Characteristics of the planet:

• Distance from the Sun: 57.9 million km
• Planet diameter: 4878 km
• Day on the planet: 58 days 16 hours*
• Year on the planet: 88 days*
• t° on the surface: from -180°C to +430°C
• Atmosphere: almost not present
• Satellites: doesn't have

* period of rotation around its own axis (in Earth days)
**period of orbit around the Sun (in Earth days)

Mercury is the eighth largest planet and closest to the Sun, with an average distance of 0.387 AU (astronomical units) or 57,910,000 kilometers. The planet's mass is 3.30e23 kg, and its diameter is 4,880 km (only Pluto is smaller).

Presentation: planet Mercury

Internal structure

In the center of the planet there is a metal core, similar to the Earth’s, the only difference is in size. If the earth's core occupies only 17% of the planet's volume, then Mercury's occupies 42% of the volume.

Around the core there is a layer of mantle - 500-700 kilometers of silicate rock. The next layer is the crust, which is approximately 100-300 kilometers thick. The top layer of the planet has a lot of damage, most scientists adhere to the theory that they were caused by the slow cooling of Mercury.

Atmosphere and surface

The atmosphere of Mercury is very rarefied and is practically equivalent to a vacuum. Compound:

• hydrogen (70 atoms per 1 cm³);
• helium (4,500 atoms per 1 cm³).

Due to the almost zero atmosphere and proximity to the Sun, the temperature on the surface of the planet fluctuates between -180....+440 °C. The surface resembles the lunar surface - many craters (from collisions with asteroids), and mountains up to 4 km high (lunar ones can be one and a half times higher).

Unlike the Earth's satellite, on the far side of Mercury there are swellings that were formed under the influence of solar tides. There are also high ledges, whose length can reach several hundred kilometers.

The name of the planet was given by the ancient Romans, who revered the god Mercury as the patron of thieves, travelers and traders. However, it is believed that the first planet from the Sun was known as early as 3000 BC. (from the time of the Samaritans).

In Ancient Greece, she was called by two names at once - Apollo (god of sunlight, patron of arts and science) in the morning and Hermes (nimble messenger of the gods) in the evening. Moreover, the Greeks did not know that they were seeing the same planet.

For a long time, astronomers could not understand the movement of Mercury across the sky, and all because of the anomalous precession of its orbit. Newtonian mechanics was in no way suitable for explaining the too elongated orbit: perihelion = 46 million km from the Sun, aphelion = 70 million km. Scientists of the 19th century even believed that some other planet (sometimes called Vulcan) was moving close to Mercury, which influenced its orbit. It became possible to correctly predict the movement of the planet only after Einstein discovered his General Theory of Relativity.

Exploring the planet

The study of Mercury is very complicated due to its close location to the Sun; it is impossible to obtain high-quality images from the American Hubble Telescope.

Only one interplanetary station approached the planet - Mariner 10, which made three flybys in 1974-1975. It was possible to map only 45% of the planet.

Radar observations were also carried out, but these data relate more to theory than to hard facts. Thus, a similar study showed the presence of frozen water at the north pole of Mercury (Mariner did not map this area).

Mercury is the first celestial body from the Sun in our planetary system. The planet was named Mercury in honor of the ancient Greek god - the patron of trade and enrichment, the son of Jupiter himself. A brief description of the planet Mercury will be presented in the article. You will also get acquainted with the history of its discovery, the role played by this planet in astrology, and interesting facts about it.

History of discovery and research

The exact date of the discovery of Mercury is difficult to determine. It is reliably known that they knew about it already in Ancient Babylon. This is evidenced by collections of astrological tables dating back to the 15th century BC, in which the planet appears under the name Mul apin (“jumping”). She was patronized by the god of wisdom and calligraphy Nanu. Scientists in Ancient China and India studied Mercury.

During Antiquity, the ancient Greeks knew this celestial body under the name Hermaon (Hermes), and the Romans knew Mercury, the god corresponding to Hermes from their pantheon. As you can see, in all cases the planet owes its names to its rapid movement across the sky.

Research on its movement has also been carried out since ancient times. Thus, Claudius Ptolemy (c. 100-170) wrote about the possibility of Mercury passing across the solar disk, which will be discussed below, in the late Hellenistic era.

In the Middle Ages, an Arab astronomer named Az-Zarqali described the features of the planet's orbit. Another scientist, Ibn Bajja, in the 12th century described the passage of two planets across the solar disk. Presumably these were Mercury and Venus.

The first scientist to observe Mercury through a telescope was Galileo Galilei. He was able to detect them, but did not detect them on Mercury. His telescope was not powerful enough.

In general, due to the fact that Mercury is the least distant planet from the Sun, it is still the least studied in the solar system. There, many of its parameters were determined incorrectly already in the 19th century. There were even oddities: for example, one of the researchers allegedly saw mountains about 20 km high on Mercury.

Currently, in addition to visual methods, radio telescopic and radar methods are used to study Mercury. However, not all funds are available. For example, research using spacecraft is difficult due to the proximity of Mercury to the Sun.

Education of the planet

The nebular hypothesis is the main one for scientists when it comes to the formation of planets in the solar system. As for Mercury, there is also an assumption regarding it that in the past it was a satellite of Venus, but was subsequently “lost” by this planet and began to move independently around the central star.

Planet parameters. Weight, dimensions, surface

What are the most important features to note in the characteristics of a planet? Mercury, Venus, Earth, Mars belong to the so-called terrestrial group. It includes solid celestial bodies of relatively small diameter compared to the gas giants Jupiter, Saturn, Uranus and Neptune. They have similar characteristics. And the planets Neptune and Mercury, for example, are complete opposites in many respects.

Mercury is the smallest of these celestial bodies. Its diameter is less than 0.4 Earth's (about 4880 km). The physical characteristics of the planet Mercury and its description indicate that it is smaller in size than the two largest satellites of the planets of the Solar System - Titan, a satellite of Saturn, and Jupiter. However, Mercury is nevertheless an independent celestial body, rotating in an elliptical orbit around a central star. However, its mass is still greater than that of the two mentioned small celestial bodies: approximately 3.3 x 10 23 kg (this is approximately 0.55 of Earth’s).

The surface of the planet has clear traces of long-standing volcanic activity, earthquakes and impacts of other cosmic bodies. Scientists suggest that Mercury suffered its last period of intense meteorite fall about 3.8 billion years ago.

Structure, density

Inside Mercury, according to scientists, like inside the Earth, there is a heavy iron core. Its mass is just over 0.8 times the mass of the entire planet. The average density of Mercury is almost equal to the average density of the Earth. Scientists believe this indicates that the planet is rich in metals. There is a hypothesis that at the dawn of the formation of the Solar system, Mercury was more similar to the Earth, but, colliding with the so-called planetesimal - a celestial body that revolves around a protostar and accumulates its own mass at the expense of other celestial bodies and cosmic dust, it lost a significant part of the matter, retaining almost one core.

Temperature, pressure, atmosphere

The contrast between temperatures on the solar and shadow sides of Mercury is enormous. The difference is 240 degrees Celsius (from -190 to +430). The pressure on the surface of the planet is 5 x 10 11 times less than that on Earth. The atmosphere is very rarefied, it is practically absent. Its main part is oxygen (42%), sodium (29%), hydrogen (22%). In addition to them, there are helium, water, carbon dioxide, inert gases, etc. The planet's own gravity and magnetic field are not enough to maintain a constant atmosphere. The average “life” of atoms in it is about 200 days. Basically, these are atoms that were “knocked out” by the solar wind from the surface of the planet or captured from the wind itself by Mercury.

Planet movement

Mercury revolves around the Sun faster than other planets. Its year lasts only 88 Earth days. The orbit is highly elongated, and at its most distant point the planet is 1.5 times farther from the Sun than at its closest point. The average speed of movement of a celestial body in orbit is 48 km per second.

Change of seasons

There are no seasons as such in our understanding on the planet, since the axis of rotation of Mercury is located almost perpendicular to the plane of its orbit. As a result, the polar regions are almost not illuminated by the Sun. Telescope research has suggested that these latitudes may contain extensive glaciers that are difficult to see from Earth because they are covered in dust. Presumably their thickness can be about two meters.

Transit of a planet across the solar disk

This is a curious phenomenon of some interest to astronomy enthusiasts. An observer on Earth can see Mercury as a tiny dark dot crossing the solar disk. The transit of Mercury can be observed in May or November. It usually lasts about seven hours. Due to the peculiarities of the planet's parameters, such as a higher speed of movement and proximity to the Sun, it happens more often than the transit of Venus. The last transit of Mercury was observed in 2016, on May 9. Astronomers will see the next one in 2019, on November 11.

Scientists have calculated that it is possible for both planets, Mercury and Venus, to pass simultaneously across the solar disk, but this phenomenon is so rare that it happens once every few hundred thousand years. So, it took place about 350 thousand years ago, and the next time will be in 69,163. And after 11,427 years, in 13,425, these luminaries will cross the solar disk within one day, with an interval of only 16 hours.

This interesting phenomenon was first recorded in 1631, on November 7, by the French philosopher, mathematician, astronomer and Catholic priest Pierre Gassendi.

Here are some interesting and unusual facts about this celestial body:

Influence of the planet Mercury in astrology

The astrological characteristics of this celestial body indicate that Mercury is traditionally considered the planet responsible for human mental abilities, as well as eloquence, openness and a tendency to communicate, and the assimilation of information. She patronizes scientists, speakers and merchants. The latter, having a strong influence of Mercury in the horoscope, acquire incredible eloquence, which allows them to sell goods profitably.

What other effects does the planet Mercury have in astrology? The characteristics of a person who has experienced its positive influence will include such parameters as the ability to think quickly and clearly, move quickly, be mobile and get a lot done. Mercury patronizes the voice, and therefore not only lecturers and speakers, but also singers. People whose horoscope has a strong positive influence of Mercury sing beautifully and love music and dancing. They are smart and quick-witted, brave and resourceful, agile and fast.

The negative influence of the planet gives rise to a person’s sarcastic attitude towards others, bilious, evil irony. Such people are not only inventive, but also cunning. They are resourceful and dishonest, and often become scammers. Counterfeiters and document forgers are people who have experienced the negative influence of Mercury.

In the birth chart, the planet, as in life, is usually located near the Sun - in the same sign or in a neighboring one.

Finally

The article gave a brief description of the planet Mercury - its physical parameters, features of rotation around the Sun and its own axis. The influence of the planet on personality according to astrology was also considered, and interesting facts about it were given. This celestial body, like other planets, is fraught with many mysteries, but sooner or later, thanks to the achievements of science, they will certainly be revealed, and the characteristics of Mercury will be replenished with new data.

When you look at images of Mercury, it looks like an airless and lifeless cosmic body. But you might be surprised to know that it has its own atmosphere.

Atmosphere of the planet

Of course, it is not as powerful as on Earth and even less than on Mars. But the planet has it, and is currently being studied by astronomers and the MESSENGER spacecraft.

The gaseous envelope, if there was one, dissipated completely soon after the planets formed about 4.6 billion years ago. This could have happened due to low gravity, as well as due to its close location to the Sun, which “blown it away” with its solar wind. Currently, it is practically invisible.

What does it consist of?

This rarefied shell consists of oxygen, hydrogen, helium, sodium, potassium and water vapor.

Astronomers believe that it is constantly replenished from various sources: solar wind particles, volcanic degassing, radioactive decay of elements on the surface of Mercury and cosmic dust and debris that the planet encounters on its way. Without these replenishment sources, it would be lost relatively quickly due to the solar wind.

Atmospheric composition:

Oxygen 42.0%
Sodium 29.0%
Hydrogen 22.0%
Helium 6%
Potassium 0.5%
The remaining 0.5% (krypton, methane, water vapor, nitric oxide, etc.)

In 2008, NASA's MESSENGER spacecraft discovered water vapor in it. This water is believed to be formed when hydrogen and oxygen atoms meet in the atmosphere.

The presence of water vapor indicates that water ice exists somewhere on the surface. Deposits of water ice were discovered at the poles of the planet, where the bottom of the craters is never illuminated by the light of the Sun, you can read more. Methane is believed to come from volcanism, geothermal processes and hydrothermal activity. Methane is an unstable gas and requires a constant and very active source, because methane is destroyed in less than a year.

Structure

Despite its small size, it was divided into four layers. These layers are the lower, middle, upper and exosphere. The lower layers are a fairly warm region (about 210 K). The lower layers are heated by dust in the air (1.5 microns in diameter) and thermal radiation from the surface.

Dust gives it a brown tint.

In the middle part of the atmosphere, there are air currents, like on Earth. The upper layers are heated by the solar wind and the temperature there is much higher than on the surface. The exosphere begins approximately 200 km from the surface and has no clear boundaries, it simply smoothly passes into space.

Mercury's magnetic field helps to hold it. While gravity pulls gases toward the surface, the magnetic field helps contain solar winds around the planet, much like on Earth. The magnetosphere allows it to maintain its shape.

The atmosphere is one of the weakest in the Solar System, the pressure is ~10*-15 bar.

The solar wind constantly blows it out, and sources on the planet constantly replenish it. I hope that the MESSENGER spacecraft, which entered orbit around the planet, will help find sources of replenishment and expand our knowledge about the planet.

	· · ·

Photo taken from the MESSENGER spacecraft.

The planet Mercury is the closest planet to the Sun. It is located at a distance of only 58 million km from our star (for comparison, from Earth to the Sun is 150 million km). Like all planets, It is named after a Roman god, in this case the Roman god of trade - just like the ancient Greek god Hermes.

Its diameter is only 4879 km, making it the smallest planet in the solar system. It is even smaller than the moons Ganymede and Titan. But it has a metallic core that makes up almost half the volume of the planet. This gives it greater mass and stronger gravity than one would expect. On Mercury, your weight would be 38% of your weight on Earth.

Orbit

Mercury revolves around the Sun in a highly elongated elliptical orbit.

At its closest point, it approaches the Sun at 46 million km, and then moves away to 70 million km. It takes the planet only 88 days to orbit the Sun.

At first glance, Mercury is quite similar to our Moon. It has a surface covered with craters, as well as ancient lava flows. The largest crater is the Caloris Basin, almost 1300 km across. Like our Moon, it has no discernible atmosphere. But below the surface is very different from the Moon. It has a huge core of iron surrounded by a thick layer of mantle rocks and a thin crust. gravity on the planet is 1/3 of Earth's.

It rotates slowly around its axis, completing one revolution every 59 days.

Atmosphere

It is very rarefied and consists of captured particles of the Solar wind. Without an atmosphere, it cannot retain heat from the Sun. The side that faces the Sun heats up to a temperature of 450 °C, while the shadow side cools to -170 °C.

Study

BepiColumbo, which was launched to explore the planet

The first spacecraft to reach Mercury was Mariner 10, which flew past the planet in 1974. He managed to photograph about half of the planet's surface over several flybys. Then in 2004 NASA launched the MESSENGER spacecraft mission. At the moment, the spacecraft has entered orbit and is studying it in great detail.

If you want to see it without a telescope, it is difficult to do because the planet is in the bright rays of the Sun most of the time.

When visible, you can see it in the west just after sunset, or in the east before sunrise. In a telescope, the planet has phases like the Moon, depending on its position in its orbit.

So, what is the planet Mercury and what is so special about it that makes it different from other planets? Probably, first of all, it’s worth listing the most obvious things that can be easily gleaned from different sources, but without which it will be difficult for a person to get the overall picture.

Currently (after Pluto was demoted to dwarf planets) Mercury is the smallest of the eight planets in our solar system. Also, the planet is at the closest distance from the Sun, and therefore rotates around our star much faster than the other planets. Apparently, it was precisely the latter quality that served as the reason to name it in honor of the fastest-footed messenger of the Gods named Mercury, an extraordinary character from the legends and myths of Ancient Rome, possessing phenomenal speed.

By the way, it was the ancient Greek and Roman astronomers who more than once called Mercury both the “morning” and “evening” star, although for the most part they knew that both names correspond to the same cosmic object. Even then, the ancient Greek scientist Heraclitus pointed out that Mercury and Venus rotate around the Sun, and not around.

Mercury today

Today, scientists know that due to Mercury's close proximity to the Sun, temperatures on its surface can reach up to 450 degrees Celsius. But the lack of an atmosphere on this planet does not allow Mercury to retain heat and on the shadow side the surface temperature can drop sharply to 170 degrees Celsius. The maximum temperature difference between daytime and nighttime on Mercury turned out to be the highest in the Solar System - more than 600 degrees Celsius.

In size, Mercury is slightly larger than the Moon, but at the same time much heavier than our natural satellite.

Despite the fact that the planet has been known to people since time immemorial, the first image of Mercury was obtained only in 1974, when the Mariner 10 spacecraft transmitted the first images in which it was possible to make out some features of the relief. After this, a long-term active phase began to study this cosmic body, and several decades later, in March 2011, a spacecraft called Messenger reached the orbit of Mercury. after which, finally, humanity received answers to many questions.

The atmosphere of Mercury is so thin that it practically does not exist, and the volume is about 10 to the fifteenth power less than the dense layers of the Earth's atmosphere. Moreover, the vacuum in the atmosphere of this planet is much closer to a true vacuum if we compare it with any other vacuum created on Earth using technical means.

There are two explanations for the lack of atmosphere on Mercury. Firstly, this is the density of the planet. It is believed that with a density of only 38% of the Earth's density, Mercury is simply not able to retain much of the atmosphere. Secondly, the proximity of Mercury to the Sun. Such a close distance to our star makes the planet most susceptible to the influence of solar winds, which remove the last remnants of what can be called an atmosphere.

However, no matter how scarce the atmosphere on this planet is, it still exists. According to the NASA space agency, its chemical composition consists of 42% oxygen (O2), 29% sodium, 22% hydrogen (H2), 6% helium, 0.5% potassium. The remaining insignificant part consists of molecules of argon, carbon dioxide, water, nitrogen, xenon, krypton, neon, calcium (Ca, Ca +) and magnesium.

It is believed that the rarefied atmosphere is due to the presence of extreme temperatures on the planet's surface. The lowest temperature can be about -180 °C, and the highest approximately 430 °C. As mentioned above, Mercury has the largest range of surface temperatures of any planet in the Solar System. The extreme maxima present on the side facing the Sun are precisely the result of an insufficient atmospheric layer that is not able to absorb solar radiation. By the way, the extreme cold on the shadow side of the planet is due to the same thing. The absence of a significant atmosphere does not allow the planet to retain solar radiation and heat very quickly leaves the surface, freely escaping into outer space.

Until 1974, the surface of Mercury remained largely a mystery. Observations of this cosmic body from Earth were very difficult due to the proximity of the planet to the Sun. It was possible to see Mercury only before dawn or immediately after sunset, but on Earth at this time the line of visibility is significantly limited by the too dense layers of our planet’s atmosphere.

But in 1974, after a magnificent three-time flyby of the surface of Mercury by the Mariner 10 spacecraft, the first fairly clear photographs of the surface were obtained. Surprisingly, despite significant time constraints, the Mariner 10 mission photographed almost half of the planet's entire surface. As a result of analyzing observational data, scientists were able to identify three significant features of the surface of Mercury.

The first feature is the huge number of impact craters that gradually formed on the surface over billions of years. The so-called Caloris basin is the largest of the craters, with a diameter of 1,550 km.

The second feature is the presence of plains between the craters. It is believed that these smooth areas of the surface were created by the movement of lava flows across the planet in the past.

And finally, the third feature is the rocks, scattered across the entire surface and reaching from several tens to several thousand kilometers in length and from one hundred meters to two kilometers in height.

Scientists especially emphasize the contradiction of the first two features. The presence of lava fields indicates that there was once active volcanic activity in the planet's historical past. However, the number and age of craters, on the contrary, indicate that Mercury was geologically passive for a very long time.

But the third distinctive feature of Mercury's surface is no less interesting. It turned out that the hills are formed by the activity of the planet’s core, which results in the so-called “bulging” of the crust. Similar bulges on Earth are usually associated with the displacement of tectonic plates, while the loss of stability of Mercury's crust occurs due to the contraction of its core, which is gradually compressed. The processes occurring at the core of the planet lead to compression of the planet itself. Recent calculations by scientists indicate that the diameter of Mercury has decreased by more than 1.5 kilometers.

Structure of Mercury

Mercury is made up of three distinct layers: the crust, the mantle, and the core. The average thickness of the planet's crust, according to various estimates, ranges from 100 to 300 kilometers. The presence of the previously mentioned bulges on the surface, whose shape resembles those of the earth, indicates that, despite being sufficiently hard, the crust itself is very fragile.

The estimated thickness of Mercury's mantle is about 600 kilometers, indicating that it is relatively thin. Scientists believe that it was not always so thin and that in the past there was a collision of the planet with a huge planetesmial, which led to the loss of significant mass of the mantle.

The core of Mercury has become the subject of a great deal of research. It is believed to be 3,600 kilometers in diameter and has some unique properties. The most interesting property is its density. Considering that the planetary diameter of Mercury is 4878 kilometers (it is smaller than the satellite Titan, whose diameter is 5125 kilometers, and the satellite Ganymede with a diameter of 5270 kilometers), the density of the planet itself is 5540 kg/m3 with a mass of 3.3 x 1023 kilograms.

So far, there is only one theory that has attempted to explain this feature of the planet's core, and has cast doubt on whether Mercury's core is actually solid. Having measured the characteristics of the bounce of radio waves from the surface of the planet, a group of planetary scientists came to the conclusion that the planet’s core is actually liquid and this explains a lot.

Mercury's orbit and rotation

Mercury is much closer to the Sun than any other planet in our system and, accordingly, it requires the shortest time to orbit. A year on Mercury is only about 88 Earth days.

An important feature of Mercury's orbit is its high eccentricity compared to other planets. Additionally, of all the planetary orbits, Mercury's orbit is the least circular.
This eccentricity, along with the lack of a significant atmosphere, explains why Mercury's surface experiences the widest range of temperature extremes in the Solar System. Simply put, Mercury's surface heats up much more when the planet is at perihelion than at aphelion, because the difference in distance between these points is too great.

The orbit of Mercury itself is an excellent example of one of the leading processes of modern physics. We are talking about a process called precession, which explains the shift in Mercury's orbit relative to the Sun over time.

Despite the fact that Newtonian mechanics (i.e. classical physics) predicts the rates of this precession in great detail, the exact values ​​have never been determined. This became a real problem for astronomers in the late nineteenth and early twentieth centuries. Many concepts have been formulated to explain the differences between theoretical interpretations and actual observations. According to one theory, it was even suggested that there is an unknown planet whose orbit is closer to the Sun than that of Mercury.

However, the most plausible explanation was found after Einstein's general theory of relativity was published. Based on this theory, scientists were finally able to describe the orbital precession of Mercury with sufficient accuracy.

Thus, for a long time it was believed that Mercury's spin-orbit resonance (the number of revolutions in its orbit) was 1:1, but it was eventually proven that it was actually 3:2. It is thanks to this resonance that a phenomenon is possible on the planet that is impossible on Earth. If an observer were on Mercury, he would be able to see that the Sun rises to the highest point in the sky, and then “turns on” the reverse stroke and descends in the same direction from which it rose.

1. Mercury has been known to mankind since ancient times. Although the exact date of its discovery is unknown, the first mention of the planet is believed to have appeared around 3000 BC. among the Sumerians.
2. A year on Mercury is 88 Earth days long, but a Mercury day is 176 Earth days long. Mercury is almost completely blocked by tidal forces from the Sun, but over time the planet slowly rotates around its axis.
3. Mercury orbits the Sun so quickly that some early civilizations believed it was actually two different stars, one appearing in the morning and the other in the evening.
4. With a diameter of 4.879 km, Mercury is the smallest planet in the solar system and is also one of the five planets that can be seen in the night sky with the naked eye.
5. After Earth, Mercury is the second densest planet in the solar system. Despite its small size, Mercury is very dense, as it consists mainly of heavy metals and stone. This allows us to classify it as a terrestrial planet.
6. Astronomers did not realize that Mercury was a planet until 1543, when Copernicus created a heliocentric model of the solar system, in which the planets revolve around the sun.
7. The gravitational forces of the planet are 38% of the gravitational forces of the Earth. This means that Mercury is unable to retain the atmosphere it has, and what remains is blown away by the solar wind. However, these same solar winds attract gas particles and dust from micrometeorites to Mercury and form radioactive decay, which in some way forms an atmosphere.
8. Mercury has no moons or rings due to its low gravity and lack of atmosphere.
9. There was a theory that between the orbits of Mercury and the Sun there was an undiscovered planet Vulcan, but its presence was never proven.
10. Mercury's orbit is an ellipse, not a circle. It has the most eccentric orbit in the solar system.
11. Mercury has only the second highest temperature among the planets in the solar system. The first place is taken