Almost every planet in our solar system has a satellite. Some of them have dozens, for example, Jupiter has 67 of them. Does Mercury have satellites? As strange as it sounds, he doesn't have them.

Moons in the solar system are not uncommon. Even the smallest planet Pluto has an accompanying one, but why then does Mercury have no satellites?

Satellites

Our Moon has been accompanying the Earth for over a million years. According to scientists, it appeared after some space body, the size of Mars, crashed into the planet. Earth's gravity kept the debris in their orbit. Gradually, all the fragments formed a single object that we observe every night. Thus, the Earth had a Moon, accompanying it for many years.

According to astronomers' assumptions, Mercury had satellites, but once upon a time. But they either fell under the influence of the sun's gravity, or fell to the surface of the planet.

Mars has satellites - there are two of them: Phobos and Deimos. These are ordinary asteroids that are not able to overcome the gravity of the planet. The presence of two moons of the red planet is due to the close location of the asteroid belt. But next to Mercury there is no such cluster of meteorites, and very few of them fly past it.

Pluto also has satellites - these are, in particular, Nikta and Hydra, large ice blocks that were close to this planet and could not cope with gravity. If suddenly these objects were next to the Sun, then they would turn into comets and cease to exist.

Mercury has no satellites, and they are not expected to appear in the near future.

Historical reference

In the seventies, scientists suggested that Mercury has a satellite, the name of which they did not have time to come up with, since this opinion was erroneous. This conclusion was made after the outgoing ultraviolet radiation was detected thanks to the Mariner-10 equipment. Some scientists have suggested that such large doses of radiation can only come from the satellite of Mercury. Later it turned out that the reason for this was the effect of a distant star, and all assumptions about the presence of accompanying bodies turned out to be false.

First planet

The first planet Solar system is Mercury. It is an atmospheric world with many craters. Until the moment when the Messenger device flew to the planet, little was known about it. Now astronomers know a lot about her. For many years, Mercury has been accompanied by only one satellite, and even that one of terrestrial origin.

There is ice on the first celestial body in the solar system. He was found in craters where the sun's rays do not fall. Organic matter was also discovered, which is necessary for the construction of all living things. Such discoveries suggested that there was once life here. Sulfur and many other elements found on Earth have been found on the planet's surface. Scientists are still puzzling over the discovery of large reserves of sulfur, because no other planet has it in such quantities.

Artificial satellite

In 2011, a spacecraft entered orbit, which began to accompany the planet. Now we can safely answer the question of how many satellites Mercury has - one.

Thanks to the new accompaniment, astronomers managed to collect a lot of information about the planet. They know what is the angle of inclination of the axes, the period of rotation, the size of the planet. The device sent pictures of the planet's surface taken from space. The satellite was able to take photographs of the northern polar region, including the giant depression, the southern region, thereby closing all the gaps in information about the planet.

For the first time, scientists managed to see the structure of the planet, to examine in detail its relief from a very close distance.

Flying around the planet

The satellite of Mercury "Messenger" is constantly exposed to gravity from the Sun. As with vehicles flying around the Earth, the trajectory of the flight of the machine gradually changes. In particular, the minimum flight altitude is trying to go up, and the maximum is reduced. Due to such surges, the operating conditions of the equipment deteriorate. In order to somehow correct the research processes, a systematic analysis of the flight is periodically carried out, the trajectory is calculated. According to the plan, the restructuring of the apparatus will be carried out once per Mercurian year or once every 88 Earth days. The apocenter will rise three hundred kilometers with the first orbit, and with the second, it will descend to two hundred kilometers.

The main task of "Messenger" is to make as many images of the planet as possible from different areas. And astronomers received a huge number of photos, each of which is unique.

Natural satellites

As mentioned several times above, Mercury has no natural satellites. For them to arise, it is necessary either to fall on the planet of a huge number of asteroids, which would bounce off it and begin to fly in orbit, or to attract comets to itself, holding them by gravity. Presumably, according to the second scenario, an escort appeared on Mars and some gas planets.

According to many scientists, Mercury cannot be accompanied by its low gravitational force: it is not able to keep cosmic bodies in orbit. In addition, if a large asteroid entered the zone where the object could linger, then it would definitely fall under the influence of the Sun and simply dissolve.

Trying to find the photos and names of the satellites of Mercury, you can only find information about the artificial accompaniment of the planet, which was developed on Earth. This is how Mercury and Venus have to while away their lives in splendid isolation, flying around the Sun without being accompanied.

Comparatively small cosmic bodies that revolve around larger host planets are called natural satellites. In part, a whole science is devoted to them - planetology.

In the 70s, astronomers assumed that Mercury had several celestial bodies depending on it, since they caught ultraviolet radiation around it. Later it turned out that the light belonged to a distant star.

Modern equipment allows for a more detailed study of the planet closest to the Sun. Today, all planetary scientists in unison insist that it has no satellites.

Satellites of the planet Venus

Venus is called Earth-like because they have the same composition. But if we talk about natural space objects, then the planet named after the goddess of love is close to Mercury. These two planets of the solar system are unique in that they are completely alone.

Astrologers believe that previously Venus could have seen such, but to date, none have been found.

How many natural satellites does the Earth have?

Our native Earth has many satellites, but only one natural one, which every person knows about from infancy - this is the Moon.

The size of the Moon exceeds a quarter of the Earth's diameter and is 3475 km. She is the only celestial body with such large dimensions relative to the "owner".

Surprisingly, its mass is small at the same time - 7.35 × 10²² kg, which indicates a low density. Multiple craters on the surface are visible from Earth even without any special devices.

What satellites does Mars have?

Mars is a fairly small planet, sometimes called red because of its scarlet hue. It is given by iron oxide, which is part of its composition. Today Mars boasts two natural celestial objects.

Both satellites, Deimos and Phobos, were discovered by Asaf Hall in 1877. They are the smallest and darkest objects in our comic system.

Deimos translates as the ancient Greek god who sows panic and horror. Based on observations, it is gradually moving away from Mars. Phobos, bearing the name of the god who brings fear and chaos, is the only satellite that is so close to the "owner" (at a distance of 6000 km).

The surfaces of Phobos and Deimos are abundantly covered with craters, dust and various loose rocks.

Moons of Jupiter

Today, the giant Jupiter has 67 satellites - more than other planets. The largest of them are considered the achievement of Galileo Galilei, since they were discovered by him in 1610.

Among the celestial bodies orbiting Jupiter, it is worth noting:

• Adrasteus, with a diameter of 250 × 147 × 129 km and a mass of ~ 3.7 × 1016 kg;
• Metis - dimensions 60 × 40 × 35 km, weight ~ 2 × 1015 kg;
• Thebes, which has a scale of 116 × 99 × 85 and a mass of ~ 4.4 × 1017 kg;
• Amalthea - 250 × 148 × 127 km, 2 1018 kg;
• Io with a weight of 9 1022 kg at 3660 × 3639 × 3630 km;
• Ganymede, which with a mass of 1.5 × 1023 kg had a diameter of 5263 km;
• Europe, occupying 3120 km and weighing 5 · 1022 kg;
• Callisto, with a diameter of 4820 km and having a mass of 1 · 1023 kg.

The first satellites were discovered in 1610, some from the 70s to the 90s, then in 2000, 2002, 2003. The last of them were discovered in 2012.

Saturn and its moons

Found 62 satellites, of which 53 have names. Most of them are composed of ice and rock, with a reflective feature.

The largest space objects of Saturn:

How many satellites does Uranus have?

At the moment, Uranus has 27 natural celestial bodies. They are named after the characters famous works by Alexander Pope and William Shakespeare.

Names and list by quantity with description:

Moons of Neptune

The planet, whose name is consonant with the name of the great god of the seas, was discovered in 1846. She was the first to be found using mathematical calculations, and not thanks to observations. Gradually, new satellites were discovered at her, until they counted 14.

List

The moons of Neptune are named after nymphs and various sea deities from Greek mythology.

The beautiful Nereid was discovered in 1949 by Gerard Kuiper. Proteus is a non-spherical space body and is being studied in detail by planetary scientists.

Giant Triton is the iciest object in the solar system with a temperature of -240 ° C, and also the only satellite orbiting itself in the opposite direction to the rotation of the "host".

Almost all satellites of Neptune have craters on the surface, volcanoes - both fiery and ice. They spew out from their bowels a mixture of methane, dust, liquid nitrogen and other substances. Therefore, a person cannot be on them without special protection.

What are the "satellites of the planets" and how many are there in the solar system?

Satellites are cosmic bodies that are smaller in size than the "host" planets and revolve in their orbits. The question of the origin of satellites is still open and is one of the key issues in modern planetary science.

Today, 179 natural space objects are known, which are distributed as follows:

• Venus and Mercury - 0;
• Earth - 1;
• Mars - 2;
• Pluto - 5;
• Neptune - 14;
• Uranus - 27;
• Saturn - 63;
• Jupiter - 67.

Technologies are improving every year, finding more celestial bodies. Perhaps new satellites will be discovered soon. We just have to wait, constantly checking the news.

The largest satellite in the solar system

The largest in our solar system is considered to be Ganymede - the satellite of the giant Jupiter. Its diameter, according to scientists, is 5263 km. Next in size is Titan with a size of 5150 km - the "moon" of Saturn. The three leaders are closed by Callisto - Ganymede's "neighbor", with whom they share one "master". Its scale is 4800 km.

Why do planets need satellites?

Planetary scientists at all times asked the question "Why do we need satellites?" or "What impact do they have on the planets?" Based on observations and calculations, some conclusions can be drawn.

Natural satellites play an important role for "hosts". They create a certain climate on the planet. It is no less important that they serve as protection against asteroids, comets, and other dangerous celestial bodies.

Despite such a significant impact, satellites are still not mandatory for the planet. Even without their presence, life can form and be maintained on it. This conclusion was reached by American scientist Jack Lissauer from the NASA Space Science Center.

The solar system was formed about 4.6 billion years ago. The group of planets, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, together with the Sun make up the solar system.

The sun

The sun - the central body of the solar system - is a star, a huge sphere of gas, in the center of which nuclear reactions take place. The bulk of the mass of the solar system is concentrated in the sun - 99.8%. That is why the Sun holds by gravity all objects of the solar system, the size of which is not less than sixty billion kilometers. Samygin S.I. Concepts of modern science - Rostov-on-Don, Phoenix, 2008.

Four small planets revolve very close to the Sun, consisting mainly of rocks and metals - Mercury, Venus, Earth and Mars. These planets are called terrestrial planets.

Between the terrestrial planets and the giant planets is the asteroid belt Sagan K.E. Cosmos - M., 2000 .. A little further there are four large planets, consisting mainly of hydrogen and helium. The giant planets do not have a solid surface, but they have an extremely powerful atmosphere. Jupiter is the largest of them all. This is followed by Saturn, Uranus and Neptune. All giant planets have a large number of satellites, as well as rings.

The most recent planet in the solar system is Pluto, which in its physical properties is closer to the satellites of the giant planets. The so-called Kuiper belt, the second asteroid belt, is open beyond Pluto's orbit.

Mercury, the closest planet to the Sun in the solar system, has long been a complete mystery to astronomers. The period of its rotation around the axis was not accurately measured. Due to the lack of satellites, the mass was not known exactly. The proximity to the sun made it difficult to make observations of the surface.

Mercury

Mercury is one of the brightest objects in the sky. In terms of brightness, it is second only to the Sun, Moon, Venus, Mars, Jupiter and the star Sirius. In accordance with 3 Kepler's law, it has the smallest period of revolution around the Sun (88 Earth days). And the highest average speed of movement in orbit (48 km / s) V.R. Concepts of modern natural science - M., 2003 ..

The mass of Mercury is equal to the mass of the Earth. Pluto is the only planet with less mass. In terms of diameter (4880 km, less than half the earth's), Mercury is also in the penultimate place. But its density (5.5 g / cm3) is approximately equal to the density of the Earth. However, being much smaller than Earth, Mercury experienced slight compression under the influence of internal forces. Thus, according to calculations, the density of the planet before compression is 5.3 g / cm3 (for the Earth, this value is 4.5 g / cm3). Such a large uncompressed density, surpassing the density of any other planet or satellite, indicates that internal structure planets are different from the structure of the Earth or the Moon Isaac A. Earth and space. From reality to hypothesis - M., 1999 ..

The large value of the uncompressed density of Mercury should be due to the presence of a large amount of metals. According to the most plausible theory, in the bowels of the planet there should be a core consisting of iron and nickel, the mass of which should be about 60% of the total mass. And the rest of the planet should be made up mostly of silicates. The core diameter is 3500 km. Thus, it lies about 700 km from the surface. Simplistically, you can imagine Mercury in the form of a metal ball the size of the moon, covered with a rocky 700 kilometer crust.

One of the unexpected discoveries made by the American space mission "Mariner 10" was the discovery magnetic field... Although it is approximately 1% of Earth's, it is just as significant for the planet. This discovery was unexpected due to the fact that it was previously believed that inner part the planet has a solid state, and, therefore, the magnetic field could not form. It is difficult to understand how such a small planet was able to retain enough heat to keep its core liquid. The most probable assumption is that in the core of the planet there is a significant part of iron and sulfur compounds, which slow down the cooling of the planet and due to this, at least the gray-iron part of the core is in a liquid state. Sagan K.E. Space - M., 2000

The first data characterizing the planet at close range was obtained in March 1974 thanks to the spacecraft launched as part of the American space mission Mariner 10, which approached a distance of 9500 km and photographed the surface at a resolution of 150 m.

Although the surface temperature of Mercury has already been determined on Earth, more accurate data have been obtained from close measurements. The temperature on the daytime side of the surface reaches 700 K, approximately the melting point of lead. However, after sunset, the temperature quickly drops to about 150 K, after which it cools down more slowly to 100 K. Thus, the temperature difference on Mercury is about 600 K, greater than on any other planet A.P. Sadokhin. Concepts of modern natural science - M., Unity, 2006 ..

Mercury strongly resembles the Moon in appearance. It is covered with thousands of craters, the largest of which reach 1300 km in diameter. Also on the surface there are steep slopes that can exceed a kilometer in height and hundreds of kilometers in length, ridges and valleys. Some of the largest craters have rays like the craters of Tycho and Copernicus on the Moon and many of them have central peaks V.L. Gor'kov, Yu.F. Avdeev. Space alphabet. Book about space - M., 1984 ..

Most of the relief objects on the planet's surface were named after famous artists, composers and representatives of other professions who have contributed to the development of culture. The largest craters are named Bach, Shakespeare, Tolstoy, Mozart, Goethe.

In 1992, astronomers discovered areas with high level reflections of radio waves, in their properties similar to the properties of reflection at the poles on Earth and on Mars. It turned out that these areas contain ice in craters covered in shadow. Although the existence of such low temperatures was not unexpected, the mystery was the origin of this ice on the planet, the rest of which is affected high temperatures and completely dry.

Mercury's hallmarks — the long slopes that sometimes criss-cross craters — are evidence of compression. Obviously, the planet was shrinking, and cracks were running along the surface. And this process took place after most of the craters were formed. If the standard crater chronology is correct for Mercury, then this contraction must have occurred during the first 500 million years of Mercury's history.

Brown-gray Mercury is the little-studied first planet in our solar system. After Object 9 Pluto was demoted from the title of "planet", the closest neighbor of the Sun became the smallest planet. Object number 1 is endowed with many secrets and unsolved facts. Scientists are still worried about whether there are satellites of Mercury in outer space.

Artificial satellite

The jumping planet, as the ancient inhabitants of the Earth called Mercury, has been of interest to astronomers since the time dating back to the name "BC". Ancient Egyptians and Romans mentioned the mysterious "morning star", while the Sumerians, who saw Mercury in the firmament, called it "Mul apin".

After modern technology has gone ahead by leaps and bounds, Mercury has become one of the main objects of space exploration and our solar system. Looking at the planet through telescopes, astronomers have long cherished hopes to study the first neighbor of the star and understand what is happening on it.

For the first time it was possible to send a probe towards the brown-gray object No. 1 in 1973. The American research company NASA sent the probe "Mariner-10" to conquer the near-Mercurian expanses. The task of the apparatus was to fly over a small planet and photograph its surface. Since no satellites were previously seen near Mercury, scientists hoped that Mariner 10 would be able to reveal, possibly, objects hidden in the planet's shadow.

The hope that the planet still has a satellite or some object in orbit was given to astronomers by ultraviolet radiation, the activity of which was observed before the passage of the probe of the space boundaries of planet No. 1. Arriving at the horizons of Mercury, "Mariner-10" in March 1974, did not find a mysterious stellar object that excited the terrestrial equipment of the flying probe, and the ultraviolet burst scattered as if it had never existed.

Once again, the hope that the satellites of Mercury did exist a few days later, when the NASA probe again caught an ultraviolet burst and recorded an object moving away from the planet at a speed of 4 meters per second. Further analysis of the data showed that Mariner 10 recorded information from a completely different distant object located in a neighboring galaxy.

The first artificial satellite of planet # 1 was destined to become the new NASA spacecraft. The modern conqueror of the stellar expanses was named "Messenger". Having successfully started on August 3, 2004 from Cape Canaveral, the "spy" of earthlings reached a brown-gray body in early 2008. The "Messenger" device transmitted the first images to the mission control center, and scientists once again realized that the natural satellites of Mercury does not exist.

In 2011, a ground vehicle belonging to the American aerospace company made several maneuvers in the object's weak atmosphere and forever became its first man-made escort of Mercury. But the list of artificial objects near planet # 1 does not end there.

In October this year, several spacecraft belonging to the European Space Agency and united in the BepiColombo mission left the Earth's limits. Robotic explorers of Mercury belong to several states, and astronomy plans include a complete study of the first planet from the Sun. It is assumed that Russia will also take part in the study of the smallest planet in our system after 2031; other passage scientific works and their details have not yet been determined.

Natural satellites

After terrestrial experts began to actively monitor the "vital activity" of Mercury, the discovery of the alleged satellite became possible, and scientists pin great hopes on this. At this stage of space exploration, the characteristics of planet # 1 indicate that it is difficult for an object to form its own neighbor.

There are several reasons why Mercury does not have natural companions rotating in its orbit. First, the object's gravity relative to a nearby scorching star is small, and it cannot attract and detain even small asteroids. Secondly, strong solar winds, which constantly attack small planets, interfere in the "capture" of the orbital captive.

Perhaps in the distant past, when our universe was still forming, Mercury had natural satellites. Millennia passed, and the impact of the fiery neighbor of the Sun disrupted the idyll of cosmic interaction, swallowing up hypothetical Mercurian moons.
In addition to the question of the number of satellites, the second most popular question is how many rings the planet has. Modern data obtained from the device "Messenger" indicate that Mercury has not only satellites, but also rings.

The formation of neither one nor the other object of planetary significance in nature at this moment is impossible. This is due to the fact that body # 1 is not located near the asteroid belt, like the red neighbor in the solar system Mars. Gravitational indices do not attract large cosmic bodies and Trojan asteroids into the orbit of the smallest planet.

Speaking simple language, the planet simply does not have the material to create rings or a companion to accompany it in the cold stellar space. The only rings visible with the given equipment settings are the planet's magnetic field rings.

Locating a prospective satellite

There is a debate among astronomers regarding the moons of planet # 1. Some space scientists are sure that objects invisible through telescopes simply must exist. They argue that if you find a solution to a school problem in physics with the condition "determine the first cosmic velocity for a satellite of Mercury flying somewhere in the bowels of the solar system", you will get a reasonable answer to a centuries-old question. Knowing the mass and radius of object No. 1, using formulas it is easy to determine that the required value is equal to 2999.5 meters per second.

The condition of another popular problem, which sounds like "calculate the orbital period of the satellite of Mercury, which is not far from the planet," will help the curious to determine a tangible indicator of astronomical scale. Using the planetary values ​​of the object's mass and radius, it can be calculated that the orbital period is 85 minutes. For several years now, such tasks have been popular among students taking the EGE.

Double star

For a long time, astronomers of the Earth were haunted by the question of whose ultraviolet radiation was discovered in the early 70s. last century, the American apparatus "Mariner-10". After analyzing the available information, it became clear that the probe had caught "galactic greetings" from the double star 31, which is located in the constellation Chalice. The orbital period of the stellar "minx" around its own star is almost 3 days.

As scientists did not try to determine who owns the second burst of cosmic radiation, tracked by "Mariner-10", their attempts were unsuccessful. The question remained unanswered, and there is hope that in subsequent flights to the orbit of Mercury, knowledge about this planet will expand and be replenished with new facts.

Mercury is the first body of our solar system, the flight to which is one of the most difficult. This is explained by the close proximity of the object to our star. But astronomers do not give up hope that the planned missions to the smallest planet in the future will be crowned with success and bring new knowledge about space.