Mercury radius. Mercury's magnetic field

Mercury- the first planet of the solar system: description, size, mass, orbit around the sun, distance, characteristics, interesting facts, history of study.

Mercury- the first planet from the Sun and the smallest planet in the solar system. This is one of the most extreme worlds. It got its name in honor of the messenger of the Roman gods. It can be found without the use of instruments, which is why Mercury has been noted in many cultures and myths.

However, it is also a very mysterious object. Mercury can be observed in the morning and evening in the sky, and the planet itself has its own phases.

Interesting facts about the planet Mercury

Let's find out more interesting facts about the planet Mercury.

A year on Mercury is only 88 days long.

One solar day (the interval between noons) spans 176 days, and a sidereal day (axial rotation) spans 59 days. Mercury is endowed with the largest orbital eccentricity, and the distance from the Sun is 46-70 million km.

It is the smallest planet in the system

Mercury is one of the five planets that can be found without the use of tools. At the equator, it extends for 4879 km.

Ranks second in density

Each cm 3 is endowed with an indicator of 5.4 grams. But the Earth comes first, because Mercury is represented by heavy metals and rocks.

There are wrinkles

As the iron planetary core cooled and contracted, the surface layer became wrinkled. They are capable of stretching for hundreds of miles.

There is a molten core

Researchers believe that the iron core of Mercury is able to stay in a molten state. Usually in small planets, it quickly loses heat. But now they think that it contains sulfur, which lowers the melting point. The core covers 42% of the planetary volume.

Second in hotness

Although Venus lives further away, its surface stably holds the highest surface temperature due to the greenhouse effect. The day side of Mercury warms up to 427°C, and the nighttime temperature drops to -173°C. The planet is devoid of an atmospheric layer, therefore it is not able to provide a uniform distribution of heat.

most cratered planet

Geological processes help planets renew their surface layer and smooth out crater scars. But Mercury is deprived of such an opportunity. All of its craters are named after artists, writers and musicians. Impact formations exceeding 250 km in diameter are called basins. The largest is the Zhara Plain, stretching for 1550 km.

It was visited by only two devices

Mercury is too close to the Sun. Mariner 10 circled it three times in 1974-1975, displaying slightly less than half of the surface. In 2004 MESSENGER went there.

The name was given in honor of the messenger from the Roman divine pantheon

The exact date of the discovery of the planet is unknown, because the Sumerians wrote about it in 3000 BC.

There's an atmosphere (it seems)

Gravity is only 38% of Earth's, but this is not enough to keep a stable atmosphere (destroyed by solar winds). The gas comes out, but it is replenished by solar particles and dust.

Size, mass and orbit of the planet Mercury

With a radius of 2440 km and a mass of 3.3022 x 10 23 kg, Mercury considered the smallest planet in the solar system. In size, it reaches only 0.38 of the earth. It is also inferior in parameters to some satellites, but in terms of density it is in second place after the Earth - 5.427 g / cm 3. The bottom photo shows a comparison of the sizes of Mercury and the Earth.

This is the owner of the most eccentric orbit. The distance of Mercury from the Sun can vary from 46 million km (perihelion) to 70 million km (aphelion). From this, the nearest planets can also change. The average orbital velocity is -47322 km/s, so it takes 87.969 days to complete the orbital path. Below is a table of characteristics of the planet Mercury.

Physical characteristics of Mercury

Equatorial radius	2439.7 km
Polar radius	2439.7 km
Medium radius	2439.7 km
Great circle circumference	15,329.1 km
Surface area	7.48 10 7 km² 0.147 Earth
Volume	6.083 10 10 km³ 0.056 Earth
Weight	3.33 10 23 kg 0.055 Earth
Average density	5.427 g/cm³ 0.984 Earth
Acceleration free fall at the equator	3.7 m/s² 0.377g
first cosmic speed	3.1 km/s
Second space velocity	4.25 km/s
equatorial speed rotation	10.892 km/h
Rotation period	58,646 days
Axis Tilt	2.11' ± 0.1'
right ascension north pole	18 h 44 min 2 s 281.01°
declination of the north pole	61.45°
Albedo	0.142 (Bond) 0.068 (geom.)
Apparent magnitude	from −2.6 m to 5.7 m
Angular diameter	4,5" – 13"

The rotation speed of the axis is 10.892 km/h, so a day on Mercury lasts 58.646 days. This indicates that the planet is in a 3:2 resonance (3 axial rotations in 2 orbital rotations).

The eccentricity and slowness of rotation lead to the fact that the planet spends 176 days to return to its original point. So one day on the planet is twice as long as a year. It is also the owner of the lowest axial tilt - 0.027 degrees.

The composition and surface of the planet Mercury

Composition of Mercury 70% metal and 30% silicate materials. It is believed that its core covers approximately 42% of the total volume of the planet (earth - 17%). Inside there is a core of molten iron, around which a silicate layer is concentrated (500-700 km). The surface layer is a crust with a thickness of 100-300 km. On the surface you can see a huge number of ridges that stretch for kilometers.

Compared to other planets in the solar system, the core of Mercury has the largest amount of iron. It is believed that earlier Mercury was much larger. But due to impact with a large object, the outer layers collapsed, leaving the main body.

Some believe that the planet may have appeared in a protoplanetary disk before solar energy became stable. Then it should be twice as massive as the current state. When heated to 25000-35000 K, most of the rock could simply evaporate. Study the structure of Mercury in the photo.

There is one more assumption. The solar nebula could lead to an increase in the particles that pounced on the planet. Then the lighter ones departed and were not used in the creation of Mercury.

When viewed from afar, the planet resembles an earthly satellite. The same crater landscape with plains and traces of lava flows. But there is a greater variety of elements here.

Mercury formed 4.6 billion years ago and came under fire from an army of asteroids and debris. There was no atmosphere, so the impacts left noticeable traces. But the planet remained active, so the lava flows created the plains.

Craters range in size from small pits to basins hundreds of kilometers wide. The largest is Kaloris (Zhara Plain) with a diameter of 1550 km. The impact was so strong that it led to a lava eruption on the opposite planetary side. And the crater itself is surrounded by a concentric ring 2 km high. Approximately 15 large crater formations can be found on the surface. Take a close look at the diagram of Mercury's magnetic field.

The planet has a global magnetic field reaching 1.1% of the earth's strength. It is possible that the source is a dynamo, reminiscent of our Earth. It is formed due to the rotation of a liquid core filled with iron.

This field is enough to resist stellar winds and form the magnetospheric layer. Its strength is enough to keep the plasma from the wind, which causes surface weathering.

Atmosphere and temperature of the planet Mercury

Due to its proximity to the Sun, the planet warms up too much, so it is not able to save the atmosphere. But scientists noted a thin layer of variable exosphere, represented by hydrogen, oxygen, helium, sodium, water vapor and potassium. The overall pressure level is approaching 10-14 bar.

Without an atmospheric layer, solar heat does not accumulate, therefore, serious temperature fluctuations are noted on Mercury: on the sunny side - 427 ° C, and on the dark side it drops to -173 ° C.

However, the surface contains water ice and organic molecules. The fact is that the pole craters differ in depth and direct sunlight does not fall there. It is believed that 10 14 - 10 15 kg of ice can be found at the bottom. While there is no exact data on where the ice came from on the planet, but it may be a gift from fallen comets or it is due to degassing of water from the inner planetary part.

The history of the study of the planet Mercury

The description of Mercury is not complete without a history of research. This planet is available for observation without the use of instruments, therefore it appears in myths and ancient legends. The first records were found in the Mul Apin tablet, which is an astronomical and astrological Babylonian record.

These observations were made in the 14th century BC. and talk about the "dancing planet" because Mercury moves the fastest. In ancient Greece, it was called Stilbon (translated as "shine"). It was the messenger of Olympus. Then the Romans adopted this idea and gave the modern name in honor of their pantheon.

Ptolemy mentioned several times in his writings that the planets are capable of passing in front of the Sun. But he did not write down Mercury and Venus as examples, because he considered them too small and inconspicuous.

The Chinese called him Chen Xin ("Hour Star") and associated with water and a northern orientation. Moreover, in Asian culture, such an idea of \u200b\u200bthe planet is still preserved, which is even recorded as the 5th element.

For the Germanic tribes, there was a connection with the god Odin. Maya saw four owls, two of which were responsible for the morning, and the other two for the evening.

One of the Islamic astronomers wrote about the geocentric orbital path back in the 11th century. In the 12th century, Ibn Bajya noted the transit of two tiny dark bodies in front of the Sun. Most likely he saw Venus and Mercury.

The Indian astronomer of Kerala Somayaji in the 15th century created a partial heliocentric model, where Mercury made revolutions around the Sun.

The first view through a telescope falls on the 17th century. This was done by Galileo Galilei. He then carefully studied the phases of Venus. But his apparatus did not have enough power, so Mercury was left without attention. But the transit was noted by Pierre Gassendi in 1631.

Orbital phases were noticed by Giovanni Zupi in 1639. This was an important observation because it confirmed the rotation around the star and the correctness of the heliocentric model.

More accurate observations in the 1880s. provided by Giovanni Schiaparelli. He believed that the orbital journey takes 88 days. In 1934, Eugios Antoniadi created a detailed map of the surface of Mercury.

The first radar signal was beaten off by Soviet scientists in 1962. Three years later, the Americans repeated the experiment and fixed the axial rotation in 59 days. Ordinary optical observations failed to provide new information, but interferometers revealed the chemical and physical characteristics of the subsurface layers.

The first deep study of surface features was carried out in 2000 by the Mount Wilson Observatory. Most of the map was made using the Arecibo radar telescope, where the expansion reaches 5 km.

Exploration of the planet Mercury

Until the time of the first flight of unmanned vehicles, we did not know much about morphological characteristics. Mariner was the first to go to Mercury in 1974-1975. He approached three times and took a series of large-scale photos.

But the device had a long orbital period, so at each approach it approached the same side. So the map was only 45% of the total area.

At the first approach, it was possible to fix the magnetic field. Subsequent approaches have shown that it strongly resembles Earth, deflecting stellar winds.

In 1975 the craft ran out of fuel and we lost contact. However, Mariner 10 can still orbit the Sun and visit Mercury.

The second envoy was MESSENGER. He had to understand density, magnetic field, geology, core structure and atmospheric features. For this, special cameras were installed to guarantee the highest resolution, and spectrometers marked the constituent elements.

MESSENGER launched in 2004 and has completed three overflights since 2008, compensating for lost territory by Mariner 10. In 2011, he switched to an elliptical planetary orbit and began to take pictures of the surface.

After that, the next year-long mission started. The last maneuver took place on April 24, 2015. After that, the fuel ran out, and on April 30 the satellite crashed on the surface.

In 2016, ESA and JAXA teamed up to create BepiColombo, which should reach the planet in 2024. It has two probes that will study the magnetosphere as well as the surface in all wavelengths.

Of all the planets of the solar system known today, Mercury is the object of the least interest to the scientific community. This is explained primarily by the fact that a small star, burning dimly in the night sky, in fact turned out to be the least suitable in terms of applied science. The first planet from the Sun is a lifeless cosmic training ground, on which nature itself obviously trained in the process of the formation of the solar system.

In fact, Mercury can be safely called a real storehouse of information for astrophysicists, from which you can draw a lot of interesting data about the laws of physics and thermodynamics. Using the information received about this most interesting celestial object, one can get an idea of \u200b\u200bthe effect that our star has on the entire solar system.

What is the first planet in the solar system?

Today, Mercury is considered the smallest planet in the system. Since Pluto was excluded from the list of the main celestial bodies of our near space and transferred to the category of dwarf planets, Mercury has taken an honorable first place. However, this leadership did not add points. The place that Mercury occupies in the solar system leaves it out of the field of view of modern science. It's all because of the proximity to the sun.

Such an unenviable situation leaves an imprint on the behavior of the planet. Mercury at 48 km/s. rushes along its orbit, making a complete revolution around the Sun in 88 Earth days. It rotates around its own axis quite slowly - in 58.646 days, which gave astronomers a reason to consider Mercury for a long time turned to the Sun on one side.

With a high degree of probability, it was precisely this speed of the celestial body and its proximity to the central luminary of our solar system that became the reasons for giving the planet a name in honor of the ancient Roman god Mercury, who was also distinguished by his swiftness.

To the credit of the first planet of the solar system, even the ancients considered it an independent celestial body that revolves around our star. From this perspective, the academic data on the nearest neighbor of our luminary are curious.

Brief description and features of the planet

Of all the eight planets in the solar system, Mercury has the most unusual orbit. Due to the insignificant distance of the planet from the Sun, its orbit is the shortest, but in its shape it is a highly elongated ellipse. Compared to the orbital path of other planets, the first planet has the highest eccentricity - 0.20 e. In other words, the movement of Mercury resembles a giant cosmic swing. At perihelion, the impetuous neighbor of the Sun approaches it at a distance of 46 million km, glowing red hot. In aphelion, Mercury is given away from our star at a distance of 69.8 million km, having time to cool down a little in the vastness of space during this time.

In the night sky, the planet has a luminosity in a wide range from -1.9m to 5.5m, but its observation is very limited due to the proximity of Mercury to the Sun.

Such a feature of orbital flight easily explains the wide range of temperature differences on the planet, which is the most significant in the solar system. However, the main distinguishing feature of the astrophysical parameters of a small planet is the displacement of the orbit relative to the position of the Sun. This process in physics is called precession, and what causes it is still a mystery. In the 19th century, a table of changes in the orbital characteristics of Mercury was even compiled, but it was not possible to fully explain this behavior of a celestial body. Already in the middle of the 20th century, an assumption was made about the existence of a certain planet near the Sun, which affects the position of the orbit of Mercury. It is not possible to confirm this theory at the moment with technical means of observation using a telescope, due to the close location of the study area to the Sun.

The most appropriate explanation for this feature of the planet's orbit is to consider precession from the point of view of Einstein's theory of relativity. Mercury's preliminary orbital resonance was estimated as 1 to 1. In fact, it turned out that this parameter has a value of 3 to 2. The planet's axis is located at right angles to the orbital plane, and the combination of the rotation speed of the solar neighbor around its own axis with the orbital speed leads to a curious phenomenon . The luminary, having reached the zenith, begins to reverse, therefore, on Mercury, the sunrise and sunset occur in one part of the Mercury horizon.

As for the physical parameters of the planet, they are as follows and look rather modest:

the average radius of the planet Mercury is 2439.7 ± 1.0 km;
the mass of the planet is 3.33022 1023 kg;
Mercury's density is 5.427 g/cm³;
free fall acceleration at the Mercury equator is 3.7 m/s2.

The diameter of the smallest planet is 4879 km. Among the planets of the terrestrial group, Mercury is inferior to all three. The real giants compared to the small Mercury are Venus and the Earth, Mars is not much larger than the size of the first planet. The solar neighbor is inferior in size even to the satellites of Jupiter and Saturn, Ganymede (5262 km) and Titan (5150 km).

Relative to the Earth, the first planet of the solar system occupies a different position. The closest distance between the two planets is 82 million km, while the maximum distance is 217 million km. If you fly from Earth to Mercury, then the spacecraft can reach the planet faster than going to Mars or Venus. This is due to the fact that a small planet is often located closer to the Earth than its neighbors.

Mercury has a very high density, and in this parameter it is closer to our planet, surpassing Mars almost twice - 5.427 g / cm3 versus 3.91 g / cm2 for the Red Planet. However, the free fall acceleration of both planets, Mercury and Mars, is almost the same - 3.7 m/s2. For a long time, scientists believed that the first planet of the solar system was a satellite of Venus in the past, but obtaining accurate data on the mass and density of the planet debunked this hypothesis. Mercury is a completely independent planet, formed during the formation of the solar system.

With its modest size, only 4879 kilometers, but the planet is heavier than the Moon, and in density it surpasses such huge celestial bodies as the Sun, Jupiter, Saturn, Uranus and Neptune combined. However, such a high density did not provide the planet with other outstanding physical parameters, either in terms of geology or in terms of the state of the atmosphere.

Internal and external structure of Mercury

For all terrestrial planets, a characteristic feature is a solid surface.

This is due to the similarity of the internal structure of these planets. In terms of geology, Mercury has three classical layers:

the Mercurial crust, the thickness of which varies in the range of 100-300 km;
the mantle, which is 600 km thick;
iron-nickel core with a diameter of 3500-3600 km.

The crust of Mercury is like fish scales, where layers of rocks formed as a result of the geological activity of the planet in the early periods were layered on top of each other. These stratifications formed peculiar bulges, which are features of the relief. The rapid cooling of the surface layer led to the fact that the bark began to shrink like shagreen leather, losing its strength. Later, with the end of the geological activity of the planet, the Mercurial crust was subjected to a strong external influence.

Quite thin compared to the thickness of the crust, the mantle looks like, only 600 km. Such an insignificant thickness of the Mercury mantle speaks in favor of the theory according to which part of the planetary substance of Mercury was lost as a result of the collision of the planet with a large celestial body.

As for the core of the planet, there are many controversial points. The diameter of the core is ¾ of the diameter of the entire planet and has a semi-liquid state. Moreover, in terms of the concentration of iron in the core, Mercury is the undisputed leader among the planets of the solar system. The activity of the liquid core continues to influence the surface of the planet, forming on it peculiar geological formations - swelling.

For a long time, astronomers and scientists had little idea of the planet's surface based on visual observations. Only in 1974, with the help of the American space probe Mariner-10, did mankind for the first time have the opportunity to see the surface of its solar neighbor at close range. From the obtained images, it was possible to find out what the surface of the planet Mercury looks like. Judging by the pictures taken by Mariner 10, the first planet from the Sun is covered in craters. The largest crater "Kaloris" has a diameter of 1550 km. The areas between the craters are covered with Mercurian plains and rocky formations. In the absence of erosion, the surface of Mercury remained almost the same as it was at the dawn of the formation of the solar system. This was facilitated by the early cessation of active tectonic activity on the planet. Changes in the Mercury relief occurred only as a result of the fall of meteorites.

In its color scheme, Mercury strongly resembles the Moon, the same gray and faceless. The albedo of both celestial bodies is also almost the same, 0.1 and 0.12, respectively.

As for the climatic conditions on the planet Mercury, this is a harsh and cruel world. Despite the fact that under the influence of a nearby star the planet heats up to 4500 C, the heat is not retained on the Mercury surface. On the shadow side of the planetary disk, the temperature drops to -1700C. The reason for such sharp temperature fluctuations is the extremely rarefied atmosphere of the planet. In terms of physical parameters and density, the Mercury atmosphere resembles a vacuum, but even in such an environment, the planet's air layer consists of oxygen (42%), sodium and hydrogen (29% and 22%, respectively). Only 6% is helium. Less than 1% is accounted for by water vapor, carbon dioxide, nitrogen and inert gases.

It is believed that the dense air layer on the surface of Mercury disappeared as a result of the planet's weak gravitational field and the constant influence of the solar wind. The close proximity of the Sun contributes to the presence of a weak magnetic field on the planet. In many ways, this neighborhood and the weakness of the gravitational field contributed to the fact that Mercury has no natural satellites.

Mercury exploration

Until 1974, the planet was mainly observed with optical instruments. With the beginning of the space age, mankind got the opportunity to begin a more intensive study of the first planet of the solar system. Only two terrestrial spacecraft managed to reach the orbit of a small planet - the American Mariner-10 and Messenger. The first made a three-time flyby of the planet during 1974-75, approaching Mercury at the maximum possible distance - 320 km.

Scientists had to wait twenty long years until NASA's Messenger spacecraft set off for Mercury in 2004. Three years later, in January 2008, the automatic interplanetary station made the first flight around the planet. In 2011, the Messenger spacecraft safely took its place in the orbit of the planet and began to study it. Four years later, having worked out its resource, the probe fell to the surface of the planet.

The number of space probes sent to explore the first planet in the solar system, in comparison with the number of automatic vehicles sent to explore Mars, is extremely small. This is due to the fact that launching ships to Mercury is difficult from a technical point of view. To enter the Mercury orbit, it is necessary to perform a lot of complex orbital maneuvers, the implementation of which requires a large supply of fuel.

In the near future, it is planned to launch two automatic space probes at once, the European and Japanese space agencies. It is planned that the first probe will explore the surface of Mercury and its interior, while the second - a Japanese spacecraft - will study the atmosphere and magnetic field of the planet.

But after it was demoted from the status of "full-fledged" planets, the primacy passed to Mercury, about which our today's article is.

History of the discovery of the planet Mercury

The history of Mercury and our knowledge of this planet goes back to ancient times, in fact it is one of the first planets known to mankind. So Mercury was observed in ancient Sumer, one of the first developed civilizations on Earth. Among the Sumerians, Mercury was associated with the local god of writing, Nabu. The Babylonian and ancient Egyptian priests, concurrently excellent astronomers of the ancient world, also knew about this planet.

As for the origin of the name of the planet "Mercury", it already comes from the Romans, who named this planet in honor of the ancient god Mercury (in the Greek version of Hermes), the patron of trade, crafts and the messenger of other Olympic gods. Also, astronomers of the past sometimes poetically called Mercury the morning or evening dawn, according to the time of its appearance in the starry sky.

The god Mercury, after whom the planet was named.

Also, ancient astronomers believed that Mercury and its closest neighbor planet Venus revolve around the Sun, and not around the Earth. And now, in turn, it revolves around the Earth.

Features of the planet Mercury

Perhaps the most interesting feature of this small planet is the fact that it is on Mercury that the largest temperature fluctuations occur: since Mercury is closest to the Sun, during the day its surface warms up to 450 C. But on the other hand, Mercury does not have its own atmosphere and cannot retain heat, as a result, at night the temperature drops to minus 170 C, here the largest temperature difference in our solar system.

Mercury is only slightly larger than our Moon. Its surface is also similar to the moon, riddled with craters, traces of small asteroids and meteorites.

An interesting fact: about 4 billion years ago, a huge asteroid crashed into Mercury, the force of this impact can be compared with the explosion of a trillion megaton bombs. This impact left a giant crater on the surface of Mercury, about the size of the modern state of Texas, astronomers called it the Basins Caloris crater.

Also very interesting is the fact that there is real ice on Mercury, which is hidden in the depths of the craters there. Ice could have been brought to Mercury by meteorites, or even formed from water vapor that escapes from the planet's interior.

Another interesting feature of this planet is the decrease in its size. The decrease itself is believed by scientists to be caused by the gradual cooling of the planet, which occurs over millions of years. As a result of cooling, its surface is crushed and blade-shaped rocks are formed.

The density of Mercury is high, only our Earth is higher, in the center of the planet there is a huge molten core, which is 75% of the diameter of the entire planet.

With the help of the Mariner 10 research probe sent by NASA to the surface of Mercury, an amazing discovery was made - there is a magnetic field on Mercury. This was all the more surprising, since according to the astrophysical data of this planet: the speed of rotation and the presence of a molten core, there should not be a magnetic field there. Despite the fact that the strength of the magnetic field of Mercury is only 1% of the strength of the Earth's magnetic field, it is superactive - the magnetic field of the solar wind periodically enters the field of Mercury and, from interaction with it, strong magnetic tornadoes arise, sometimes reaching the surface of the planet.

The speed of the planet Mercury, at which it revolves around the Sun, is 180,000 km per hour. The orbit of Mercury is oval and strongly elongated epileptically, as a result of which it either approaches the Sun by 47 million kilometers, then moves away by 70 million kilometers. If we could observe the Sun from the surface of Mercury, then from there it would look three times larger than from Earth.

One year on Mercury is equal to 88 Earth days.

Mercury photo

We bring to your attention a photo of this planet.

Temperature on Mercury

What is the temperature on Mercury? Although this planet is located closest to the Sun, the championship of the warmest planet in the solar system belongs to its neighbor Venus, whose thick atmosphere, which literally envelops the planet, allows it to retain heat. As for Mercury, due to the absence of an atmosphere, its heat escapes and the planet both heats up quickly and cools down quickly, every day and every night there are simply huge temperature drops from +450 C during the day to -170 C at night. At the same time, the average temperature on Mercury will be 140 C, but this is not cold, not hot, the weather on Mercury leaves much to be desired.

Is there life on Mercury

As you probably guessed, with such temperature fluctuations, the existence of life is not possible.

Atmosphere of Mercury

We wrote above that there is no atmosphere on Mercury, although this statement can be argued, the atmosphere of the planet Mercury is not so absent, it is simply different and different from what we mean by the atmosphere itself.

The original atmosphere of this planet was dispersed 4.6 billion years ago due to the very weak Mercury, which simply could not hold it. In addition, proximity to the Sun and constant solar winds also did not contribute to the preservation of the atmosphere in the classical sense of the term. However, a faint atmosphere still exists on Mercury, and it is one of the most unstable and insignificant atmospheres in the solar system.

The composition of the atmosphere of Mercury includes helium, potassium, sodium, and also water vapor. In addition, the current atmosphere of the planet is periodically replenished from various diverse sources, such as solar wind particles, volcanic degassing, radioactive decay of elements.

Also, despite the small size and scanty density, the atmosphere of Mercury can be divided into as many as four sections: the lower, middle and upper layers, as well as the exosphere. The lower atmosphere contains a lot of dust, which gives Mercury a peculiar red-brown appearance, it warms up to high temperatures due to the heat that is reflected from the surface. The middle atmosphere has a jet similar to the earth's. The upper atmosphere of Mercury actively interacts with solar winds, which also heat it up to high temperatures.

The surface of the planet Mercury is a bare rock of volcanic origin. Billions of years ago, molten lava cooled and formed a rocky, gray surface. This surface is also responsible for the color of Mercury - dark gray, although due to dust in the lower layers of the atmosphere, one gets the feeling that Mercury is red-brown. Pictures of the surface of Mercury taken from the Messenger research probe are very reminiscent of the lunar landscape, the only thing is that there are no “lunar seas” on Mercury, while there are no Mercury scarps on the Moon.

Rings of Mercury

Does Mercury have rings? After all, many planets of the solar system, for example, and of course they are present. Alas, Mercury has no rings at all. Rings cannot exist on Mercury, again due to the proximity of this planet to the Sun, because the rings of other planets are formed from ice fragments, a piece of asteroids and other celestial objects, which near Mercury are simply melted by hot solar winds.

Moons of Mercury

Like the rings of satellites, Mercury does not have. This is due to the fact that not so many asteroids fly around this planet - potential satellite candidates when they come into contact with the planet's gravity.

Rotation of Mercury

The rotation of the planet Mercury is very unusual, namely, the orbital period of its rotation is shorter compared to the duration of rotation around its axis. This duration is less than 180 Earth days. While the orbital period is half that. In other words, Mercury goes through two orbits in its three revolutions.

How long is the flight to Mercury

At the closest point, the minimum distance from Earth to Mercury is 77.3 million kilometers. How long will it take modern spacecraft to overcome such a distance? NASA's fastest spacecraft to date, New Horizons, which was launched to Pluto, has a speed of about 80,000 kilometers per hour. It would take him about 40 days to fly to Mercury, which is relatively not so long.

The first spacecraft Mariner 10 launched to Mercury back in 1973 was not so fast, it took him 147 days to fly to this planet. Technology is improving, and perhaps in the near future it will be possible to fly to Mercury in a few hours.

Mercury is not easy enough to spot in the sky, as it "likes to play hide-and-seek" by literally "hiding" behind the Sun. However, astronomers of antiquity knew about it. This is explained by the fact that in those distant times the sky was darker due to the lack of light pollution, and the planet was visible much better.
The shift in Mercury's orbit helped confirm Albert Einstein's famous theory of relativity. In short, she tells how the light of a star changes when another planet revolves around it. Astronomers reflected a radar signal from Mercury, and the path of this signal coincided with the predictions of general relativity.
The magnetic field of Mercury, the very existence of which is very mysterious, in addition to everything else, it also differs at the poles of the planet. At the south pole it is more intense than at the north.

Mercury video

And in conclusion, an interesting documentary about the flight to the planet Mercury.

Mercury - the smallest planet in, is at the closest distance from the Sun, belongs to the terrestrial planets. The mass of Mercury is about 20 times less than that of the earth, and the planet has no natural satellites. According to scientists, the planet has a frozen iron core, which occupies 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 a collision with fragments that have remained since the formation of the solar system about 4 billion years ago. The surface of the planet 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 of 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 is 3476 km for the Moon, 4878 for Mercury. A day on Mercury is about 58 Earth days, or exactly 2/3 of a Mercury year. Another curious fact of the “lunar” similarity is connected with this - from the Earth, Mercury, like the Moon, always sees only the “front side”.

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

Mercury moves very slowly around its axis, but it moves very quickly in orbit. On Mercury, a solar day is equal to 176 Earth days, that is, during this time, due to the addition of orbital and axial movements, two "Mercurian" years have time to pass 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 actual properties of Mercury, they are in many ways similar to those of the moon - on the night side the temperature drops to -180 degrees Celsius, which is enough to freeze carbon dioxide and liquefy oxygen, on the daytime 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 absence 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.

In the projection on the celestial sphere, the planet is visible as a star-shaped object that does not depart from the Sun further than 28 degrees of arc, with a greatly varying brightness - from minus 1.9 to plus 5.5 magnitude, that is, about 912 times. It is possible to 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 the 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 the Sun moves backward for an observer on Mercury. Mercury is so close to the Sun that it is very difficult to observe it.

In mid-latitudes (including Russia), the planet is noticeable 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 on the dark side to +430 C on the sunny side. At the same time, since the axis of the planet almost does not deviate from 0 degrees, even on the planet closest to the Sun (at its poles), there are craters, the bottom of which the sun's rays never reached.

2. Mercury makes one revolution around the Sun in 88 Earth days, and around its axis one revolution 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 the planet Earth, the magnetic axis of Mercury is inclined to the axis of rotation by 12 degrees.

4. Mercury is the smallest of all the planets of the terrestrial group, 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 Venus and Mars are closest to the Earth in terms of their orbits, Mercury is 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 most important difference between these two bodies is 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. Almost 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. A body that hit the surface of Mercury in ancient times must have had a diameter of at least 100 km.

8. Around the sun, the planet Mercury rotates at an average speed of 47.87 km / s, which makes 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 were to observe 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 vice versa - from west to east. This is possible as a result of the fact that for about 8 days the rotational speed of Mercury is less than the orbital speed of the planet.

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

Space is a unique world in which not only cold, darkness and vacuum reign, life is in full swing far beyond the invisible horizon, new planets are born, young asteroids and comets appear. Today, various interesting facts are known 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 size practically does 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, one 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 unhurried rotation around its own axis.
Mercury completes one revolution around the Sun in 88 Earth days.. It takes 58.65 Earth days for Mercury to rotate around its axis, this number of days is 2/3 of a year on a distant planet.
Mercury is the only planet in the solar system that experiences extreme temperature fluctuations.. On the side of the planet, which is brightened by the Sun, the air temperature reaches up to +430 degrees Celsius, at the same time, its opposite side is shrouded at night, and the air temperature can exceed -180 degrees Celsius. Therefore, the opinion that Mercury is the hottest planet is incorrect.
Mercury has a phenomenon known 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.
One day on the planet Mercury is 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 rotation speed around its axis..
Mercury has a magnetic field. In its center 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 its small size, on the surface of Mercury is one of the largest craters in the solar system called Beethoven, whose diameter is 643 kilometers.
There are many craters on the surface of Mercury., many of which are very high. They were formed as a result of numerous collisions with comets and asteroids flying by. Craters larger than 250 km in diameter are called basins.
Man managed to visit the planet twice. Today, research is underway in the orbit of Mercury thanks to the Messenger probe launched on its surface.
Until recently, people thought that Mercury had no atmosphere.. But the rumors were debunked after the Messenger probe, operating in orbit around the planet, detected a thin layer of gas near the surface of Mercury.
The 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 Plain of Heat 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 size of the crater is about 1300 km. There is an opinion that many centuries ago the surface of Mercury was damaged by a fallen body, the size of which exceeded 100 km in diameter.
The rotation of the planet Mercury is twice that of the planet Earth..