komatiites, and typical basalts. A relative abundance of sulfur has also been discovered - this means that the planet was formed under reducing conditions.
The craters of Mercury differ from each other. They can be small bowl-shaped depressions, or multi-ring impact craters that are hundreds of kilometers in diameter. Mercury's craters to varying degrees destroyed. There are more or less well-preserved ones, with long rays located around them, formed during the release of substance from the impact of the impact. There are also very destroyed remains of craters.
The Plain of Heat (lat. Caloris Planitia) is one of the most noticeable features of the relief of Mercury. It is so named because it is located next to one of the “hot longitudes”. The diameter of this plain is about 1550 km.
Most likely, the body, the collision of which with the surface of Mercury formed a crater, was at least 100 km in diameter. The impact was so strong that seismic waves, having passed through the entire planet and gathered at the opposite point of the surface, caused the formation of a kind of “chaotic” rugged landscape on Mercury. The force of the impact is also evidenced by the fact that it provoked the emission of lava, as a result of which the Zhary Mountains, more than 2 km high, were formed around the crater. Kuiper Crater (60 km across) is the point on the planet's surface with the highest albedo. Most likely, Kuiper crater is one of the “last” large craters on Mercury to form.
Another interesting arrangement of craters on the planet was discovered by scientists in 2012: the sequence of crater locations forms the face of Mickey Mouse. Maybe in the future this configuration will be called that way.

Geology of Mercury

More recently, it was believed that in the depths of Mercury there is a metallic core, the radius of which
1800 - 1900 km, it makes up 60% of the mass of the planet, since a weak magnetic field was discovered by the Mariner 10 spacecraft. In addition, according to scientists, it was believed that the core of Mercury, due to the small size of the planet, should not be liquid. After five years of radar observations, Jean-Luc Margot's group took stock in 2007, and as a result, various variations in Mercury's rotation were noted, which are too large for a planet with a solid core. Based on this, we can say with almost one hundred percent accuracy that Mercury’s core is liquid.

Compared to any planet solar system Mercury's core has a higher percentage of iron. There are several versions of the explanation for this. The most widely accepted theory in the world of science says that Mercury, while originally 2.25 times as massive as it is today, had the same proportion of silicates and metal as a normal meteorite. But at the very beginning of the history of the Solar System, a planet-like body, several hundred kilometers in diameter and 6 times less mass, collided with Mercury. Because of this collision, a large part of the primary crust and mantle was torn away from the planet, as a result of which the relative proportion of the core in the composition of Mercury increased. By the way, to explain the formation of the Moon, a similar hypothesis was proposed, called the Giant Impact Theory. But this theory is contradicted by the first data obtained in the process of studying the elemental composition of the surface of Mercury using the AMS Messenger gamma spectrometer (it allows you to measure the content of radioactive isotopes). It turned out that there is a lot of potassium on the planet (a volatile element when compared with thorium and uranium, which are more refractory). This is not consistent with the inevitable collision high temperatures. Based on this, it becomes clear that the elemental composition of Mercury coincides with the primary elemental composition of the material that formed it, which is close to anhydrous cometary particles and enstatite chondrites, while the iron content in the latter is currently low to explain the high average density of the planet.
A silicate mantle (500-600 km thick) surrounds Mercury's core. The thickness of its crust ranges from 100 to 300 km (according to Mariner-10 data).

Geological history of Mercury

The geological history of the planet is divided into eras, like those of Mars, the Moon and the Earth. These eras are called as follows (to the later from the earlier): 1- pre-Tolstovsky, 2- Tolstoyan, 3- Kalorian, 4- late Kalorian, 5- Mansurian and 6- Kuiper. And the relative geological age of Mercury is divided into periods according to these eras. True, the absolute age measured in years has not been precisely established.
About 4.6 billion years ago, when the planet was already formed, there was an intense collision with comets and asteroids. The last massive bombardment of Mercury was 3.8 billion years ago. Some areas (for example, the Plain of Heat) were created, among other things, by filling them with lava. As a result, smooth cavities similar to those of the Moon formed inside the craters.
After this, as Mercury cooled and contracted, faults and ridges formed. The later time of their formation is evidenced by their location on the surface of large relief objects, such as plains and craters. The planet's time of volcanism ended after the mantle shrank enough to prevent lava from reaching Mercury's surface. It is possible that this happened during the first 700-800 million years since the formation of Mercury. Later changes in the planet's landscape were caused by impacts of cosmic bodies on its surface.

Mercury's magnetic field

The strength of Mercury's magnetic field is approximately one hundred times less than that of Earth and is equal to ~300 nT. Mercury's magnetic field has a dipole structure, is very symmetrical, its axis is only 10 degrees deviated from Mercury's rotation axis. This significantly reduces the number of hypotheses explaining the origin of Mercury's magnetic field. Presumably, Mercury's magnetic field arises as a result of the dynamo effect (the same happens on Earth). Perhaps this effect is a consequence of the circulation of the liquid core. The very strong tidal effect occurs due to the very pronounced eccentricity of Mercury. This tidal effect keeps the core liquid, which is mandatory conditions to create a dynamo effect. The planet's magnetic field is so strong that it can change the direction of the solar wind around Mercury, resulting in the creation of its magnetosphere. And although it is so small that it would fit inside the Earth, it is powerful enough to catch the plasma of the solar wind. As a result of observations obtained with the help of Mariner 10, it turned out that there is low-energy plasma in the magnetosphere of the night side of Mercury. Explosions of active particles in the tail of the magnetosphere indicate its inherent dynamic qualities.

On October 6, 2008, Messenger, flying by Mercury for the second time, recorded a large number of windows in the planet’s magnetic field. Messenger discovered the phenomenon of magnetic vortices. These are intertwined magnetic field knots that connect the spacecraft to Mercury's magnetic field. The diameter of the vortex was 800 km, this is a third of the radius of the planet. The solar wind creates such a vortex form of the magnetic field. As the solar wind flows around Mercury's magnetic field, it binds and rushes with it, forming into vortex-like structures. Such vortices create windows in the planet’s magnetic shield; the solar wind penetrates through them, reaching the surface of the planet. The connection between interplanetary and planetary magnetic fields (magnetic reconnection) is a common cosmic phenomenon that also occurs near the Earth at a time when it creates magnetic vortices. But the frequency of Mercury’s magnetic reconnection, according to Messenger, is 10 times higher.

To get an idea of how big Mercury is, let's look at it in comparison to our planet.
Its diameter is 4879 km. This is approximately 38% of the diameter of our planet. In other words, we could put three Mercurys side by side and they would be slightly larger than Earth.

What is the surface area

The surface area is 75 million square kilometers, which is approximately 10% of the Earth's surface area.

If you could unfold Mercury, it would become almost twice the size of Asia (44 million square kilometers).

What about volume? The volume is 6.1 x 10*10 km3. This is a large number, but it is only 5.4% of the Earth's volume. In other words, we could put 18 Mercury-sized objects inside the Earth.

Weight is 3.3 x 10*23 kg. Again, this is a lot, but in terms of ratio it is only equal to 5.5% of the mass of our planet.

Finally, let's look at the force of gravity on its surface. If you could stand on the surface of Mercury (in a good, heat-resistant spacesuit), you would feel 38% of the gravity you feel on Earth. In other words, if you weigh 100 kg, then on Mercury there are only 38 kg.


	· · · ·
	·

Mercury is the smallest planet in the world, is located at the closest distance from the Sun, and belongs to the terrestrial planets. The mass of Mercury is approximately 20 times less than that of Earth; the planet has no natural satellites. According to scientists, the planet has a frozen iron core, occupying about half of the planet’s volume, followed by a mantle, and a silicate shell on the surface.

The surface of Mercury is very reminiscent of the Moon, and is densely covered with craters, most of which are of impact origin - from collisions with fragments that remained from the formation of the Solar system about 4 billion years ago. The planet's surface is covered with long, deep cracks, which may have formed as a result of the gradual cooling and compression of the planet's core.

The similarity between Mercury and the Moon lies not only in the landscape, but also in a number of other features, in particular the diameter of both celestial bodies - 3476 km for the Moon, 4878 for Mercury. A day on Mercury is equal to approximately 58 Earth days, or exactly 2/3 of a Mercury year. Connected with this is another curious fact of “lunar” similarity - from the Earth, Mercury, like the Moon, is always visible only the “front side”.

The same effect would have occurred if a Mercurian day was exactly equal to a Mercurian year, so before the beginning of the space age and radar observations, it was believed that the period of rotation of the planet around its axis was 58 days.

Mercury moves very slowly around its axis, but moves very quickly in its orbit. On Mercury, a solar day is equal to 176 Earth days, that is, during this time, thanks to the addition of orbital and axial movements, two “Mercurian” years have passed on the planet!

Atmosphere and temperature on Mercury

Thanks to spacecraft, it was possible to find out that Mercury has an extremely rarefied helium atmosphere, which contains an insignificant state of neon, argon and hydrogen.

As for the properties of Mercury itself, they are in many ways similar to the lunar ones - on the night side the temperature drops to -180 degrees Celsius, which is enough to freeze carbon dioxide and liquefy oxygen, on the day side it rises to 430, which is enough to melt lead and zinc . However, due to the extremely weak thermal conductivity of the loose surface layer, already at a depth of a meter the temperature stabilizes at plus 75.

This is due to the lack of a noticeable atmosphere on the planet. However, there is still some semblance of an atmosphere - from atoms emitted as part of the solar wind, mostly metallic.

Study and observation of Mercury

It is possible to observe Mercury, even without the help of a telescope, after sunset and before sunrise, however, certain difficulties arise due to the location of the planet; even during these periods it is not always noticeable.

When projected onto the celestial sphere, the planet is visible as a star-shaped object that does not move further than 28 degrees of arc from the Sun, with a greatly varying brightness - from minus 1.9 to plus 5.5 magnitude, that is, approximately 912 times. You can notice such an object at dusk only in ideal atmospheric conditions and if you know where to look. And the displacement of the “star” per day exceeds four degrees of arc - it was for this “speed” that the planet at one time received its name in honor of the Roman god of trade with winged sandals.

Near perihelion, Mercury comes so close to the Sun and its orbital speed increases so much that to an observer on Mercury the Sun appears to be moving backwards. Mercury is so close to the Sun that it is very difficult to observe.

In mid-latitudes (including Russia), the planet is visible only in the summer months and after sunset.

You can observe Mercury in the sky, but you need to know exactly where to look - the planet is visible very low above the horizon (lower left corner)

The temperature on the surface of Mercury varies significantly: from -180 C to dark side and up to +430 C on the sunny side. Moreover, since the planet’s axis almost never deviates from 0 degrees, even on the planet closest to the Sun (at its poles), there are craters whose bottoms have never been reached by the sun’s rays.

2. Mercury makes one revolution around the Sun in 88 Earth days, and one revolution around its axis in 58.65 days, which is 2/3 of one year on Mercury. This paradox is caused by the fact that Mercury is affected by the tidal influence of the Sun.

3. Mercury's magnetic field strength is 300 times less than the magnetic field strength of planet Earth; Mercury's magnetic axis is inclined to the axis of rotation by 12 degrees.

4. Mercury is the smallest of all the terrestrial planets; it is so small that it is inferior in size to the largest satellites of Saturn and Jupiter - Titan and Ganymede.

5. Despite the fact that the closest orbits to the Earth are Venus and Mars, Mercury has been closer to the Earth for a longer period of time than any other planet.

6. The surface of Mercury resembles the surface of the Moon - it, like the Moon, is dotted with a large number of craters. The biggest and important difference These two bodies are due to the presence on Mercury of a large number of jagged slopes - the so-called scarps, which extend for several hundred kilometers. They were formed by compression, which accompanied the cooling of the planet's core.

7. Perhaps the most noticeable detail on the surface of the planet is the Plain of Heat. This is a crater that got its name due to its location near one of the “hot longitudes”. 1300 km is the diameter of this crater. The body that hit the surface of Mercury in time immemorial must have had a diameter of at least 100 km.

8. The planet Mercury rotates around the Sun at an average speed of 47.87 km/s, making it the fastest planet in the Solar System.

9. Mercury is the only planet in the solar system that has Joshua effect. This effect looks like this: The Sun, if we observed it from the surface of Mercury, at a certain moment would have to stop in the sky, and then continue moving, but not from east to west, but on the contrary - from west to east. This is possible due to the fact that for approximately 8 days the speed of Mercury's rotational motion is less than the orbital speed of the planet.

10. Not so long ago, thanks to mathematical modeling, scientists came up with the idea that Mercury is not an independent planet, but a long-lost satellite of Venus. However, while there is no physical evidence, this is nothing more than a theory.

Space is a unique world in which not only cold, darkness and vacuum reign, but life is in full swing there far beyond the invisible horizon, new planets are born, young asteroids and comets appear. Today we know different Interesting Facts about the planet Mercury and the solar system, their diversity, uniqueness and pristine beauty.

Mercury is considered the smallest planet in our solar system, its dimensions practically do not exceed the size of the Moon. The diameter of Mercury's equator is 4879 kilometers.
Mercury is the only planet in the solar system that does not have its own satellites.
At certain points on the surface of Mercury, you can observe how at sunrise the Sun rises low above the horizon, after which it sets back and rises again. The same phenomenon occurs during sunset. This phenomenon is explained by the elliptical shape of Mercury's orbit and its leisurely rotation around its own axis.
Mercury makes a complete revolution around the Sun in 88 Earth days. In order to turn around its axis, Mercury requires 58.65 Earth days, this number of days is 2/3 of a year on a distant planet.
Mercury is the only planet in the solar system where sudden temperature changes are observed.. On the side of the planet, which is illuminated by the Sun, the air temperature reaches up to +430 degrees Celsius, while at the same time its opposite side is shrouded in night, and the air temperature can exceed -180 degrees Celsius. Therefore, the opinion that Mercury is the hottest planet is incorrect.
Mercury is characterized by such a phenomenon as the Joshua effect. The sun in the sky of this planet begins to move in a different direction, that is, the opposite, from west to east.
The duration of one day on the planet Mercury is equal to 59 Earth days, from this we can conclude that the year on this planet lasts no more than two days a year.
Mercury rotates very quickly around the Sun, which cannot be said about its speed of rotation around its axis.
Mercury has a magnetic field. In its center there is an iron core, with the help of which a magnetic field is formed, the strength of which is equal to 1% of the earth's. Despite their small sizes, on the surface of Mercury there is one of the largest craters in the solar system called Beethoven, whose diameter is 643 kilometers.
There are a large number of craters on the surface of Mercury, many of them are very tall. They were formed as a result of numerous collisions with passing comets and asteroids. Craters exceeding 250 km in diameter are called basins.
Man managed to visit the planet twice. Today, research is being conducted in Mercury's orbit thanks to the Messenger probe launched to its surface.
Until recently, people thought that Mercury had no atmosphere. But the rumors were refuted after the Messenger probe operating in orbit of the planet discovered thin layer gas near the surface of Mercury.
ABOUT mysterious planet Mercury was known in Ancient Rome and Greece. Scientists of that time gave the planet two names. During the day they saw a planet called Apollo, and at night they saw its reflection, which they called Hermes. Later, the Romans gave the planet the name of the god of the merchant - Mercury.
The crater Heat Plain is located on the surface of the planet.. This name was given to the crater due to its close proximity to “hot longitudes”. In cross-section, the dimensions of the crater are about 1300 km. There is an opinion that many centuries ago the surface of Mercury was damaged by a fallen body whose diameter exceeded 100 km.
The rotation speed of the planet Mercury is twice that of the planet Earth..

Compression < 0,0006 Equatorial radius 2439.7 km Average radius 2439.7 ± 1.0 km Circumference 15329.1 km Surface area 7.48×10 7 km²
0.147 Earth Volume 6.08272×10 10 km³
0.056 Earth Weight 3.3022×10 23 kg
0.055 Earth Average density 5.427 g/cm³
0.984 Earth Acceleration of free fall at the equator 3.7 m/s²
0,38 Second escape velocity 4.25 km/s Rotation speed (at equator) 10.892 km/h Rotation period 58,646 days (1407.5 hours) Rotation axis tilt 0.01° Right ascension at the North Pole 18 h 44 min 2 s
281.01° Declination at the North Pole 61.45° Albedo 0.119 (Bond)
0.106 (geom. albedo) Atmosphere Atmospheric composition 31.7% potassium
24.9% sodium
9.5%, A. oxygen
7.0% argon
5.9% helium
5.6%, M. oxygen
5.2% nitrogen
3.6% carbon dioxide
3.4% water
3.2% hydrogen

Mercury in natural color (Mariner 10 image)

Mercury- the planet closest to the Sun in the Solar System, orbits the Sun in 88 Earth days. Mercury is classified as an inner planet because its orbit is closer to the Sun than the main asteroid belt. After Pluto was deprived of its planetary status in 2006, Mercury acquired the title of the smallest planet in the solar system. Mercury's apparent magnitude ranges from −2.0 to 5.5, but it is not easily visible due to its very small angular distance from the Sun (maximum 28.3°). At high latitudes, the planet can never be seen in the dark night sky: Mercury is always hidden in the morning or evening dawn. The optimal time for observing the planet is morning or evening twilight during periods of its elongations (periods of Mercury's maximum distance from the Sun in the sky, occurring several times a year).

It is convenient to observe Mercury at low latitudes and near the equator: this is due to the fact that the duration of twilight there is shortest. In mid-latitudes it is much more difficult to find Mercury and only during the period of best elongations, and in high latitudes it is impossible at all.

Relatively little is known about the planet yet. The Mariner 10 apparatus, which studied Mercury in -1975, managed to map only 40-45% of the surface. In January 2008, the interplanetary station MESSENGER flew past Mercury, which will enter orbit around the planet in 2011.

In its physical characteristics, Mercury resembles the Moon and is heavily cratered. The planet has no natural satellites, but there is a very rarefied atmosphere. The planet has a large iron core, which is the source of a magnetic field in its totality that is 0.1 of the Earth’s. Mercury's core makes up 70 percent of the planet's total volume. The temperature on the surface of Mercury ranges from 90 to 700 (−180 to +430 °C). The solar side heats up much more than the polar regions and the far side of the planet.

Despite its smaller radius, Mercury still exceeds in mass such satellites of the giant planets as Ganymede and Titan.

The astronomical symbol of Mercury is a stylized image of the winged helmet of the god Mercury with his caduceus.

History and name

The oldest evidence of observations of Mercury can be found in Sumerian cuneiform texts dating back to the third millennium BC. e. The planet is named after the god of the Roman pantheon Mercury, analogue of Greek Hermes and Babylonian Naboo. The ancient Greeks of the time of Hesiod called Mercury "Στίλβων" (Stilbo, the Shining One). Until the 5th century BC. e. The Greeks believed that Mercury, visible in the evening and morning skies, were two different objects. In ancient India, Mercury was called Buddha(बुध) and Roginea. In Chinese, Japanese, Vietnamese and Korean, Mercury is called water star(水星) (in accordance with the ideas of the “Five Elements”. In Hebrew, the name of Mercury sounds like “Kohav Hama” (כוכב חמה) (“Solar Planet”).

Planet movement

Mercury moves around the Sun in a fairly elongated elliptical orbit (eccentricity 0.205) at an average distance of 57.91 million km (0.387 AU). At perihelion, Mercury is 45.9 million km from the Sun (0.3 AU), at aphelion - 69.7 million km (0.46 AU). At perihelion, Mercury is more than one and a half times closer to the Sun than at aphelion. The inclination of the orbit to the ecliptic plane is 7°. Mercury spends 87.97 days on one orbital revolution. The average speed of the planet's orbit is 48 km/s.

For a long time, it was believed that Mercury constantly faces the Sun with the same side, and one revolution around its axis takes the same 87.97 days. Observations of details on the surface of Mercury, carried out at the limit of resolution, did not seem to contradict this. This misconception was due to the fact that most favorable conditions for observing Mercury are repeated after a triple synodic period, that is, 348 Earth days, which is approximately equal to six times the rotation period of Mercury (352 days), therefore, approximately the same section of the planet’s surface was observed at different times. On the other hand, some astronomers believed that Mercury's day was approximately equal to Earth's. The truth was revealed only in the mid-1960s, when radar was carried out on Mercury.

It turned out that a Mercury sidereal day is equal to 58.65 Earth days, that is, 2/3 of a Mercury year. This commensurability of the periods of rotation and revolution of Mercury is a unique phenomenon for the Solar System. It is presumably explained by the fact that the tidal action of the Sun took away angular momentum and retarded the rotation, which was initially faster, until the two periods were related by an integer ratio. As a result, in one Mercury year, Mercury manages to rotate around its axis by one and a half revolutions. That is, if at the moment Mercury passes perihelion a certain point on its surface is facing exactly the Sun, then at the next passage of perihelion the exact opposite point on the surface will be facing the Sun, and after another Mercury year the Sun will again return to the zenith above the first point. As a result, a solar day on Mercury lasts two Mercury years or three Mercury sidereal days.

As a result of this movement of the planet, “hot longitudes” can be distinguished on it - two opposite meridians, which alternately face the Sun during Mercury’s passage of perihelion, and which, because of this, are especially hot even by Mercury standards.

The combination of planetary movements gives rise to another unique phenomenon. The speed of rotation of the planet around its axis is practically constant, while the speed of orbital motion is constantly changing. In the orbital region near perihelion, for approximately 8 days, the speed of orbital motion exceeds the speed of rotational motion. As a result, the Sun stops in the sky of Mercury and begins to move in the opposite direction - from west to east. This effect is sometimes called the Joshua effect, named after the main character of the Book of Joshua from the Bible, who stopped the movement of the Sun (Joshua, X, 12-13). For an observer at longitudes 90° away from the “hot longitudes,” the Sun rises (or sets) twice.

It is also interesting that although the closest orbits to Earth are Mars and Venus, it is Mercury that is most of the time the closest planet to Earth than any other (since the others move away at to a greater extent, without being so “tied” to the Sun).

physical characteristics

Comparative sizes of Mercury, Venus, Earth and Mars

Mercury is the smallest terrestrial planet. Its radius is only 2439.7 ± 1.0 km, which is smaller than the radius of Jupiter's moon Ganymede and Saturn's moon Titan. The mass of the planet is 3.3 × 10 23 kg. The average density of Mercury is quite high - 5.43 g/cm³, which is only slightly less than the density of Earth. Considering that the Earth is larger in size, the density value of Mercury indicates an increased content of metals in its depths. The acceleration of gravity on Mercury is 3.70 m/s². The second escape velocity is 4.3 km/s.

Kuiper Crater (just below center). Photo from MESSENGER spacecraft

One of the most noticeable features of the surface of Mercury is the Plain of Heat (lat. Caloris Planitia). This crater got its name because it is located near one of the “hot longitudes”. Its diameter is about 1300 km. Probably, the body whose impact formed the crater had a diameter of at least 100 km. The impact was so strong that the seismic waves, having passed through the entire planet and focused at the opposite point on the surface, led to the formation of a kind of rugged “chaotic” landscape here.

Atmosphere and physical fields

When flying spacecraft"Mariner 10" passing Mercury, it was established that the planet has an extremely rarefied atmosphere, the pressure of which is 5 × 10 11 times less than the pressure of the earth's atmosphere. Under such conditions, atoms collide more often with the surface of the planet than with each other. It consists of atoms captured from the solar wind or knocked out from the surface by the solar wind - helium, sodium, oxygen, potassium, argon, hydrogen. The average lifetime of a certain atom in the atmosphere is about 200 days.

Mercury has a magnetic field whose strength is 300 times less than the Earth's magnetic field. Mercury's magnetic field has a dipole structure and highest degree symmetrically, and its axis deviates only 2 degrees from the axis of rotation of the planet, which imposes a significant limitation on the range of theories explaining its origin.

Research

An image of a section of Mercury's surface taken by MESSENGER

Mercury is the least studied terrestrial planet. Only two devices were sent to study it. The first was Mariner 10, which flew past Mercury three times in -1975; the closest approach was 320 km. As a result, several thousand images were obtained, covering approximately 45% of the planet's surface. Further research from Earth showed the possibility of the existence of water ice in polar craters.

Mercury in art

In Boris Lyapunov's science fiction story "Nearest to the Sun" (1956), Soviet cosmonauts land on Mercury and Venus for the first time to study them.
Isaac Asimov's story "Mercury's Big Sun" (Lucky Starr series) takes place on Mercury.
Isaac Asimov's stories "Runaround" and "The Dying Night", written in 1941 and 1956 respectively, describe Mercury with one side facing the Sun. Moreover, in the second story, the solution to the detective plot is based on this fact.
In the science fiction novel The Flight of the Earth by Francis Karsak, along with the main plot, a scientific station for studying the Sun, located at the North Pole of Mercury, is described. Scientists live at a base located in the eternal shadow of deep craters, and observations are carried out from giant towers constantly illuminated by the luminary.
In Alan Nurse's science fiction story "Across the Sunny Side", the main characters cross the side of Mercury facing the Sun. The story was written in accordance with the scientific views of its time, when it was assumed that Mercury was constantly facing the Sun with one side.
In the anime animated series Sailor Moon, the planet is personified by the warrior girl Sailor Mercury, aka Ami Mitsuno. Her attack is based on the power of water and ice.
In Clifford Simak's science fiction story "Once Upon a Time on Mercury", the main field of action is Mercury, and the energy form of life on it - balls - surpasses humanity by millions of years of development, having long passed the stage of civilization.

Notes

Literature

Bronshten V. Mercury is closest to the Sun // Aksenova M.D. Encyclopedia for children. T. 8. Astronomy - M.: Avanta+, 1997. - P. 512-515. - ISBN 5-89501-008-3
Ksanfomality L.V. Unknown Mercury // In the world of science. - 2008. - № 2.