The period of pluto's revolution around the sun. The planet Pluto is a tiny little thing lost in the outskirts of the solar system

Pluto is one of the least studied objects in the solar system. Due to its great distance from Earth, it is difficult to observe with telescopes. Its appearance is more reminiscent of a small star than a planet. But until 2006, it was he who was considered the ninth planet of the solar system known to us. Why was Pluto excluded from the list of planets, what led to this? Let's look at everything in order.

Unknown to science "Planet X"

At the end of the 19th century, astronomers suggested that there must be another planet in our solar system. The assumptions were based on scientific data. The fact is that, observing Uranus, scientists discovered a strong influence on its orbit of foreign bodies. So, after some time Neptune was discovered, but the influence was much stronger, and the search for another planet began. It was called "Planet X". The search continued until 1930 and was successful - Pluto was discovered.

Pluto's movement was noticed on photographic plates taken over a two-week period. Observations and confirmation of the existence of an object beyond the known boundaries of the galaxy of another planet took more than a year. Clyde Tombaugh, a young astronomer at the Lowell Observatory that initiated the research, reported the discovery to the world in March 1930. Thus, a ninth planet appeared in our solar system for 76 years. Why was Pluto excluded from the solar system? What was wrong with this mysterious planet?

New discoveries

At one time, Pluto, classified as a planet, was considered the last of the objects in the solar system. According to preliminary data, its mass was considered equal to the mass of our Earth. But the development of astronomy constantly changed this indicator. Today, Pluto's mass is less than 0.24% and its diameter is less than 2,400 km. These indicators were one of the reasons why Pluto was excluded from the list of planets. It is more suitable for a dwarf than for a full-fledged planet in the solar system.

It also has many of its own features that are not typical for ordinary planets in the solar system. The orbit, its small satellites and atmosphere are unique in themselves.

Unusual orbit

The orbits familiar to the eight planets of the Solar System are almost circular, with a slight inclination along the ecliptic. But Pluto's orbit is a highly elongated ellipse and has an inclination angle of more than 17 degrees. If you imagine, eight planets will rotate evenly around the Sun, and Pluto will cross the orbit of Neptune due to its angle of inclination.

Due to this orbit, it completes a revolution around the Sun in 248 Earth years. And the temperature on the planet does not rise above minus 240 degrees. Interestingly, Pluto rotates in the opposite direction from our Earth, like Venus and Uranus. This unusual orbit for a planet was another reason why Pluto was excluded from the list of planets.

Satellites

Today there are five known: Charon, Nyx, Hydra, Kerberos and Styx. All of them, except Charon, are very small, and their orbits are too close to the planet. This is another difference from the officially recognized planets.

In addition, Charon, discovered in 1978, is half the size of Pluto itself. But it's too big for a satellite. Interestingly, the center of gravity is outside of Pluto, and therefore it seems to sway from side to side. For these reasons, some scientists consider this object to be a double planet. And this also serves as an answer to the question of why Pluto was excluded from the list of planets.

Atmosphere

It is very difficult to study an object located at an almost inaccessible distance. Pluto is believed to be composed of rock and ice. The atmosphere on it was discovered in 1985. It consists mainly of nitrogen, methane and carbon monoxide. Its presence was determined by studying the planet when it covered the star. Objects without an atmosphere cover the stars abruptly, while those with an atmosphere cover them gradually.

Due to the very low temperature and elliptical orbit, melting ice produces an anti-greenhouse effect, causing the planet's temperature to drop even further. After research conducted in 2015, scientists came to the conclusion that atmospheric pressure depends on the planet’s approach to the Sun.

Newest technologies

The creation of new powerful telescopes marked the beginning of further discoveries beyond the known planets. So, over time, those located within the orbit of Pluto were discovered. In the middle of the last century, this ring was called the Kuiper belt. Today, hundreds of bodies are known with a diameter of at least 100 km and a composition similar to Pluto. The found belt turned out to be the main reason why Pluto was excluded from the planets.

The creation of the Hubble Space Telescope made it possible to study outer space, and especially distant galactic objects, in more detail. As a result, an object was discovered, called Eris, which turned out to be further than Pluto, and over time, two more celestial bodies that were similar in diameter and mass to it.

The New Horizons spacecraft, sent to explore Pluto in 2006, confirmed many scientific data. Scientists have a question about what to do with open objects. Should we classify them as planets? And then there will be not 9, but 12 planets in the solar system, or the exclusion of Pluto from the list of planets will solve this issue.

Review of status

When was Pluto removed from the list of planets? On August 25, 2006, participants in the congress of the International Astronomical Union, consisting of 2.5 thousand people, made a sensational decision - to exclude Pluto from the list of planets of the solar system. This meant that many textbooks had to be revised and rewritten, as well as star charts and scientific papers in the field.

Why was this decision made? Scientists have had to reconsider the criteria by which planets are classified. Long debates led to the conclusion that the planet must meet all parameters.

First, the object must be rotating around the Sun in its orbit. Pluto fits this parameter. Although its orbit is highly elongated, it revolves around the Sun.

Secondly, it should not be a satellite of another planet. This point also corresponds to Pluto. At one time it was believed that he appeared, but this assumption was discarded with the advent of new discoveries, and especially of his own satellites.

The third point is to have enough mass to acquire a spherical shape. Pluto, although small in mass, is round, and this is confirmed by photographs.

And finally, the fourth requirement is to have a strong one in order to clear your orbit from others. For this one point, Pluto is not suitable for the role of a planet. It is located in the Kuiper belt and is not the largest object in it. Its mass is not enough to clear its way in orbit.

Now it’s clear why Pluto was excluded from the list of planets. But where should such objects be classified? For such bodies, the definition of “dwarf planets” was introduced. They began to include all objects that do not meet the last point. So Pluto is still a planet, albeit a dwarf one.

Pluto is the name given to the largest “dwarf planet” of our planetary system, the existence of which has been known since ancient times. There are many interesting facts associated with Pluto. Initially, the above-mentioned cosmic body was recognized as a standard planet, but after numerous disputes it was assigned the status of a “dwarf planet.” In addition, Pluto was recognized as the largest Kuiper belt object.

• The “dwarf planet” was named after a dark deity who lived in the underworld. In the myths and legends of Rome, the god Pluto was the son of the god Saturn, who, as we know, ruled the world with his relatives. At the same time, Pluto ruled the underground dark world.
• The atmospheric layer of the “dwarf planet” consists mainly of nitrogen. In addition, it contains methane and carbon monoxide. All of the above substances make Pluto absolutely unsuitable for life for people on Earth.

• Pluto is the only “dwarf” that has an atmospheric layer. When this cosmic object approaches the star (is at perihelion), the above layer becomes gaseous. When the “dwarf planet” moves away from the star as much as possible (is at apohelia), its atmospheric layer gradually freezes, which is why precipitation falls on the surface of the “dwarf planet”.
• Pluto orbits the star the longest. This “dwarf planet” needs 248 Earth years. The fastest planet in this regard, in turn, is the planet Mercury, which flies a full circle around the star in just 88 days.

• In addition, Pluto was recognized as the second slowest rotating cosmic object, since it rotates around its axis in 6 days, 9 hours and 17 minutes. In first place in this ranking is Venus, which makes a full revolution around its axis in 243 days.
• The “dwarf planet” rotates in a direction unusual for us. The luminary there rises in the west and sets in the east. In addition to Pluto, Venus rotates in a similar way, as does Uranus.
• Pluto is not particularly larger than its main satellite, which is Charon. Because of this, some planetary scientists call them a "paired planetary system."

• The light from our star reaches the above-described “dwarf planet” in approximately five hours. For comparison, it will reach our planet in eight minutes.
• In astrology, the “evil dwarf” Pluto means collapse, death and at the same time rebirth.
• If a standard earthling, whose weight is 45 kg, is sent to Pluto, then there he will weigh only a couple of kilograms.
• Living on Pluto, you can see the starry night sky all day long.
• We will not be able to see the “dwarf planet” with the naked eye. You can compare it with a walnut, which has moved away from us at a distance of fifty kilometers. Without special equipment, it is impossible to see a walnut from such a distance.

• The same territories of the “dwarf planet” and its satellite are constantly directed towards each other. Standing on a “dwarf planet,” we will always see one side of Charon. It will seem to us that he is motionless. In fact, Pluto’s satellite and the “dwarf planet” itself revolve around each other absolutely mutually.
• Pluto's most famous satellite (Charon) received its name in honor of the mythical “carrier” who carried the souls of the dead to Hell. In addition to it, the “dwarf planet” has three more satellites: the goddess of the night Nyx, the mythical monster Hydra and the as yet unnamed space object “S/2011 P1”, which was discovered relatively recently, or rather in 2011.
• Pluto has been called a “dwarf planet” since 2006. Before that, for seventy years it was called simply “the planet.”

• Pluto was found in the starry sky and officially discovered in 1930. After that, people were asked to come up with a name for it. The current name was proposed by an 11-year-old ordinary girl named V. Bernie. She explained her decision by saying that this planet was very dark and mysterious. On the first of May the planet received its name, and V. Bernie became the owner of a financial reward of 5 pounds. sterling.
• Many planetary scientists to this day disagree with the fact that Pluto was called a “dwarf.” They believe that if this space object had been closer to the star, it would never have been reclassified.
• In modern times, in scientific circles the planet described above is called “asteroid No. 134340.” The fact is that in astronomical catalogs, “dwarf planets” refer to asteroids.
• On Pluto we will not see the Sun we are used to. From such a distance, the luminary will appear as a tiny dot in the night starry sky. By the way, on the “dwarf planet” the star rises/sets approximately once a week.

The most distant celestial body in the solar system is the dwarf planet Pluto. More recently, school textbooks stated that Pluto is the ninth planet. However, the facts that were obtained during the study of this celestial body at the turn of the millennium forced the scientific community to doubt whether Pluto is a planet. Despite this and many other controversial issues, the small and distant world continues to excite the minds of astronomers, astrophysicists and a huge army of amateurs.

History of the planet Pluto

Back in the 80s of the 19th century, many astronomers tried unsuccessfully to find a certain Planet-X, which, through its behavior, influenced the orbital characteristics of Uranus. The searches were carried out in the most isolated areas of our space, approximately at a distance of 50-100 AU. from the center of the solar system. American Percival Lowell spent more than fourteen years unsuccessfully searching for a mysterious object that continued to excite the minds of scientists.

It will be half a century before the world receives proof of the existence of another planet in the solar system. The discovery of the planet was carried out by Clyde Tombaugh, an astronomer from the Flagstaff Observatory, which was founded by the same restless Lowell. In March 1930, Clyde Tombaugh, observing through a telescope the area of ​​space in which Lowell assumed the existence of a large celestial body, discovered a new fairly large space object.

Subsequently, it turned out that due to its small size and low mass, Pluto is not able to influence the larger Uranus. Oscillations and interaction of the orbits of Uranus and Neptune have a different nature, associated with the special physical parameters of the two planets.

The discovered planet was named Pluto, thereby continuing the tradition of naming the celestial bodies of the Solar System in honor of the gods of the ancient Pantheon. There is another version in the history of the name of the new planet. It is believed that Pluto got its name in honor of Percival Lowell because Tombaugh suggested choosing a name in accordance with the initials of the restless scientist.

Until the end of the 20th century, Pluto firmly occupied a place in the planetary series of the Solar family. Changes in the status of the planet occurred at the turn of the millennium. Scientists have been able to identify a number of other massive objects in the Kuiper belt, which has cast doubt on Pluto's exceptional position. This prompted the scientific world to revise the position of the ninth planet and answer the question of why Pluto is not a planet. In accordance with the new formal definition of the term “planet,” Pluto fell out of the general ensemble. The result of long debates and discussions was the decision of the International Astronomical Union in 2006 to transfer the object to the category of dwarf planets, putting Pluto on a par with Ceres and Eris. A little later, the status of the former ninth planet of the solar system was further lowered, including it in the category of small planets with tail number 134,340.

What do we know about Pluto?

The former ninth planet is considered the most distant of all large celestial bodies known to this day. Such a distant object can only be observed using powerful telescopes or photographs. It is quite difficult to fix a dim small point on the sky, since the planet’s orbit has specific parameters. Periods have been noted when Pluto is at its maximum brightness and its luminosity is 14m. However, in general, the distant wanderer does not differ in bright behavior, and the rest of the time he is practically invisible, and only during the period of oppositions the planet opens itself to observation.

One of the best periods for the study and exploration of Pluto occurred in the 90s of the 20th century. The farthest planet was at the minimum distance from the Sun, closer than its neighbor Neptune.

According to astronomical parameters, the object stands out among the celestial bodies of the Solar System. The baby has the highest orbital eccentricity and inclination. Pluto completes its stellar journey around the main luminary in 250 Earth years. The average orbital speed is the slowest in the Solar System, only 4.7 kilometers per second. In this case, the period of rotation of the small planet around its own axis is 132 hours (6 days and 8 hours).

At perihelion, the object is located at a distance of 4 billion 425 million km from the Sun, and at aphelion it runs away to almost 7.5 billion km. (to be precise - 7375 million km). At such enormous distances, the Sun gives Pluto 1600 times less heat than we, earthlings, receive.

The axis deviation is 122.5⁰, the deviation of Pluto’s orbital path from the ecliptic plane has an angle of 17.15⁰. In simple terms, the planet lies on its side, rolling as it moves around its orbit.

The physical parameters of the dwarf planet are as follows:

• equatorial diameter is 2930 km;
• Pluto's mass is 1.3 × 10²² kg, which is 0.002 Earth's mass;
• the density of the dwarf planet is 1.860 ± 0.013 g/cm³;
• the acceleration of gravity on Pluto is only 0.617 m/s².

The size of the former ninth planet is 2/3 of the diameter of the Moon. Of all the known dwarf planets, only Eris has a larger diameter. The mass of this celestial body is also small, which is six times less than the mass of our satellite.

Dwarf planet retinue

However, despite such a small size, Pluto bothered to get five natural satellites: Charon, Styx, Nikta, Kerberos and Hydra. All of them are listed in order of distance from the mother planet. Charon's size forces it to have the same pressure center as Pluto, around which both celestial bodies revolve. In this regard, scientists consider Pluto-Charon a double planetary system.

The satellites of this celestial body are of different nature. If Charon has a spherical shape, then all the others are huge and shapeless giant stones. It is likely that these objects were captured by Pluto's gravitational field from among the asteroids traveling in the Kuiper Belt.

Charon is Pluto's largest moon, which was discovered only in 1978. The distance between the two objects is 19640 km. At the same time, the diameter of the largest moon of the dwarf planet is 2 times smaller - 1205 km. The ratio of the masses of both celestial bodies is 1:8.

Pluto's other satellites - Niktas and Hydra - are approximately the same in size, but are much inferior in this parameter to Charon. Styx and Nyx are generally barely noticeable objects with dimensions of 100-150 km. Unlike Charon, the remaining four satellites of Pluto are located at a considerable distance from the mother planet.

When observing with the Hubble telescope, scientists were interested in the fact that Pluto and Charon have significantly different colors. Charon's surface appears darker than Pluto's. Presumably, the surface of the dwarf planet's largest satellite is covered with a thick layer of cosmic ice, consisting of frozen ammonia, methane, ethane and water vapor.

Atmosphere and brief description of the structure of the dwarf planet

With the presence of natural satellites, Pluto can be considered a planet, albeit a dwarf one. To a large extent, this is facilitated by the presence of Pluto’s atmosphere. Of course, this is not an earthly paradise with a high content of nitrogen and oxygen, but Pluto still has an air blanket. The atmospheric density of this celestial object varies depending on its distance from the Sun.

People first started talking about Pluto's atmosphere in 1988, when the planet passed through the solar disk. Scientists admit that the dwarf's air-gas envelope appears only during the period of its closest approach to the Sun. When Pluto moves significantly away from the center of the solar system, its atmosphere freezes. Judging by spectral images obtained from the Hubble Space Telescope, the composition of Pluto's atmosphere is approximately the following:

• nitrogen 90%;
• carbon monoxide 5%;
• methane 4%.

The remaining one percent comes from organic compounds of nitrogen and carbon. The strong rarefaction of the planet's air-gas shell is evidenced by data on atmospheric pressure. On Pluto it varies from 1-3 to 10-20 microbars.

The surface of the planet has a characteristic slightly reddish tint, which is caused by the presence of organic compounds in the atmosphere. After studying the resulting images, polar caps were discovered on Pluto. It is possible that we are dealing with frozen nitrogen. Where the planet is covered in dark spots, there are likely vast fields of frozen methane that are darkened by sunlight and cosmic radiation. The alternation of light and dark spots on the surface of the dwarf indicates the presence of seasons. Like Mercury, which also has a very thin atmosphere, Pluto is covered with craters of cosmic origin.

The temperatures in this distant and dark world are very low and incompatible with life. On the surface of Pluto there is eternal cosmic cold with a temperature of 230-260⁰С below zero. Due to the planet's recumbent position, the planet's poles are considered the warmest areas. While vast areas of Pluto's surface are a permafrost zone.

As for the internal structure of this distant celestial body, a typical picture is possible here, characteristic of the terrestrial planets. Pluto has a fairly large and massive core consisting of silicates. Its diameter is estimated at 885 km, which explains the rather high density of the planet.

Interesting facts about the research of the former ninth planet

The huge distances that separate Earth and Pluto make it very difficult to study and research using technical means. Earthlings will have to wait about ten Earth years for the spacecraft to reach Pluto. Launched in January 2006, the New Horizons space probe was able to reach this region of the solar system only in July 2015.

For five months, as the automatic station “New Horizons” approached Pluto, photometric studies of this region of space were actively carried out.

Flight of the New Horizons probe

This device was the first to fly in close proximity to a distant planet. The previously launched American Voyager probes, the first and second, focused on studying larger objects - Jupiter, Saturn and its moons.

The flight of the New Horizons probe made it possible to obtain detailed images of the surface of the dwarf planet numbered 134,340. The study of the object was carried out from a distance of 12 thousand km. Not only detailed photographs of the surface of a distant planet, but also photographs of all five of Pluto’s moons were received on Earth. Until now, work is underway in NASA laboratories to detail the information received from the spacecraft, as a result of which in the future we will receive a clearer picture of that world distant from us.

Pluto– dwarf planet of the solar system: discovery, name, size, mass, orbit, composition, atmosphere, satellites, which planet Pluto is, research, photos.

Pluto- the ninth or former planet of the solar system, which has become a dwarf planet.

In 1930, Clyde Tomb discovered Pluto, which became the 9th planet for a century. But in 2006, it was moved to the family of dwarf planets, because many similar objects were found beyond Neptune. But this does not negate its value, because now it ranks first in size among the dwarf planets in our system.

In 2015, the New Horizons spacecraft reached it, and we received not only close-up photos of Pluto, but also a lot of useful information. Let's look at interesting facts about the planet Pluto for children and adults.

Interesting facts about the planet Pluto

Namereceived in honor of the lord of the underworld

• This is a later variation of the name Hades. It was proposed by an 11-year-old girl, Venice Brunei.

Became a dwarf planet in 2006

• At this point, the IAU puts forward a new definition of “planet” - a celestial object that is on an orbital path around the Sun, has the necessary mass for a spherical shape and has cleared its surroundings of foreign bodies.

• In the 76 years between discovery and shift to dwarf type, Pluto managed to travel only a third of its orbital route.

There are 5 satellites

• The lunar family includes Charon (1978), Hydra and Nyx (2005), Kerberos (2011) and Styx (2012).

Largest dwarf planet

• Previously it was believed that Eris deserves this title. But now we know that its diameter reaches 2326 km, and Pluto’s is 2372 km.

1/3 consists of water

• Pluto's composition is represented by water ice, where there is 3 times more water than in Earth's oceans. The surface is covered with an ice crust. Ridges, light and dark areas, as well as a chain of craters are noticeable.

Smaller in size than some satellites

• The larger moons are considered to be Gynimed, Titan, Io, Callisto, Europa, Triton and the earth's satellite. Pluto reaches 66% of the lunar diameter and 18% of the mass.

Endowed with an eccentric and inclined orbit

• Pluto lives at a distance of 4.4-7.3 billion km from our star the Sun, which means it sometimes comes closer than Neptune.

Received one visitor

• In 2006, the New Horizons spacecraft set off for Pluto, arriving at the object on July 14, 2015. With its help, it was possible to obtain the first approximate images. Now the device is moving towards the Kuiper belt.

Pluto's position predicted mathematically

• This happened in 1915 thanks to Percival Lowell, who was based on the orbits of Uranus and Neptune.

An atmosphere arises periodically

• As Pluto approaches the Sun, the surface ice begins to melt and forms a thin layer of atmosphere. It is represented by nitrogen and methane haze with an altitude of 161 km. The sun's rays break down the methane into hydrocarbons, which cover the ice with a dark layer.

Discovery of the planet Pluto

Pluto's presence was predicted even before it was found in the survey. In the 1840s Urbain Verrieres used Newtonian mechanics to calculate the position of Neptune (then not yet found), based on the displacement of the orbital path of Uranus. In the 19th century, a close study of Neptune showed that its peace was also disturbed (the transit of Pluto).

In 1906, Percival Lowell founded the search for Planet X. Unfortunately, he passed away in 1916 and did not live to see the discovery. And he didn’t even suspect that Pluto was displayed on two of his plates.

In 1929, the search resumed, and the project was entrusted to Clyde Tomb. The 23-year-old spent a year taking pictures of the sky and then analyzing them to find when objects moved.

In 1930, he found a possible candidate. The observatory requested additional photographs and confirmed the presence of the celestial body. On March 13, 1930, a new planet in the solar system was discovered.

Planet name Pluto

After the announcement, the Lowell Observatory began receiving an influx of letters suggesting names. Pluto was the Roman deity in charge of the underworld. This name came from 11-year-old Venice Bernie, who was suggested by her astronomer grandfather. Below are photos of Pluto from the Hubble Space Telescope.

It was officially named on March 24, 1930. Among the competitors were Minevra and Kronus. But Pluto was a perfect fit, since the first letters reflected the initials of Percival Lowell.

We quickly got used to the name. And in 1930, Walt Disney even named Mickey Mouse's dog Pluto after the object. In 1941, the element plutonium was introduced by Glenn Seaborg.

Size, mass and orbit of the planet Pluto

With a mass of 1.305 x 10 22 kg, Pluto ranks second in terms of mass among dwarf planets. The area indicator is 1.765 x 10 7 km, and the volume is 6.97 x 10 9 km 3.

Physical characteristics of Pluto
Equatorial radius	1153 km
Polar radius	1153 km
Surface area	1.6697 10 7 km²
Volume	6.39 10 9 km³
Weight	(1.305 ± 0.007) 10 22 kg
Average density	2.03 ± 0.06 g/cm³
Acceleration of free fall at the equator	0.658 m/s² (0.067 g)
First escape velocity	1.229 km/s
Equatorial rotation speed	0.01310556 km/s
Rotation period	6.387230 seed. days
Axis tilt	119.591 ± 0.014°
North pole declination	−6.145 ± 0.014°
Albedo	0,4
Apparent magnitude	up to 13.65
Angular diameter	0.065-0.115″

Now you know what kind of planet Pluto is, but let's study its rotation. The dwarf planet moves along a moderately eccentric orbital path, approaching the Sun at 4.4 billion km and moving away at 7.3 billion km. This suggests that it sometimes comes closer to the Sun than Neptune. But they have a stable resonance, so they avoid collision.

It takes 250 years to pass around a star, and completes an axial revolution in 6.39 days. The inclination is 120°, resulting in remarkable seasonal variations. During the solstice, ¼ of the surface is continuously warmed, and the rest is in darkness.

Composition and atmosphere of the planet Pluto

With a density of 1.87 g/cm3, Pluto has a rocky core and an icy mantle. The composition of the surface layer is 98% nitrogen ice with a small amount of methane and carbon monoxide. An interesting formation is the Heart of Pluto (Tombaugh Region). Below is a diagram of the structure of Pluto.

Researchers think the object's interior is divided into layers, with a dense core filled with rocky material and surrounded by a mantle of water ice. In diameter, the core extends over 1,700 km, which covers 70% of the entire dwarf planet. The decay of radioactive elements indicates a possible subsurface ocean with a thickness of 100-180 km.

The thin atmospheric layer is composed of nitrogen, methane and carbon monoxide. But the object is so cold that the atmosphere freezes and falls to the surface. The average temperature reaches -229°C.

Moons of Pluto

The dwarf planet Pluto has 5 moons. The largest and closest is Charon. It was found in 1978 by James Christie, who was looking at old photographs. Behind it are the remaining moons: Styx, Nikta, Kerberos and Hydra.

In 2005, the Hubble telescope found Nix and Hydra, and in 2011, Kerberos. Styx was noticed already during the flight of the New Horizons mission in 2012.

Charon, Styx and Kerberos have the necessary mass to form as spheroids. But Nyx and Hydra seem elongated. The Pluto-Charon system is interesting because their center of mass is located outside the planet. Because of this, some are inclined to believe in a double dwarf system.

In addition, they reside in a tidal block and are always turned on one side. In 2007, water crystals and ammonia hydrates were noticed on Charon. This suggests that Pluto has active cryogeysers and an ocean. The satellites could have formed due to the impact of Plato and a large body at the very beginning of the solar system.

Pluto and Charon

Astrophysicist Valery Shematovich about the icy moon of Pluto, the New Horizons mission and the Charon ocean:

Classification of the planet Pluto

Why isn't Pluto considered a planet? In orbit with Pluto in 1992, similar objects began to be noticed, which led to the idea that the dwarf belonged to the Kuiper belt. This made me wonder about the true nature of the object.

In 2005, scientists discovered a trans-Neptunian object - Eris. It turned out that it was larger than Pluto, but no one knew whether it could be called a planet. However, this became the impetus for the planetary nature of Pluto to be doubted.

In 2006, the IAU began a dispute over the classification of Pluto. The new criteria required being in solar orbit, having enough gravity to form a sphere, and clearing the orbit of other objects.

Pluto failed on the third point. At the meeting it was decided that such planets should be called dwarfs. But not everyone supported this decision. Alan Stern and Mark Bye were actively opposed.

In 2008, another scientific discussion was held, which did not lead to a consensus. But the IAU approved the official classification of Pluto as a dwarf planet. Now you know why Pluto is no longer a planet.

Exploring the planet Pluto

Pluto is difficult to observe because it is tiny and very far away. In the 1980s NASA began planning for the Voyager 1 mission. But they still focused on Saturn’s moon Titan, so they were unable to visit the planet. Voyager 2 also did not consider this trajectory.

But in 1977, the question of reaching Pluto and trans-Neptunian objects was raised. The Pluto-Kuiper Express program was created, which was canceled in 2000 because funding ran out. The New Horizons project was launched in 2003 and departed in 2006. In the same year, the first photos of the object appeared when testing the LORRI instrument.

The device began approaching in 2015 and sent photos of the dwarf planet Pluto at a distance of 203,000,000 km. Pluto and Charon were displayed on them.

The closest approach happened on July 14, when we managed to get the best and most detailed footage. Now the device is moving at a speed of 14.52 km/s. With this mission we received a huge amount of information that has yet to be digested and realized. But it is important that we also better understand the process of system formation and other similar objects. Next, you can carefully study the map of Pluto and photos of its surface features.

Click on the image to enlarge it

Photos of the dwarf planet Pluto

The beloved little one is no longer a planet and has taken its place in the dwarf category. But High resolution photos of Pluto demonstrate a very interesting world. First of all, we are greeted by the “heart” - the plain captured by Voyager. This is a crater world that was previously considered the coldest, most distant and small 9th ​​planet. Pictures of Pluto will also demonstrate the large satellite Charon, with which they resemble a double planet. But space It doesn’t end there, because further on there are many more ice objects.

"Badlands" by Pluto

Magnificent Crescent Moon of Pluto

Blue sky of Pluto

Mountain ranges, plains and foggy hazes

Smoke layers over Pluto

Ice plains in high resolution

This high-resolution photo was obtained by New Horizons on December 24, 2015, showing the territory of Sputnik Planitia. This is the part of the image where the resolution is 77-85 m per pixel. You can see the cellular structure of the plains, which could have been caused by a convective explosion in the nitrogen ice. The image captured a strip 80 km wide and 700 km long, stretching from the northwestern part of Sputnik Planitia to the icy part. Performed using the LORRI instrument at a distance of 17,000 km.

Second mountain range found in Pluto's heart

Floating hills on Sputnik Plain

The diversity of Pluto's landscape

New Horizons obtained this high-resolution photo of Pluto (July 14, 2015), which is considered the best magnification, with a scale of up to 270 m. The section extends over 120 kilometers and is taken from a large mosaic. The surface of the plain can be seen surrounded by two isolated ice mountains.

Wright Mons in color

New Horizons team reacts to the latest photo of Pluto

Heart of Pluto

Complex surface features of Sputnik Plain

You can't imagine how many people were upset when the decision was made to stop considering Pluto a planet in the solar system. Children whose beloved cartoon dog Pluto suddenly began to be named after who knows what. Let us remember that in ancient Greek mythology this is one of the names of the god of death. Chemists and nuclear physicists were saddened because they gave this name to plutonium, a radioactive element capable of destroying all of humanity. What about astrologers? Unhappy charlatans have been fooling people for decades, describing how much influence this demoted object has on their fate and character, and it’s good if indignant clients do not make claims of a material nature.

When did Pluto stop being considered a planet?

Be that as it may, Pluto ceased to be considered a planet in 2006. We must come to terms with this and live with the awareness of this fact. Does not work? Okay, then let's forget about feelings and try to look at the situation from a logical point of view, which is what science always calls us to do.

The demotion of Pluto took place at the 26th General Assembly of the International Astronomical Society, held in Prague, and this decision caused many disputes and objections. Some scientists wanted to keep it as a planet, but the only argument they could give to justify their desire was that “it would break tradition.” The fact is that there is not, and there has never been, any scientific basis to consider Pluto a planet. This is just one of the objects of the Kuiper belt - a huge cluster of heterogeneous celestial bodies located beyond the orbit of Neptune. There are about a trillion of these objects there. And they are all blocks of stone and ice, just like Pluto. He is simply the first of those that we managed to see.

It is certainly very large compared to most of its neighbors, but it is not the largest object in the Kuiper Belt. This is Eris, which, even if it is inferior to Pluto in size, is very little, so small that debate about which of them is larger continues to this day. But it is a quarter heavier. This object is located twice as far from the Sun as Pluto. There are many other similar celestial bodies in the Solar System. These are Haumea, Makemane, and Ceres, which is located in the asteroid belt between Mars and Jupiter. According to scientists, we may have about a hundred of these strong creatures in total. Waiting to be noticed.

No imagination is enough here. Neither animators nor chemists. Astrologers should have enough, but few serious people care about their interests. This is precisely the main reason why we stopped considering Pluto a planet. Because together with it, we, in theory, should elevate so many celestial bodies to this rank that the word “planet” itself will lose its current meaning. In this regard, in the same 2006, astronomers defined clear criteria for objects claiming this status.

What are the criteria for a “planet”?

They must orbit the Sun, have sufficient gravity to bring themselves into a more or less spherical shape, and almost completely clear their orbit of other objects. Pluto was cut off at the last point. Its mass is equal to only 0.07% of the mass of everything that is on its circular path. To give you an idea of ​​how insignificant this is, the mass of the Earth is 1,700,000 times greater than the mass of other matter in its orbit.

Earth, Moon, Pluto for comparison

It must be said that the International Astronomical Society was not entirely heartless. It came up with a new category for celestial bodies that satisfy only the first two criteria. Now these are dwarf planets. And as a sign of respect for the place that Pluto once occupied in our worldview and in our culture, it was decided to call the dwarf planets located further than Neptune “plutoids.” Which is, of course, quite nice.

And in the same year that astronomers decided that Pluto could no longer be called a planet, NASA launched the New Horizons spacecraft, whose mission included visiting this celestial body. As of this moment in time, this interplanetary station has completed its task, transmitting to Earth a lot of valuable data about Pluto, as well as picturesque photographs of this dwarf planet. Don't be lazy, find them on the Internet.
Let's hope that humanity's interest in Pluto will not end there. It is, after all, on our way to other stars and galaxies. We're not going to sit in our solar system forever.