HOW WAS NEPTUNE AND PLUTO DISCOVERED?

After the discovery of Uranus, astronomers believed for decades that it was the "extreme" planet in the solar system. The movement of Uranus was followed by telescopes from year to year and, based on these observations, the position of the planet was calculated for many years to come. But it turned out that the calculations did not coincide with the observations. The attraction of all the other planets was taken into account, but there were still some unforeseen perturbations in the motion of Uranus. And then astronomers suggested that this irregularity in the movement of Uranus must have depended on some other planet orbiting the Sun at an even greater distance from it. The task arose: by the perturbation that the unknown planet produces, to find its position in space. Scientists D. Adams in England and W. Le Verrier in France independently solved this problem. The orbit of the eighth planet was calculated, its coordinates were determined for a certain moment of time, and on September 23, 1846, astronomer I. Galle discovered a planet in the indicated place, which was not on the star map. The eighth planet of the solar system was named Neptune in honor of the god of the seas in Roman mythology. The discovery of this planet was a triumph of celestial mechanics, a triumph of the heliocentric system.

Since not all deviations in the movement of Uranus were explained by the influence of the planet Neptune, the search for the source of the perturbing force was continued, and in 1930, using a telescope and studying photographs, an unknown planet was discovered and named Pluto (in Roman mythology, the god of the underworld).

The discovery of the ninth planet in the solar system belongs to the American astronomer Clyde Tombaugh.

The most distant planet in the solar system is Neptune, located at a distance of 4.5 billion km from the Sun. After Pluto was removed from the category of planets in 2006, Neptune began to be considered the most distant planet from the Sun.

Differences between these celestial bodies

They are fundamentally different from each other. The dwarf planet is a tiny Kuiper Belt Object, a rocky ball of ice only 2,390 km across. Its diameter is a small fraction of the diameter of the gas giant, which is 49,500 km across.

These celestial bodies show very interesting orbital dynamics and relationships with each other. The gas giant has an almost circular orbit, while Pluto has a large eccentricity, its distance from the Sun varies throughout its orbit.

Due to this, it periodically comes closer to the Sun than Neptune. The last time this happened was in 1979 and continued until 1999. During this period, Neptune was the most distant planet from the Sun. And in 2006, when Pluto was downgraded to a dwarf planet, Neptune finally became the most distant planet in the solar system.

Pluto has been within the orbit of the eighth planet for nearly 20 out of 248 years

Photo of Pluto - a mosaic assembled from images of the planet taken by the automatic interplanetary station (AMS) "New Horizons" on July 14, 2015 from a distance of 450,000 km

Since their orbits intersect, is it possible that these two planets will collide? No, because the dwarf planet passes much higher above the plane of the Sun's orbit. When it is at the same point in its orbit as Neptune, it is actually much taller. Thus, these two planets never intersect.

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Discovery of Uranus, Neptune and Pluto

Uranus and Neptune on the celestial sphere

Uranus . The third largest planet in the solar system, Uranus is visible from Earth as a 6th magnitude star. Since 1690, astronomers have shown it as a star on their charts several times. However, it was discovered as a planet only almost two centuries after the invention of the telescope, by the musician and amateur astronomer William Herschel.

Herschel was a native of Germany, at the age of 19, escaping from recruitment in the army, he emigrated to England. After many hardships and hardships, he rose to prominence as a performing musician, composer and music teacher in the seaside resort town of Bath near Bristol. In addition to music, Herschel's passion was astronomy.

Disappointed in a small reflector acquired in 1773 with a focal length of 2.5 feet, he made with his own hands a reflector almost 2 meters long and a main mirror 20 cm in diameter. And with the help of his new instrument, he began in 1775 a survey of the entire sky visible from Bath. Between music lessons, Herschel polished metal mirrors for telescopes, gave concerts in the evenings, and spent his nights observing the stars.

Herschel telescope

Having completed the survey of the entire sky, Herschel decided to repeat it. On March 13, 1781, he studied the location of the stars in the region of the constellation Taurus. One of the stars within this area seemed strange to him - instead of a bright point, it looked like a small disk, so he made the following entry in his observation diary: "of an unusual appearance - either a star surrounded by a nebula, or a comet." Herschel believed he had discovered a new comet and sent a letter to the Royal Society. After 2 months, Academician Andrei Leksel of St. Petersburg calculated the parameters of the orbit of this celestial body, which showed that it revolves around the Sun in a circle whose radius is 19 times greater than the radius of the Earth's orbit. The resulting orbit looked more like a planet than a comet. It became clear that for the first time since the Babylonian priests a new planet had been discovered in the solar system.

William Herschel

Herschel suggested that the newly discovered celestial body be called the planet George in honor of King George III, who ruled at that time in England. However, this name did not take root, and another name became generally accepted - Uranus, proposed in the year of the discovery of the planet by the German astronomer Johann Bode, who believed that it was necessary to continue the historical tradition of planet names from ancient Roman mythology in the outer parts of the solar system. Thanks to the discovery of Uranus, William Herschel was able to become a professional astronomer, and then the largest observing astronomer in history. In the same year that Uranus was discovered, Herschel was elected a Fellow of the Royal Society of London and received a doctorate from Oxford University.

Six years later, in 1787, Herschel discovered the two largest satellites of Uranus Oberon and Titania - objects of 13-14 magnitude. Two more satellites were found in 1851 by the prosperous Liverpool brewer William Lassell, an eminent British amateur astronomer of the Victorian era. Finally, in 1948, American astronomer Gerard Kuiper found the smallest of the five main moons, Miranda.

The first four satellites did not get their names from the discoverers. Names were given to them in the 19th century by the son of William Herschel, John Herschel, who himself was one of the most prominent astronomers in the world. In violation of the astronomical tradition, which requires taking names for planets and satellites from the mythological plots of different peoples, the satellites received the names of characters from the works of English writers - Shakespeare and Pope. The brightest among the satellites of Uranus - Ariel received the name of the kind, bright spirit of the air - a character found both in Shakespeare's play "The Tempest" and in Pop's poem "The Kidnapping of the Lock". The satellite next to him - Umbriel, twice as dark, was named after an evil, dark spirit from the same poem by Pop. The two largest of Uranus' moons, Titania and Oberon, were named after the queen of the fairies and her husband, the king of good spirits from Shakespeare's A Midsummer Night's Dream.

Uranus and its moons

When a new chemical element was discovered in 1789, which turned out to be the heaviest element known at that time, it was named "uranium" in honor of the discovered planet. Only a century and a half after the discovery of this element, it became a key element in nuclear physics and technology. When new elements with atomic numbers 93 and 94, at that time the last in the periodic table, were obtained from uranium (atomic number 92) in the twentieth century, they were named after the planets following uranium: neptunium (after the planet Neptune) and plutonium (after the planet Pluto).

Neptune . Soon after the discovery of Uranus in 1781 by W. Herschel, incomprehensible anomalies began to be revealed in the movement of this planet - it either “lagged behind” the calculated position, then it was ahead of it. Russian astronomer Academician Andrei Leksel, who proved that the object discovered by Herschel is a planet, drew attention to the anomalies in the motion of Uranus back in 1783. After studying the features of the planet's motion, Leksel suggested that Uranus is affected by the attraction of an unknown cosmic body, whose orbit is located even further from the Sun.

In 1821, the French astronomer Alexis Bouvard published tables of the position of Uranus for many years to come. But over the next 10 years, the data from direct observations of Uranus increasingly diverged from Bouvard's tables, which caused the scientific community to explain this phenomenon.

This question was of great interest to the 22-year-old student of Cambridge College, John Adams (1819-1892). And he suggested that some invisible and not yet known planet, located beyond Uranus, is to blame for this. The fact that it could influence the movement of Uranus followed from Newton's law of universal gravitation.

Fascinated by this problem, Adams decided to calculate the orbit of an unknown planet from the deviations of Uranus, determine its mass and indicate its location in the sky. Thus, for the first time in the history of astronomy, man set himself the most difficult task: to discover a new planet in the solar system with the help of Newton's law and the methods of higher mathematics.

The task was much more difficult than it seemed at first glance. The difficulties were aggravated by the fact that in those days not only were there no computers, but there were also not enough auxiliary mathematical tables. For 16 months, Adams was busy calculating the orbit of an unknown planet. Finally, having completed his painstaking work, he indicated the place in the constellation of Aquarius where the planet was supposed to be on October 1, 1845.

Adams wanted to report the results of his calculations to the Royal Astronomer George Erie (1801-1892). But, to his chagrin, the meeting with Eri, on which he placed so many hopes, did not take place. Instead of a detailed report, I had to confine myself to a short note. When Eri read it, he had doubts. Meanwhile, the results of the calculations were extremely accurate: the unknown planet was only 2 degrees from the place indicated by Adams. And if astronomers had wished then to search for it, the planet would not have gone unnoticed. But Adams's work lay in the Astronomer Royal's desk, and no one knew about it.

In parallel with this summer of 1845, F. Arago, director of the Paris Observatory and head of French astronomy at that time, suggested that W. Le Verrier take up the "problem of Uranus." At this time neither he nor Arago they did not know that Adams had been working on it for two years in England, and that he had already received significant results.

In November 1845 Le Verrier published the first article on Uranus. He rebuilt the entire theory of the motion of Uranus, taking into account perturbations from known planets, refining everything that had been done by Bouvard. His work and the nature of the presentation itself were distinguished by thoroughness, taking into account the finest details, and clarity. The perturbations of Uranus' orbit were calculated by two different methods, which ensured that there were no errors. Finally, the accuracy of the calculated coordinates of Uranus was 0,1.

It turned out that Adams and Le Verrier, not knowing anything about each other, began a mathematical search for an unknown planet almost simultaneously. In the summer of 1846, Le Verrier made a report at the French Academy of Sciences on the results of studying the deviations of Uranus. He proved that the cause of these deviations is not Jupiter or Saturn, but an unknown planet located beyond Uranus. But the most interesting thing was that in terms of the position of the new planet in the sky, Le Verrier's calculations almost completely coincided with those of Adams.

It was only now that George Erie realized that he had mistrusted Adams's work in vain. And he asked the Cambridge University Observatory to examine a section of the starry sky in the constellation Aquarius, where, according to mathematical calculations, an unknown planet should have “hidden”.

Neptune in the constellation Aquarius

Unfortunately, neither England nor France yet had a detailed star map of the studied area of ​​the sky, and this made it very difficult to search for a distant planet.

Then Le Verrier wrote a letter to the Berlin Observatory to Johann Galle (1812-1910) with a request to immediately start searching for a transuranic planet.

Galle, who had the right star map, decided not to waste time. On the same night - September 23, 1846 - he began to observe. The search lasted about half an hour. Finally, Galle saw a faint star, which was not on the map. At high magnification, it appeared as a small disk. The next night Galle continued his observations. During the day, the mysterious object moved noticeably among the stars. Now there was no doubt: yes, it was she - a new planet!

The discovery of Neptune was extremely important, because it finally confirmed the validity of the heliocentric system of the world of Nicolaus Copernicus. At the same time, the validity and universality of the law of universal gravitation was proved.

Pluto . Taking into account the influence of Neptune on Uranus made it possible to reduce the discrepancies between the theoretical and observed motion of Uranus by dozens of times, but it was not possible to achieve full accuracy. In 1848, the American astronomer B. Pierce suggested the existence of a ninth planet. In 1874, S. N'kom built a new theory of the motion of Uranus, taking into account perturbations from Jupiter, Saturn and Neptune. He also assumed the existence transneptunian planets.

First started searching transneptunian(ninth) planet famous American astronomer Percival Lovell (1855-1916). Having carefully studied its possible influence on the motion of Uranus, he calculated the orbit of the proposed planet, determined its mass and conventionally called it Planet X.

“The ninth planet,” Lovell wrote, “is located at 6 billion km from the Sun, and it takes 282 years to complete one revolution around the Sun. Lovell believed that this is a relatively small planet, which is visible from Earth as faint telescopic star. Judging by the results of the calculations, the planet was "hiding" in the zodiac constellation Gemini.

At the beginning of 1905, Lovell, using a 5-inch astrograph (a special telescope equipped with a photographic camera), began photographing sections of the starry sky in Gemini. He exposed each plate for three hours and then developed it. The plates produced images of stars, including stars of the 16th magnitude. The brightness of such stars is 10 thousand times weaker than the brightness of the faintest stars visible to the naked eye. After several nights, the astronomer made repeated photographs of the same parts of the starry sky.

Then came the most important stage of research. The negatives, on which the same sections of the sky were photographed, were carefully superimposed on each other by Lovell so that the images of the stars coincided. He carefully examined each pair of combined negatives through a magnifying glass.

Searches in the last years of his life greatly weakened the health of the astronomer, he died in 1916.

Ironically, 15 years later, in Lovell's photographs taken in 1914-1915, "planet X" was nevertheless discovered. An astronomer, looking for an object with a magnitude of 12-13 magnitudes, simply did not pay attention to a star of 15 magnitudes.

After that, the interest of astronomers in the search for the ninth planet began to fall. Only at the Lovell Observatory were further searches planned. In the late 1920s, Lovell's brother, Abbot Lawrence, made an additional financial contribution to the observatory's fund. Part of this money went to a new wide-field 32.5 cm telescope capable of photographing stars up to magnitude 17 in an area of ​​160 square degrees within an hour, i.e. 1/260 of the entire visible sky. The new chamber began work on April 1, 1929.

A young employee of the observatory Clyde William Tombaugh (1906-1997) took an active part in the work on the telescope. In early April 1929, Clyde Tombaugh, using a 13-inch astrograph, began photographing the stars in the constellation Gemini, where, according to Lovell's calculations, the planet X should be located. Every clear night he photographed a certain section of the starry sky, and two or three nights later he received a second plate with an image of the same section. To ensure that nothing went unnoticed, Clyde applied an almost flawless search technique: he photographed all parts of the starry sky three times.

Clyde Tombaugh

Hundreds of thousands, no, millions of stars have already been captured! And in this stellar ocean it was necessary to find a barely noticeable planet. To do this, Clyde compared paired negatives on a special device - blink microscope. The device was designed in such a way that it allowed one to view two plates in turn, on which the same section of the starry sky was photographed. If a moving object was photographed on the plates, then with a quick change of images, it seemed to jump from one place to another, while "fixed" stars do not experience displacements. Thanks to this method (the “blinking” method), Tombo hoped to find a small point, lost among millions of stars, the planet X.

Clyde is completely gone in search. With his characteristic energy, he worked 14 hours a day: at night he photographed the starry sky, and during the day he compared the plates, carefully examining each “suspicious” image. Images of millions of stars have already been viewed. New asteroids, variable stars, galaxies discovered... And no sign of Planet X! When will he finally find her? Or is he really wasting his time? But Clyde every time drove away doubts and with even greater perseverance began to search.

February 18, 1930 Clyde Tombaugh, as always, examined the next pair of records, filmed in the last decade of January. Suddenly, near the star of the Gemini delta, one of the weak points jumped. He had already observed shifts of asteroids more than once, but this shift was not like all the previous ones - it was very small. Judging by the magnitude of the shift, the unknown object was very far from the Earth and from the Sun. Clyde's heart began to beat violently, and he shouted, “Here she is! It must be Planet X!”

More than 100,000 alleged images of the planet were in fact photographic defects, and each such "marriage" had to be rechecked on the third picture. Finally, in the photographs of the vicinity of the star Delta Gemini, taken on January 21, 23, 29, 1930, Tombo discovered a slowly moving "star-like" object. Subsequent observations confirmed that it was not a comet or an asteroid. On March 13, the director of the Lovell Observatory, V. M. Slifer, announced the discovery of a new planet. This news immediately spread on the radio all over the world.

Discovery of Pluto

Even through a large telescope, the object discovered by Tombo looked like a faint 15th-magnitude star with no sign of a planetary disk. And to make sure it's real transneptunian planet, astronomers began to closely monitor its movement. Several weeks have passed. Observations have shown that it moves exactly as it should be for a planet beyond Neptune to move.

On March 13, 1930, on the day of the 75th anniversary of the birth of Lovell, who initiated the search for Planet X, the world learned about its discovery.

The discovery of Pluto was a new triumph of scientific foresight. The boundaries of the planetary system were moved away from the Sun immediately by 1.5 billion km!

Pluto and its moons (photo from the Hubble Space Telescope)

Many thought the planet should be named Lovell, but in the end, the Lovell Observatory settled on the name Pluto, proposed by the 11-year-old daughter of Oxford astronomy professor Venesha Burney. According to Greco-Roman mythology, Pluto (Hades) was the ruler of a dark underworld kingdom, and it was quite appropriate to assign his name to a planet from the kingdom of darkness on the periphery of the solar system. The name took on a new symbolic meaning when, in 1945, the chemical element plutonium, named after the newly discovered planet, became the basis for the first atomic bombs.

Possible view of Pluto's surface

For 76 years after its discovery, Pluto was considered the ninth planet in the solar system. On the edge XX and XXI centuries beyond the orbit of Pluto, many other planets were discovered, some of which turned out to be even larger than Pluto in size. In this regard, at the congress of the International Astronomical Union in 2006, Pluto was recognized as one of the objects of the Kuiper belt and received the status of a "dwarf planet".

Questions and tasks

1. How were Uranus, Neptune and Pluto discovered? Name their discoverers. Where did their names come from?

2. Where did the name of the chemical elements come from - uranium, neptunium, plutonium?

3. Why was it possible to discover Uranus only in XVIIIcentury, although it can be seen with the naked eye?

4. Why is the discovery of Neptune considered the final confirmation of the Copernican heliocentric system?

5. What was the main difficulty in finding Pluto?

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Sun Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune

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The story of the discovery of Uranus is a planet that for many centuries was considered the most distant planet. By the 40s of the XIX century. accurate observations have shown that Uranus deviates just barely from the path it should follow, given the perturbations from all the known planets. Thus the theory of motion of celestial bodies, so rigorous and precise, was put to the test. Urbain Le Verrier and John Couch Adams suggested that if perturbations from the known planets do not explain the deviation in the motion of Uranus, then it means that the attraction of an as yet unknown body is acting on it. ..

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... Scientists almost simultaneously calculated where behind Uranus there should be an unknown body that produces these deviations with its attraction. They calculated the orbit of the unknown planet, its mass and indicated the place in the sky where the unknown planet should have been at the given time. This planet was found in a telescope at the place indicated by them in 1846. They named her Neptune...

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The atmosphere consists of hydrogen, helium and methane On Neptune, the fastest winds in the solar system, they accelerate to 2,200 km / h Neptune was named after the god of the seas in Roman mythology And now a little about Pluto ...

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The first to search for the ninth planet was the famous American astronomer Percival Lowell (1855-1916). Having carefully studied its possible influence on the motion of Uranus, he calculated the orbit of the proposed planet, determined its mass and conventionally called it Planet X. After Lovell's death, the search for the ninth planet was continued by Clyde Tombaugh. On February 18, 1930, Clyde Tombaugh, as always, examined another pair of records, filmed in the last decade of January. Suddenly, near the star of the Gemini delta, one of the weak points jumped. He had already observed shifts of asteroids more than once, but this shift was not like all the previous ones - it was very small. Judging by the magnitude of the shift, the unknown object was very far from the Earth and from the Sun. Clyde's heart skipped a beat and he screamed, "Here it is! This must be Planet X!" March 13, 1930, on the day of the 75th anniversary of the birth of Lovell, who initiated the search for Planet X, the world learned about its discovery. The new planet was named Pluto - after the god of the underworld. This name was quite suitable for a planet moving far from the Sun - on the very outskirts of the planetary system ...

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Why is Pluto no longer considered a planet? Pluto was officially recognized as a planet by the International Astronomical Union in May 1930. At that moment, it was assumed that its mass was comparable to the mass of the Earth, in reality, Pluto's mass is almost 500 times less than the Earth's, even less than the mass of the Moon ... ... Recently, it has become obvious that Pluto is just one of the larger Kuiper belt objects, with one of the belt objects being a larger body than Pluto (27% heavier). In this regard, the idea arose not to consider Pluto as a planet anymore, which caused heated debate ... Finally, on August 24, 2006, at the XXVI General Assembly of the International Astronomical Union, it was decided to continue to call Pluto not a "planet", but a "dwarf planet".

In the XVIII century, the planetary system was studied even before the planet Saturn. Although scientists have assumed that even more distant planets exist, planets such as Uranus, Neptune and Pluto. The famous British astronomer William Herschel in 1781, observing the stars through a telescope, noticed a new luminary, previously unnoticed by the naked eye. After some time of observation, he realized that he had discovered a new planet. The new planet was named Uranus.

Uranus is the seventh planet, slightly less than 2900 million km from the Sun. Uranus revolves around the Sun in 84 Earth years. The speed of rotation of Uranus around the Sun is 7 km / s, while the Earth revolves around the Sun at a speed of 30 km / s.

Uranus is a fairly bright planet and if you know exactly where to look, you can see it with the naked eye. It changes its position among the stars and, despite the fact that it does not twinkle, looks like a star. Uranus is the only planet that rotates "lying on its side". It is believed that this position was determined millions of years ago as a result of a collision with a large body.

Uranus is smaller than Saturn but much larger than Earth. The temperature on Uranus is minus 200 degrees and below. There is a small stone core in the center of the planet. The cloudy atmosphere of Uranus is mostly hydrogen-helium, and also contains methane. Due to the presence of a large amount of helium in the upper atmosphere, Uranus has a blue-green color. In 1977, it was discovered that Uranus has rings made of dust. Uranus makes a full rotation around its axis faster than the Earth in 18 hours.

In 1846, German astronomer Johann Gottfried Galle discovered Neptune, the eighth planet in the solar system. He made his discovery by pointing the telescope exactly at the place indicated by the results of their calculations by the French astronomer Le Verrier and the English scientist Adams.
This discovery confirmed the correctness of the system of the world of Copernicus and the laws of motion and attraction of Newton, on which all calculations performed in celestial mechanics are based.

Neptune is more than 4500 million km from the Sun. It completes one revolution around the Sun in 165 Earth years.
The temperature on the surface of Neptune is also less than minus 200 degrees.

Neptune is a planet - a gas giant, but in size it is slightly smaller than Uranus. Neptune completes a complete revolution around its axis in 16 hours. Scientists believe that Neptune is made up of a mixture of water, rocks, liquid ammonia, and methane.
In addition to hydrogen, helium and water, Neptune's thick cloudy atmosphere contains methane gas, thanks to which Neptune has a blue color and is called the "Blue Planet".

Violent storms rage in Neptune's atmosphere. Long thin clouds rush over Neptune. They are driven by such violent winds as are not found on any other planet in the solar system. The wind speed can reach 2000 km/h. Therefore, Neptune is also called the "Planet of Storms".
Neptune is not visible to the naked eye, it can only be seen with binoculars as a small star.

Pluto differs sharply from the giant planets. It was discovered in 1930 by the American astronomer Clyde Timbo. The mass of Pluto is about the same as the mass of the Earth. Of all the planets, Pluto is almost always the farthest from the Sun. It revolves around the Sun in a highly elongated oval orbit. Therefore, the distance of Pluto from the Sun varies greatly: from 4425 to 7375 million km. Out of every 249 years, only 20 years Pluto is closer to the Sun than Neptune.

Pluto's diameter is about 2300 km. Even in the most powerful ground-based telescopes, Pluto looks like a star. It is not yet possible to examine its surface. Judging by the photographs, the surface of Pluto is covered with frozen methane and nitrogen. Perhaps there is a thin layer of the atmosphere.

Planet cycles Uranus, Neptune and Pluto long, and in astrology it is believed that they affect entire generations of people, animals and the growth of perennial plants: trees and shrubs. A person born in one of the cycles of these planets is quite likely to become a genius.

Uranus was named after the ancient Roman god of heaven. In astrology, Uranus is considered the planet of the future, unexpected events, unusual phenomena. He patronizes everything new, original thoughts and inventions, the human genius that creates these inventions, new opportunities for new discoveries.
Uranus affects our creative individuality and personal "I", the desire for friendship, freedom and independence. Uranus directs entire teams in creativity.

The planet Neptune is associated in astrology with the oceans. Neptune in mythology is the God of the seas and oceans. He governs all expanses of water, as well as all processes and phenomena hidden under water. Neptune influences the weather by adjusting the amount of precipitation as it sees fit.
Astrologers believe that Neptune affects heredity, the world of the subconscious, imagination, and the spiritual component of the personality.

Pluto got its name in honor of the ancient Roman god of the underworld and the souls of dead people.
In astrology, Pluto symbolizes death and rebirth. It is also believed that Pluto communicates with the World Mind.
Pluto has a powerful impact on generations, exerting an extreme impact on collectives, communities and individuals, exciting an explosion of uncontrollable energy in them. Pluto promotes destructive processes, but always after that creates the conditions for a new revival.