What can you say about the atmosphere of Mercury? The planet Mercury is the closest to the Sun. The atmosphere of Mercury: origin and current state

The surface of Mercury, in short, resembles the Moon. Vast plains and many craters indicate that geological activity on the planet ceased billions of years ago.

Surface character

The surface of Mercury (photo shown later in the article), taken by the Mariner 10 and Messenger probes, looked similar in appearance to the Moon. The planet is largely dotted with craters of various sizes. The smallest ones visible in the most detailed photographs of Mariner measure several hundred meters in diameter. The space between large craters is relatively flat and consists of plains. It is similar to the surface of the Moon, but takes up much more space. Similar areas surround Mercury's most prominent impact structure, the Caloris Planitia basin. Only half of it was illuminated when Mariner 10 encountered it, but it was fully discovered by Messenger during its first flyby of the planet in January 2008.

Craters

The most common landforms on the planet are craters. They largely cover the surface (photos below) at first glance similar to the Moon, but upon closer examination they reveal interesting differences.

Mercury's gravity is more than twice that of the Moon, partly due to the density of its huge core of iron and sulfur. The strong force of gravity tends to keep the material ejected from the crater close to the collision site. Compared to the Moon, it fell at a distance of only 65% ​​of the lunar distance. This may be one of the factors that contributed to the appearance of secondary craters on the planet, formed under the influence of ejected material, in contrast to the primary ones, which arose directly from a collision with an asteroid or comet. Higher gravity means that complex shapes and the structures characteristic of large craters—central peaks, steep slopes, and level bases—are observed in smaller craters on Mercury (minimum diameter of about 10 km) than on the Moon (about 19 km). Structures smaller than these sizes have simple bowl-like outlines. Mercury's craters are different from those on Mars, although the two planets have comparable gravity. Fresh craters on the first are, as a rule, deeper than comparable formations on the second. This may be a consequence of the low volatile content of Mercury's crust or higher impact velocities (since the object's speed is at solar orbit increases as you approach the Sun).

Craters larger than 100 km in diameter begin to approach the oval shape characteristic of such large formations. These structures - polycyclic basins - have dimensions of 300 km or more and are the result of the most powerful collisions. Several dozen of them were discovered on the photographed part of the planet. Messenger images and laser altimetry have made major contributions to understanding these residual scars from early asteroid bombardments on Mercury.

Plain of Heat

This impact structure extends over 1550 km. When it was initially discovered by Mariner 10, it was thought to be much smaller. The interior of the object consists of smooth plains covered with folded and broken concentric circles. The largest ridges extend several hundred kilometers in length, about 3 km in width and less than 300 meters in height. More than 200 fractures, comparable in size at the edges, emanate from the center of the plain; many of them are depressions bounded by grooves (grabens). Where grabens intersect with ridges, they tend to pass through them, indicating their later formation.

Surface types

The Zhary Plain is surrounded by two types of terrain - its edge and the relief formed by discarded rock. The edge is a ring of irregular mountain blocks, reaching 3 km in height, which are the most high mountains, found on a planet with relatively steep slopes towards the center. The second, much smaller ring is located 100-150 km from the first. Beyond the outer slopes is a zone of linear radial ridges and valleys, partially filled with plains, some of which are dotted with numerous mounds and hills several hundred meters high. The origin of the formations that make up the wide rings around the Zhara basin is controversial. Some plains on the Moon were formed largely by the interaction of ejecta with pre-existing surface topography, and this may also be true for Mercury. But the results of Messenger give reason to assume that a significant role in their formation was played by volcanic activity. Not only are there few craters there compared to the Zhara basin, indicating a protracted period of plain formation, but they have other features more clearly associated with volcanism than could be seen in the Mariner 10 images. Crucial evidence of volcanism came from Messenger images showing volcanic vents, many of which lie along the outer edge of the Zhara Plain.

Raditladi Crater

Caloris is one of the youngest large polycyclic plains, at least on the explored part of Mercury. It probably formed at the same time as the last giant structure on the Moon - about 3.9 billion years ago. Messenger images revealed another, much smaller impact crater with a visible inner ring that may have formed much later, called the Raditladi Basin.

Strange antipode

On the other side of the planet, exactly 180° opposite the Plain of Heat, is a patch of strangely distorted terrain. Scientists interpret this fact by talking about their simultaneous formation by focusing seismic waves from events that affected the antipodal surface of Mercury. The hilly and line-dotted terrain is a vast area of ​​uplands, which are hilly polygons 5-10 km wide and up to 1.5 km high. Pre-existing craters were transformed into hills and cracks by seismic processes, as a result of which this relief was formed. Some of them had a flat bottom, but then its shape changed, indicating their later filling.

Plains

A plain is the relatively flat or gently undulating surface of Mercury, Venus, Earth and Mars and is found throughout these planets. It represents the “canvas” on which the landscape developed. The plains are evidence of the process of destruction of rough terrain and the creation of smoothed space.

There are at least three methods of “grinding” that probably smoothed the surface of Mercury.

One way - increasing temperature - reduces the strength of the bark and its ability to hold high relief. Over millions of years, the mountains will “sink”, the bottom of the craters will rise and the surface of Mercury will level out.

The second method involves moving rocks towards lower areas of the area under the influence of gravity. Over time, rock accumulates in low-lying areas and fills higher levels as its volume increases. This is how lava flows from the bowels of the planet behave.

The third method is for rock fragments to fall onto the surface of Mercury from above, which ultimately leads to the leveling of rough terrain. Examples of this mechanism include rock emissions from cratering and volcanic ash.

Volcanic activity

Some evidence favoring the hypothesis of the influence of volcanic activity on the formation of many of the plains surrounding the Zhara basin has already been given. Other relatively young plains on Mercury, particularly visible in regions illuminated at low angles during Messenger's first flyby, show characteristics volcanism. For example, several old craters were filled to the brim with lava flows, similar to similar formations on the Moon and Mars. However, widespread plains on Mercury are more difficult to assess. Because they are older, it is clear that volcanoes and other volcanic features may have eroded or otherwise collapsed, making them difficult to explain. Understanding these old plains is important because they are likely responsible for the disappearance of most of the 10-30 km diameter craters compared to the Moon.

Scarps

The most important landforms of Mercury that provide insight into the planet's internal structure are the hundreds of jagged scarps. The length of these rocks varies from tens to more than thousands of kilometers, and their heights range from 100 m to 3 km. When viewed from above, their edges appear rounded or jagged. It is clear that this is the result of cracking, when part of the soil rose and lay on the surrounding area. On Earth, such structures are limited in volume and arise during local horizontal compression in earth's crust. But the entire explored surface of Mercury is covered with scarps, which means that the planet’s crust has shrunk in the past. From the number and geometry of scarps it follows that the planet has decreased in diameter by 3 km.

Moreover, the shrinkage must have continued until relatively recently. geological history time, as some scarps have altered the shape of well-preserved (and therefore relatively young) impact craters. The slowing down of the planet's initially high rotation rate by tidal forces produced compression in Mercury's equatorial latitudes. The globally distributed scars, however, suggest another explanation: late cooling of the mantle, perhaps combined with the solidification of part of the once completely molten core, led to compression of the core and deformation of the cold crust. The reduction in the size of Mercury as its mantle cooled should have led to more longitudinal structures than can be seen, which indicates the incompleteness of the compression process.

The surface of Mercury: what is it made of?

Scientists have tried to figure out the composition of the planet by studying sunlight reflected from different parts of it. One of the differences between Mercury and the Moon, besides the former being slightly darker, is that it has a smaller spectrum of surface brightnesses. For example, the seas of the Earth's satellite are smooth spaces visible to the naked eye as large dark spots- much darker than the cratered highlands, and the plains of Mercury are only slightly darker. The color differences on the planet are less pronounced, although Messenger images taken using a set of color filters showed small, very colorful areas associated with volcanic vents. These features, as well as the relatively featureless visible and near-infrared spectrum of the reflected sunlight, suggest that the surface of Mercury consists of silicate minerals, not rich in iron and titanium, of a darker color, compared to the lunar seas. In particular, the planet's rocks may be low in iron oxides (FeO), leading to speculation that it was formed under much more reducing conditions (i.e., lack of oxygen) than other members of the terrestrial group.

Problems of remote research

It is very difficult to determine the planet's composition by remotely sensing sunlight and the thermal spectrum that Mercury's surface reflects. The planet is heating up greatly, which changes the optical properties of mineral particles and complicates direct interpretation. However, Messenger was equipped with several instruments not present on Mariner 10 that measured chemical and mineral composition directly. These instruments required a long observation period while the ship remained near Mercury, so concrete results after the first three short flights there were none. It was only during the Messenger orbital mission that sufficient new information emerged about the composition of the planet's surface.

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 with the garbage that the planet encounters on its way. Without these replenishment sources, it would be lost relatively quickly 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, spaceship NASA MESSENGER 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 to the surface, the magnetic field helps contain solar winds around the planet, just 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.

This article is a message or report about the planet Mercury, which outlines characteristic of this planet: parameters, description of the atmosphere, surface, orbit, as well as interesting facts.

The planet Mercury, named after the Roman god of trade, who also acted as the messenger of the gods, is closest to the center of all others solar system. This planet, located at a distance (on average) of 58 million km from the Sun, is very hot.

Parameters and description

Maximum distance from the Sun 70 million km
Minimum distance from the Sun 46 million km
Equator diameter 4878 km
Average surface temperature 350º C
Maximum temperature 430º C
Minimum temperature-170º C
Time to revolve around the Sun 88 earth days
Duration sunny days 176 earth days

On both sides of Mercury there are areas near the equator that are illuminated by the Sun most of the time. These two regions are called Mercury's "heat poles." During the Mercury day, the temperature changes very significantly. During the day, the surface of the planet warms up to an average of 350º C, sometimes up to 430º C. At this temperature, tin and lead melt. At night, the surface layers cool down to -170º C.

The main reason for such sharp temperature fluctuations is that Mercury, unlike Earth, is practically devoid of an atmosphere that absorbs heat during the day and does not allow the planet to cool down at night.

For a long time, astronomers believed that Mercury had no atmosphere at all, but now it is known that this planet still has a gaseous envelope, albeit an extremely rarefied one. For the most part it consists of sodium and helium with small amounts of hydrogen and oxygen (see Figure 1).

Rice. 1. Atmosphere of Mercury

Due to high temperature and low pressure Liquid water cannot exist on Mercury. However, as on Earth, water here is found in the form of ice at the poles. In some polar regions of the planet, where the Sun never looks, the temperature can constantly be around -148º C.

Thus, organic life impossible on Mercury.

Surface of the planet

These cataclysms apparently greatly heated Mercury, and when the meteorite bombardment ended, the planet began to cool and shrink. The compression led to the appearance of folds and long winding cliffs on the surface, called scarps. In some places their height can reach 3 km.

Like Earth, Mercury's relatively thin crust covers a thick layer of mantle surrounding a large, heavy iron-containing core. The average density of Mercury is extremely high. This suggests that the planet's core, relative to the rest of it, is very large and heavy. Astronomers say that Mercury's core makes up about 42% of its volume, while Earth's core makes up only 17%.

Elliptical orbit

Mercury orbits the Sun in 88 Earth days, faster than any other planet in the Solar System. Like the other planets, Mercury revolves around the Sun not in a circular orbit, but in an elongated or elliptical one.

Since the Sun is not in the center of this orbit, the distance between it and Mercury at different points varies greatly. The point at which Mercury is closest to the Sun is called perihelion, and the point at which Mercury is farthest from the Sun is aphelion.

Since the plane of Mercury's orbit is noticeably inclined relative to the Earth's orbit, it rarely, no more than a dozen times a century, passes between our planet and the Sun.

Mercury rotates not only around the Sun, but also around its own axis. This happens extremely slowly - one day on Mercury lasts 176 Earth days. As Mercury approaches perihelion, something very unusual happens. Since the planet’s motion accelerates as it approaches the Sun, the speed of Mercury’s movement along its orbit in a given segment exceeds the speed of the planet’s rotation around its axis. If you were on Mercury at such a time, you would see how the Sun, rising in the east, would cross the sky and set in the west, then reappear above the horizon, move across the sky in the opposite direction for a couple of earthly days, and then again it's gone.

Mercury is best seen at aphelion, when it is farthest from the Sun. This happens about 3 times a year.

Most of the information we have about Mercury has been obtained through radar and space probes. In addition, the Mariner 10 spacecraft, launched by the United States in the mid-1970s, repeatedly approached Mercury, transmitting images of its surface to Earth.

On August 3, 2004, the Messenger probe was launched from Cape Canaveral, which is still operating in orbit of the smallest planet in the solar system.

Some interesting facts

• Despite its maximum proximity to the Sun, Mercury is not the hottest planet in the solar system, giving way to Venus.

• Mercury has no satellites.

Mercury- the planet closest to the Sun ( general information about Mercury and other planets you will find in Appendix 1) - the average distance from the Sun is 57,909,176 km. However, the distance from the Sun to Mercury can vary from 46.08 to 68.86 million km. The distance of Mercury from Earth is from 82 to 217 million km. Mercury's axis is almost perpendicular to the plane of its orbit.

Due to the slight inclination of Mercury's rotation axis to the plane of its orbit, there are no noticeable seasonal changes on this planet. Mercury has no satellites.

Mercury is a small planet. Its mass is a twentieth of the mass of the Earth, and its radius is 2.5 times less than that of the Earth.

Scientists believe that in the center of the planet there is a large iron core - it accounts for 80% of the planet's mass, and on top is a mantle of rocks.

For observations from Earth, Mercury is a difficult object, since it must always be observed against the background of evening or morning dawn low above the horizon, and in addition, at this time the observer sees only half of its disk illuminated.

The first to explore Mercury was the American space probe Mariner 10, which in 1974-1975. flew past the planet three times. The maximum approach of this space probe to Mercury was 320 km.

The surface of the planet looks like a wrinkled apple peel, it is riddled with cracks, depressions, mountain ranges, the highest of which reach 2-4 km, sheer scarps 2-3 km high and hundreds of kilometers long. In a number of areas of the planet, valleys and craterless plains are visible on the surface. The average soil density is 5.43 g/cm3.

On the studied hemisphere of Mercury there is only one flat place - the Plain of Heat. It is believed that this is solidified lava that poured out from the depths after a collision with a giant asteroid about 4 billion years ago.

The atmosphere of Mercury has an extremely low density. It consists of hydrogen, helium, oxygen, calcium vapor, sodium and potassium (Fig. 1). The planet probably receives hydrogen and helium from the Sun, and metals evaporate from its surface. This thin shell can only be called an “atmosphere” with a big stretch. The pressure at the surface of the planet is 500 billion times less than at the surface of the Earth (this is less than in modern vacuum installations on Earth).

General characteristics of the planet Mercury

The maximum surface temperature of Mercury recorded by sensors is +410 °C. The average temperature of the night hemisphere is -162 °C, and the daytime hemisphere is +347 °C (this is enough to melt lead or tin). Temperature differences due to the change of seasons caused by the elongation of the orbit reach 100 °C on the day side. At a depth of 1 m, the temperature is constant and equal to +75 ° C, because porous soil conducts heat poorly.

Organic life on Mercury is excluded.

Rice. 1. Composition of Mercury's atmosphere

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.

At the moment (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 her in honor of the fastest-footed messenger of the Gods named Mercury, an extraordinary character from legends and myths Ancient Rome with 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.

Mercury is slightly larger in size than the Moon, but much heavier than ours. 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 influence solar winds, which demolish the last remnants of what can be called the atmosphere.

However, no matter how scarce the atmosphere on this planet is, it still exists. According to the space agency NASA, in its own way chemical composition it 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 rarefaction of the atmosphere is due to the presence of extreme temperatures on the surface of the planet. The most low temperature can be on the order of -180 °C, and the highest is 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 lack of a significant atmosphere prevents the planet from holding solar radiation and the 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 entire surface of the planet. 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. These smooth surface areas are believed to have been 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 one is no less interesting. distinguishing feature surface of Mercury. 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 approximate thickness of Mercury's mantle is about 600 kilometers, which suggests 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 much 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 modern physics. It's about 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 the Sun rising to its very high 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 planet's gravitational forces account for 38% of gravitational forces 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