To get an idea of just how big Mercury is, let's look at it in comparison to our planet.
Its diameter is 4879 km. This is approximately 38% of the diameter of our planet. In other words, we could put three Mercurys side by side and they would be just a tiny bit bigger than the Earth.
What is the surface area
The surface area is 75 million square kilometers, which is approximately 10% of the Earth's surface area.
If you could unfold Mercury, it would be almost twice the size of Asia (44 million square kilometers).
What about volume? The volume is 6.1 x 10 * 10 km3. That's a big number, but it's only 5.4% of the Earth's volume. In other words, we could fit 18 Mercury-sized objects inside the Earth.
Weight is 3.3 x 10 * 23 kg. Again, this is a lot, but in the ratio it is equal to only 5.5% of the mass of our planet.
Finally, let's look at the force of gravity on its surface. If you could stand on the surface of Mercury (in a good, heat-resistant space suit), you would feel 38% of the gravity you feel on Earth. In other words, if you weigh 100 kg, then Mercury is only 38 kg.
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A journey through the planetary population of the solar system should begin with the planet whose orbit is closest to the Sun - this is Mercury. However, the fact that the orbit of Mercury is closest to our star is not an argument for scientists. This has led to the fact that mankind has relatively little knowledge about this planet.
The history of the discovery of the planet
About Mercury, but then it was called "Naboo", was known to the Sumerians in the 14th century BC. e. Later, depending on the era, different astronomers called it differently, but the planet got its real name - Mercury, during the time of the Romans in honor of the god of trade, because of its rapid movement across the sky.
10 things you need to know about Mercury!
- Mercury is the first planet from the Sun.
- There are no seasons on Mercury. The tilt of the planet's axis is almost perpendicular to the plane of the planet's orbit around the Sun.
- The temperature on the surface of Mercury is not the highest, although the planet is located closest to the Sun. He lost first place to Venus.
- The first research vehicle to visit Mercury was Mariner 10. It conducted a series of demonstration flybys in 1974.
- A day on Mercury lasts 59 Earth days, and a year is only 88 days.
- On Mercury, the most dramatic temperature changes are observed, which reach 610 ° C. During the day, the temperature can reach 430 ° C, and at night -180 ° C.
- The force of gravity on the surface of the planet is only 38% of the Earth's. This means that on Mercury you could jump three times as high, and it would be easier to lift heavy objects.
- The first telescope observations of Mercury were made by Galileo Galilei in the early 17th century.
- Mercury has no natural satellites.
- The first official map of the surface of Mercury was published only in 2009, thanks to data obtained from the Mariner 10 and Messenger spacecraft.
Astronomical characteristics
The meaning of the name of the planet Mercury
According to tradition, the Romans named the heavenly bodies after one of their many gods. Mercury was no exception, and got its name in honor of the patron god of travelers and merchants. The choice for this name was not accidental, since Mercury moves faster than other planets in the sky, which is quite consistent with cunning ancient Roman merchants.
Physical characteristics of Mercury
Rings and satellites
No satellites revolve around the planet and there are no rings. Unfortunately in this regard, Mercury is not a very interesting space object.
Planet Features
The elliptical orbit of Mercury, the smallest planet in the solar system, causes it to approach the Sun by 47 million km and move away by 70 million km. If you had the opportunity to stand on the scorching surface of Mercury, then at the moment of the closest approach of the planet to the Sun, it would seem to you three times larger than on Earth.
The temperature on the surface of Mercury can reach 430 °C. Since the planet is not able to store the heat received from the Sun, due to the absence of an atmosphere, the night temperature on the surface can drop to -170 ° C.
Since Mercury is very close to the Sun, it is extremely difficult to observe it from Earth, except at twilight. Indirectly, Mercury can be observed indirectly, but only 13 times per century. More frequent observations of the planet closest to the Sun can be made directly on the solar disk. Such passages of the planet against the background of a star are called transits. This phenomenon can be observed twice a year, on May 8 and November 10.
Initially, astronomers assumed that the planet always faced one side of the Sun, but in 1965, thanks to radar observations, it was found that Mercury makes three revolutions around itself during the passage of two orbits. A year on Mercury is shorter than on Earth, and is equal to 88 Earth days. This is due to the high speed of movement in orbit, about 50 km / s, faster than any other planet. But one Mercury day is much longer than the Earth day and is equal to 58 Earth days.
Due to the absence of an atmosphere on Mercury, meteorites do not burn up when they fall, as happens on other planets that have atmospheres. As a result, the surface of the planet resembles that of the Moon, also covered with scars from the fall of meteoroids and comets. The landscape of the planet is quite diverse and can surprise both with incredibly smooth areas and cliffs and rocks, reaching up to several hundred kilometers in length and up to 1.6 kilometers in height, formed as a result of the planet's compression.
The "Plain of Heat" is the biggest feature of Mercury's surface. The diameter of this impact crater reaches 1550 (one third of the diameter of the planet) kilometers and is the largest impact structure in the solar system.
Over the last 1.5 billion years of its life, Mercury has shrunk in radius by about 1-2 kilometers. The outer crust of the planet has already strengthened enough to prevent magma from erupting to the surface, thus ending geological activity.
Mercury is the smallest planet in the solar system (the second after Pluto, but it is already recognized as a dwarf planet and does not participate in the ranking). Mercury is the second densest planet after Earth. Its large iron core has a radius of 1800 - 1900 kilometers, which is about 75% of the size of the planet. The outer shell of Mercury is comparable to the outer shell of the Earth (the so-called mantle) and is only 500 - 600 kilometers wide. Mercury, thanks to its iron core, has a magnetic field that, according to Mariner-10 measurements, is about 100 times smaller than Earth's, but scientists are unsure of its strength.
planetary atmosphere
The atmosphere on Mercury still exists and consists mainly of oxygen, but you won’t be able to breathe there. Due to its low density, the pressure on the planet's surface is only 10-15 bar, which is 5*10 11 times less than on Earth.
The gas envelope of the planet dissipated shortly after the formation of the planet 4.6 billion years ago. Astronomers suggest that it was simply "blown away" by the solar wind due to its proximity to the Sun.
The composition of the atmosphere is quite diverse and is presented in the table below.
Useful articles that will answer most of the interesting questions about Mercury.
deep sky objects
Mercury is one of the planets in our solar system. It is less discussed, not much is known about it, but despite this, scientists do not cease to closely monitor it. It is difficult to imagine how many mysteries this planet holds, but there are interesting facts that have become known relatively recently.
Close to the sun
Mercury is the closest planet to the Sun. The distance between these two objects is no more than 58 million kilometers. In fact, in the cosmic dimension, this distance is nothing.
The smallest
Of the eight planets in the solar system, Mercury is the smallest. In comparison with the Earth, the diameter of its equator is three times smaller. However, this does not prevent the “baby” from entering the top five planets that can be seen with the naked eye in the night sky.
high density
Mercury is rightfully one of the densest planets in the solar system. It ranks second in density, second only to our Earth in this characteristic.
hilly surface
Due to the compression and cooling of the iron core of Mercury, its surface became wrinkled. Interestingly, the scarps, as astronomers call them, only look like wrinkles in superficial photographs. In fact, their height exceeds hundreds of kilometers.
On Mercury, eruptions of specific geysers periodically occur. They emit hydrogen, and have practically nothing to do with the earthly phenomenon familiar to us.
Warm where the sun warms
Despite its close proximity to the Sun, Mercury is not the hottest planet. The temperature of its atmosphere does not exceed 430 degrees Celsius, but only one side heats up. On the opposite surface, turned away from the Sun, the temperature drops to −180°C. The reduced density of the atmosphere makes it impossible to keep warm or cold, so there are sharp temperature changes. Interestingly, Venus takes the lead in terms of high temperature.
littered with craters
Mercury often had to deal with various kinds of comets and asteroids that left their mark on the planet. The place of collision with space objects is called craters, and those that exceed 250 kilometers in diameter are called pools. The largest basin of the "solar neighbor" is the "Plain of Heat" (Caloris), its diameter reaches about 1550 kilometers - a third of the diameter of the planet. It is difficult to imagine the impact force that caused the creation of the pool.
Guests from Earth
In the entire history of mankind, Mercury was visited by only two terrestrial objects, one of which is still in orbit ("Messenger"). It was launched on August 3, 2004. The second object is the interplanetary station Mariner 10, sent in 1974 to study Mercury. She managed to circle the planet several times and transmit unique images to Earth.
No opener
It is still unknown who became the discoverer of Mercury. This planet is visible from Earth even without a telescope, which is probably why it was mentioned long before our era. One thing is known that the discovery happened precisely when a person became interested in the night sky and mysterious stars.
Atmosphere regeneration
Despite the strongest solar wind, the atmosphere on Mercury is still present. It is surprising that it is preserved under such influence of the Sun. Scientists explain this by the fact that the atmosphere of Mercury is able to regenerate, which is why it is kept on the planet.
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Of all the currently known planets in the solar system, 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 position 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. The preliminary orbital resonance of Mercury 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 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 get into 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.
So, what is the planet Mercury and what is so special about it that distinguishes it from other planets? Probably, first of all, it is worth listing the most obvious things that can be easily gleaned from various sources, but without which it will be difficult for a person to compose an overall picture.
At the moment (after Pluto was "demoted" to a dwarf planet), 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 makes a revolution around our star much faster than other planets. Apparently, it was the latter quality that served as the reason to name it in honor of the fastest messenger of the Gods named Mercury, an outstanding character from the legends and myths of 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 the "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 make their rotation around the Sun, and not around.
Mercury today
Nowadays, scientists know that due to the close proximity of Mercury to the Sun, the temperature on its surface can reach up to 450 degrees Celsius. But the absence 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 day and night 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 that, 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, mankind 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. At the same time, the vacuum in the atmosphere of this planet is much closer to the true vacuum, if compared with any other vacuum created on Earth using technical means.
There are two explanations for the absence of an atmosphere on Mercury. First, it 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 most 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 blow away the last remnants of what can be called an atmosphere.
However, no matter how poor the atmosphere on this planet is, it still exists. According to the NASA space agency, in terms of its chemical composition, it consists of 42% oxygen (O2), 29% sodium, 22% hydrogen (H2), 6% helium, 0.5% potassium. The remaining insignificant part is made up 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 surface of the planet. The lowest temperature can be around -180°C and the highest around 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 just 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, leaving unhindered into outer space.
Until 1974, the surface of Mercury remained largely a mystery. Observations of this cosmic body from the Earth were very difficult due to the proximity of the planet to the Sun. It was possible to consider Mercury only before dawn or immediately after sunset, but on Earth at this time the line of sight is significantly limited by too dense layers of the atmosphere of our planet.
But in 1974, after a magnificent three-time flyby of the surface of Mercury by the Mariner 10 spacecraft, the first sufficiently 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 the analysis of 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 "Kaloris" 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 as a result of the movement of lava flows through the planet in the past.
And, finally, the third feature is the rocks scattered over 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 active volcanic activity was once present in the historical past of the planet. However, the number and age of the craters, on the contrary, indicate that Mercury was geologically passive for a very long time.
But no less interesting is the third distinctive feature of the surface of Mercury. It turned out that the hills are formed by the activity of the planet's core, as a result of which the so-called "buckling" of the crust occurs. Such bulges on Earth are usually associated with the displacement of tectonic plates, while the loss of stability of the crust of Mercury occurs due to the contraction of its core, which is gradually compressed. The processes occurring with the core of the planet lead to the contraction of the planet itself. The latest 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: crust, mantle, and 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, reminiscent of the earth in their shape, indicates that, despite sufficient hardness, 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 in the past there was a collision of the planet with a huge planetesmial, which led to the loss of a significant mass of the mantle.
The core of Mercury has become the subject of many studies. It is believed to be 3,600 kilometers in diameter and has some unique properties. The most interesting property is its density. Given that the planetary diameter of Mercury is 4878 kilometers (it is smaller than the satellite of Titan, whose diameter is 5125 kilometers and the satellite of 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 tried to explain this feature of the planet's core, and has cast doubt on the fact that the core of Mercury is actually solid. By measuring the features of the rebound of radio waves from the surface of the planet, a group of planetary scientists came to the conclusion that the core of the planet is actually liquid and this explains a lot.
Orbit and rotation of Mercury
Mercury is much closer to the Sun than any other planet in our system and, accordingly, it takes the shortest time to complete its 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. Also, of all the planetary orbits, Mercury's orbit is the least circular.
This eccentricity, along with the absence of a significant atmosphere, explains why the surface of Mercury has the widest range of extreme temperatures in the solar system. Simply put, the surface of Mercury heats up much more when the planet is at perihelion than when it is at aphelion, since the difference in distance between these points is too great.
The orbit of Mercury itself is a perfect example of one of the leading processes in modern physics. This is a process called precession, which explains the shift in Mercury's orbit relative to the Sun over time.
Although Newtonian mechanics (i.e. classical physics) predicts the rates of this precession in great detail, the exact values have not been determined. This became a real problem for astronomers in the late nineteenth and early twentieth centuries. In order to explain the difference between theoretical interpretations and actual observations, many concepts have been drawn up. According to one theory, it has even been suggested that there is an unknown planet whose orbit is closer to the Sun than that of Mercury.
However, the most plausible explanation came 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 the spin-orbital resonance of Mercury (the number of revolutions in the orbit) was 1:1, but, in the end, it was proved that in fact it is 3:2. It is thanks to this resonance that a phenomenon is possible on the planet that is impossible on Earth. If the observer were on Mercury, he could see that the Sun rises to the highest point in the sky, and then "turns on" the reverse motion and descends in the same direction from which it rose.
- 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. at the Sumerians.
- A year on Mercury is 88 Earth days, but a Mercury day is 176 Earth days. Mercury is almost completely blocked by the Sun's tidal forces, but over time it makes a slow rotation of the planet around its axis.
- Mercury revolves so fast around the sun that some early civilizations believed that they were actually two different stars, one of which appears in the morning and the other in the evening.
- 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.
- 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 attribute it to the terrestrial planets.
- Astronomers did not realize that Mercury was a planet until 1543, when Copernicus created the heliocentric model of the solar system, according to which the planets revolve around the sun.
- The gravitational forces of the planet are 38% of the gravitational forces of the Earth. This means that Mercury is unable to hold on to the atmosphere it has, and what is left is blown away by the solar wind. However, all the same solar winds attract gas particles to Mercury, dust from micrometeorites and form radioactive decay, which in some way forms an atmosphere.
- Mercury has no moons or rings due to its low gravity and lack of an atmosphere.
- There was a theory that between the orbits of Mercury and the Sun there is the still undiscovered planet Vulcan, but its presence has never been proven.
- Mercury's orbit is an ellipse, not a circle. It has the most eccentric orbit in the solar system.
- Mercury is only the second hottest planet in the solar system. The first place is
