Planets of the solar system and their arrangement in order. Complete revolution of the planets Time of revolution of the planets

Planets of the Solar System

According to the official position of the International Astronomical Union (IAU), the organization that assigns names to astronomical objects, there are only 8 planets.

Pluto was removed from the planet category in 2006. because There are objects in the Kuiper belt that are larger/equal in size to Pluto. Therefore, even if we take it as a full-fledged celestial body, then it is necessary to add Eris to this category, which has almost the same size as Pluto.

By MAC definition, there are 8 known planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

All planets are divided into two categories depending on their physical characteristics: terrestrial group and gas giants.

Schematic representation of the location of the planets

Terrestrial planets

Mercury

The smallest planet in the solar system has a radius of only 2440 km. The period of revolution around the Sun, equated to an earthly year for ease of understanding, is 88 days, while Mercury manages to rotate around its own axis only one and a half times. Thus, his day lasts approximately 59 Earth days. For a long time it was believed that this planet always turned the same side to the Sun, since periods of its visibility from Earth were repeated with a frequency approximately equal to four Mercury days. This misconception was dispelled with the advent of the ability to use radar research and conduct continuous observations using space stations. The orbit of Mercury is one of the most unstable; not only the speed of movement and its distance from the Sun change, but also the position itself. Anyone interested can observe this effect.

Mercury in color, image from the MESSENGER spacecraft

Its proximity to the Sun is the reason why Mercury is subject to the largest temperature changes among the planets in our system. The average daytime temperature is about 350 degrees Celsius, and the nighttime temperature is -170 °C. Sodium, oxygen, helium, potassium, hydrogen and argon were detected in the atmosphere. There is a theory that it was previously a satellite of Venus, but so far this remains unproven. It does not have its own satellites.

Venus

The second planet from the Sun, the atmosphere is almost entirely composed of carbon dioxide. She is often called Morning star and the Evening Star, because it is the first of the stars to become visible after sunset, just as before dawn it continues to be visible even when all the other stars have disappeared from view. The percentage of carbon dioxide in the atmosphere is 96%, there is relatively little nitrogen in it - almost 4%, and water vapor and oxygen are present in very small quantities.

Venus in the UV spectrum

Such an atmosphere creates a greenhouse effect; the temperature on the surface is even higher than that of Mercury and reaches 475 °C. Considered the slowest, a Venusian day lasts 243 Earth days, which is almost equal to a year on Venus - 225 Earth days. Many call it Earth's sister because of its mass and radius, the values ​​of which are very close to those of Earth. The radius of Venus is 6052 km (0.85% of Earth's). Like Mercury, there are no satellites.

The third planet from the Sun and the only one in our system where there is liquid water on the surface, without which life on the planet could not have developed. At least life as we know it. The radius of the Earth is 6371 km and, unlike other celestial bodies in our system, more than 70% of its surface is covered with water. The rest of the space is occupied by continents. Another feature of the Earth is tectonic plates, hidden under the planet's mantle. At the same time, they are able to move, albeit at a very low speed, which over time causes changes in the landscape. The speed of the planet moving along it is 29-30 km/sec.

Our planet from space

One revolution around its axis takes almost 24 hours, and a complete passage through the orbit lasts 365 days, which is much longer in comparison with its closest neighboring planets. The Earth's day and year are also accepted as a standard, but this is done only for the convenience of perceiving time periods on other planets. The Earth has one natural satellite - the Moon.

Mars

The fourth planet from the Sun, known for its thin atmosphere. Since 1960, Mars has been actively explored by scientists from several countries, including the USSR and the USA. Not all exploration programs have been successful, but water found at some sites suggests that primitive life exists on Mars, or existed in the past.

The brightness of this planet allows it to be seen from Earth without any instruments. Moreover, once every 15-17 years, during the Confrontation, it becomes the brightest object in the sky, eclipsing even Jupiter and Venus.

The radius is almost half that of Earth and is 3390 km, but the year is much longer - 687 days. He has 2 satellites - Phobos and Deimos .

Visual model of the solar system

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• Sun

  The Sun is a star that is a hot ball of hot gases at the center of our Solar System. Its influence extends far beyond the orbits of Neptune and Pluto. Without the Sun and its intense energy and heat, there would be no life on Earth. There are billions of stars like our Sun scattered throughout the Milky Way galaxy.

• Mercury

  Sun-scorched Mercury is only slightly larger than Earth's satellite the Moon. Like the Moon, Mercury is practically devoid of an atmosphere and cannot smooth out the traces of impact from falling meteorites, so it, like the Moon, is covered with craters. The day side of Mercury gets very hot from the Sun, while on the night side the temperature drops hundreds of degrees below zero. There is ice in the craters of Mercury, which are located at the poles. Mercury completes one revolution around the Sun every 88 days.

• Venus

  Venus is a world of monstrous heat (even more than on Mercury) and volcanic activity. Similar in structure and size to Earth, Venus is covered in a thick and toxic atmosphere that creates a strong Greenhouse effect. This scorched world is hot enough to melt lead. Radar images through the powerful atmosphere revealed volcanoes and deformed mountains. Venus rotates in opposite direction, from the rotation of most planets.

• Earth is an ocean planet. Our home, with its abundance of water and life, makes it unique in our solar system. Other planets, including several moons, also have ice deposits, atmospheres, seasons and even weather, but only on Earth did all these components come together in a way that made life possible.

• Mars

  Although details of the surface of Mars are difficult to see from Earth, observations through a telescope indicate that Mars has seasons and white spots at the poles. For decades, people believed that the bright and dark areas on Mars were patches of vegetation, that Mars might be a suitable place for life, and that water existed in the polar ice caps. When the Mariner 4 spacecraft arrived at Mars in 1965, many scientists were shocked to see photographs of the murky, cratered planet. Mars turned out to be a dead planet. More recent missions, however, have revealed that Mars holds many mysteries that remain to be solved.

• Jupiter

  Jupiter is the most massive planet in our solar system, with four large moons and many small moons. Jupiter forms a kind of miniature solar system. To become a full-fledged star, Jupiter needed to become 80 times more massive.

• Saturn

  Saturn is the farthest of the five planets known before the invention of the telescope. Like Jupiter, Saturn is composed primarily of hydrogen and helium. Its volume is 755 times greater than that of the Earth. Winds in its atmosphere reach speeds of 500 meters per second. These fast winds, combined with heat rising from the planet's interior, cause the yellow and golden streaks we see in the atmosphere.

• Uranus

  The first planet found using a telescope, Uranus was discovered in 1781 by astronomer William Herschel. The seventh planet is so far from the Sun that one revolution around the Sun takes 84 years.

• Neptune

  Distant Neptune rotates almost 4.5 billion kilometers from the Sun. It takes him 165 years to complete one revolution around the Sun. It is invisible to the naked eye due to its vast distance from Earth. Interestingly, its unusual elliptical orbit intersects with the orbit of the dwarf planet Pluto, which is why Pluto is inside the orbit of Neptune for about 20 years out of 248 during which it makes one revolution around the Sun.

• Pluto

  Tiny, cold and incredibly distant, Pluto was discovered in 1930 and was long considered the ninth planet. But after discoveries of Pluto-like worlds that were even further away, Pluto was reclassified as a dwarf planet in 2006.

Planets are giants

There are four gas giants located beyond the orbit of Mars: Jupiter, Saturn, Uranus, Neptune. They are located in the outer solar system. They are distinguished by their massiveness and gas composition.

Planets of the solar system, not to scale

Jupiter

The fifth planet from the Sun and the largest planet in our system. Its radius is 69912 km, it is 19 times larger than the Earth and only 10 times smaller than the Sun. The year on Jupiter is not the longest in the solar system, lasting 4333 Earth days (less than 12 years). His own day has a duration of about 10 Earth hours. The exact composition of the planet's surface has not yet been determined, but it is known that krypton, argon and xenon are present on Jupiter in much larger quantities than on the Sun.

There is an opinion that one of the four gas giants is actually a failed star. This theory is supported by the most a large number of Jupiter has many satellites – as many as 67. To imagine their behavior in the planet’s orbit, you need a fairly accurate and clear model of the solar system. The largest of them are Callisto, Ganymede, Io and Europa. Moreover, Ganymede is the largest satellite of the planets in the entire solar system, its radius is 2634 km, which is 8% greater than the size of Mercury, the smallest planet in our system. Io has the distinction of being one of only three moons with an atmosphere.

Saturn

The second largest planet and the sixth in the solar system. Compared to other planets, its composition is most similar to the Sun chemical elements. The radius of the surface is 57,350 km, the year is 10,759 days (almost 30 Earth years). A day here lasts a little longer than on Jupiter - 10.5 Earth hours. In terms of the number of satellites, it is not much behind its neighbor - 62 versus 67. The largest satellite of Saturn is Titan, just like Io, which is distinguished by the presence of an atmosphere. Slightly smaller in size, but no less famous are Enceladus, Rhea, Dione, Tethys, Iapetus and Mimas. It is these satellites that are the objects for the most frequent observation, and therefore we can say that they are the most studied in comparison with the others.

For a long time, the rings on Saturn were considered a unique phenomenon unique to him. Only recently it was established that all gas giants have rings, but in others they are not so clearly visible. Their origin has not yet been established, although there are several hypotheses about how they appeared. In addition, it was recently discovered that Rhea, one of the satellites of the sixth planet, also has some kind of rings.

On March 13, 1781, English astronomer William Herschel discovered the seventh planet of the solar system - Uranus. And on March 13, 1930, American astronomer Clyde Tombaugh discovered the ninth planet of the solar system - Pluto. By the beginning of the 21st century, it was believed that the solar system included nine planets. However, in 2006, the International Astronomical Union decided to strip Pluto of this status.

60 are already known natural satellites Saturn, most of which were discovered using spacecraft. Most of the satellites consist of rocks and ice. The largest satellite, Titan, discovered in 1655 by Christiaan Huygens, is larger than the planet Mercury. The diameter of Titan is about 5200 km. Titan orbits Saturn every 16 days. Titan is the only moon to have a very dense atmosphere, 1.5 times larger than Earth's, consisting primarily of 90% nitrogen, with moderate methane content.

The International Astronomical Union officially recognized Pluto as a planet in May 1930. At that moment, it was assumed that its mass was comparable to the mass of the Earth, but later it was found that Pluto’s mass is almost 500 times less than the Earth’s, even less than the mass of the Moon. Pluto's mass is 1.2 x 10.22 kg (0.22 Earth's mass). Pluto's average distance from the Sun is 39.44 AU. (5.9 to 10 to 12 degrees km), radius is about 1.65 thousand km. The period of revolution around the Sun is 248.6 years, the period of rotation around its axis is 6.4 days. Pluto's composition is believed to include rock and ice; the planet has a thin atmosphere consisting of nitrogen, methane and carbon monoxide. Pluto has three moons: Charon, Hydra and Nix.

At the end of the 20th and beginning of the 21st centuries, many objects were discovered in the outer solar system. It has become obvious that Pluto is only one of the largest Kuiper Belt objects known to date. Moreover, at least one of the belt objects - Eris - is a larger body than Pluto and is 27% heavier. In this regard, the idea arose to no longer consider Pluto as a planet. On August 24, 2006, at the XXVI General Assembly of the International Astronomical Union (IAU), it was decided to henceforth call Pluto not a “planet”, but a “dwarf planet”.

At the conference, a new definition of a planet was developed, according to which planets are considered bodies that revolve around a star (and are not themselves a star), have a hydrostatically equilibrium shape and have “cleared” the area in the area of ​​their orbit from other, smaller objects. Dwarf planets will be considered objects that orbit a star, have a hydrostatically equilibrium shape, but have not “cleared” the nearby space and are not satellites. Planets and dwarf planets are two different classes of objects in the Solar System. All other objects orbiting the Sun that are not satellites will be called small bodies of the Solar System.

Thus, since 2006, there have been eight planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. The International Astronomical Union officially recognizes five dwarf planets: Ceres, Pluto, Haumea, Makemake, and Eris.

On June 11, 2008, the IAU announced the introduction of the concept of "plutoid". It was decided to call celestial bodies revolving around the Sun in an orbit whose radius is greater than the radius of Neptune’s orbit, whose mass is sufficient for gravitational forces to give them an almost spherical shape, and which do not clear the space around their orbit (that is, many small objects revolve around them) ).

Since it is still difficult to determine the shape and thus the relationship to the class of dwarf planets for such distant objects as plutoids, scientists recommended temporarily classifying all objects whose absolute asteroid magnitude (brilliance from a distance of one astronomical unit) is brighter than +1 as plutoids. If it later turns out that an object classified as a plutoid is not a dwarf planet, it will be deprived of this status, although the assigned name will be retained. The dwarf planets Pluto and Eris were classified as plutoids. In July 2008, Makemake was included in this category. On September 17, 2008, Haumea was added to the list.

The material was prepared based on information from open sources

solar system - a planetary system that includes the central star - the Sun - and all natural space objects, rotating around it. The bulk of the solar system's mass is concentrated in the Sun - 99.8%. That is why the Sun holds all objects in the solar system by gravity.

All objects of the Solar system are officially divided into three categories: planets, dwarf planets and small bodies of the solar system.

Planet- any body in orbit around the Sun that turns out to be massive enough to acquire a spherical shape, but not massive enough to initiate thermonuclear fusion, and has managed to clear the vicinity of its orbit from small bodies. By this definition, there are eight known planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

The four smaller inner planets: Mercury, Venus, Earth and Mars, also called the terrestrial planets, are composed primarily of silicates and metals. The four outer planets: Jupiter, Saturn, Uranus and Neptune, also called gas giants, are largely composed of hydrogen and helium and are much more massive than the terrestrial planets. Pluto does not meet this definition because it has not cleared its orbit of surrounding Kuiper belt objects, so on August 24, 2006, the International Astronomical Union (IAU) officially revoked Pluto's planet status.

Dwarf planet- a celestial body orbiting the Sun, which is massive enough to maintain a close to round shape under the influence of its own gravitational forces, but which has not cleared the space of its orbit from small bodies and is not a satellite of the planet. By this definition, the Solar System has five recognized dwarf planets: Ceres, Pluto, Haumea, Makemake, and Eris.

There are two regions in the solar system filled with small bodies. The asteroid belt, located between Mars and Jupiter, is similar in composition to the terrestrial planets, since it consists of silicates and metals. The largest objects in the asteroid belt are Ceres, Pallas and Juno.

Kuiper Belt- the region of the Solar System from the orbit of Neptune (30 AU from the Sun) to a distance of about 55 AU. e from the Sun. Although the Kuiper Belt is similar to the asteroid belt, it is about 20 times wider and 20 to 200 times more massive. Like the asteroid belt, it consists mainly of small bodies, that is, material left over from the formation of the Solar System. Unlike asteroid belt objects, which are primarily composed of rocks and metals, Kuiper belt objects are composed primarily of volatile substances (called ices) such as methane, ammonia, and water. This region of near space contains at least three dwarf planets: Pluto, Haumea and Makemake.

Most large objects orbiting the Sun move in essentially the same plane, called the ecliptic plane. All planets and most other objects orbit the Sun in the same direction as the Sun's rotation (counterclockwise when viewed from the side north pole Sun). There are exceptions, such as Halley's Comet. Mercury has the highest angular velocity - it manages to complete a full revolution around the Sun in just 88 Earth days. And for the most distant planet - Neptune - the orbital period is 165 Earth years.

Most of the planets rotate around their axis in the same direction as they revolve around the Sun. The exceptions are Venus and Uranus, and Uranus rotates almost “lying on its side” (axis tilt is about 90°). The orbits of objects around the Sun are described Kepler's laws. According to them, each object rotates according to ellipse, in one of the focuses of which the Sun is located. Objects closer to the Sun have a higher angular velocity of rotation, so their orbital period is shorter ( year). In an elliptical orbit, an object's distance from the Sun varies throughout its year. The point in an object's orbit closest to the Sun is called perihelion, the most distant - aphelion. Each object moves fastest at its perihelion and slowest at its aphelion. The orbits of the planets are close to circles, but many comets, asteroids and Kuiper belt objects have highly elongated elliptical orbits.

The Solar System moves through the Milky Way galaxy in a circular orbit approximately 30,000 light-years from the galactic center at a speed of 254 km/s. The period of revolution around the center of the galaxy, the so-called galactic year, is approximately 200 million years for the Solar System.

Table 1 Comparative table of the main parameters of the planets

Let's consider how long it takes for planets to complete their revolution when they return to the same point in the zodiac where they were.

Periods of complete rotation of planets

Sun - 365 days 6 hours;

Mercury - approximately 1 year;

Venus - 255 days;

Moon - 28 days (according to the ecliptic);

Mars - 1 year 322 days;

Lilith - 9 years old;

Jupiter - 11 years 313 days;

Saturn - 29 years 155 days;

Chiron - 50 years old;

Uranus - 83 years 273 days;

Neptune - 163 years 253 days;

Pluto - approximately 250 years;

Proserpine - about 650 years old.

The farther a planet is from the Sun, the longer way which she describes around him. Planets that complete a revolution around the Sun take more than human life, in astrology are called high planets.

If the time of complete revolution is completed in the average lifespan of a person, these are low planets. Accordingly, their influence is different: low planets mainly influence the individual, each person, while high planets mainly influence many lives, groups of people, nations, countries.

How do planets rotate completely?

The movement of the planets around the Sun occurs not in a circle, but in an ellipse. Therefore, during its movement, the planet is at different distances from the Sun: a closer distance is called perihelion (the planet in this position moves faster), a further distance is called aphelion (the speed of the planet slows down).

To simplify the calculation of the movement of the planets and the average speed of their movement, astronomers conventionally assume the trajectory of their movement in a circle. Thus, it is conventionally accepted that the movement of planets in orbit has a constant speed.

Considering the different speeds of movement of the planets of the solar system and their different orbits, to the observer they appear to be scattered across the starry sky. It seems that they are located on the same level. In fact, this is not so.

It should be remembered that the constellations of the planets are not the same as the signs of the Zodiac. Constellations are formed in the sky by clusters of stars, and the signs of the Zodiac are symbols of a 30-degree section of the Zodiac sphere.

Constellations can occupy an area of ​​less than 30° in the sky (depending on the angle at which they are visible), and the Zodiac sign occupies this entire area (the zone of influence begins at 31 degrees).

What is a parade of planets

There are rare cases when the location of many planets, when projected onto the Earth, is close to a straight line (vertical), forming clusters of planets in the solar system in the sky. If this happens with nearby planets, it is called a small parade of planets, if with distant ones (they can join the nearby ones), it is a large parade of planets.

During the “parade”, the planets, gathered in one place in the sky, seem to “gather” their energy into a beam, which has a powerful influence on the Earth: natural disasters occur more often and much more pronounced, powerful and radical transformations in society, mortality increases (heart attacks, strokes, train accidents, accidents, etc.)

Features of planetary motion

If we imagine the Earth, motionless in the center, around which the planets of the solar system revolve, then the trajectory of the planets accepted in astronomy will be sharply disrupted. The Sun revolves around the Earth, and the planets Mercury and Venus, located between the Earth and the Sun, will revolve around the Sun, periodically changing their direction to the opposite - this “retrograde” movement is designated “R” (retrograde).

Finding and between is called lower opposition, and in the opposite orbit behind is called upper opposition.

Records of periodic comets

• The comet with the greatest brightness is Halley's Comet, named after the English astronomer Edmond Halley (1656 - 1742), who established the periodic nature of its return to the Sun and correctly predicted its next appearance.
• The comet with the shortest period of orbit around the Sun is Comet Encke, discovered in 1786 and named after the German astronomer Johann Encke (1791 - 1865), who established the periodic nature of its return to the Sun and correctly predicted its next appearance. The orbital period of Comet Encke around the Sun is 3.3 years. (Comet Wilson-Harrington, discovered in 1949, had an estimated orbital period of 2.3 years, but was never observed again.)
• The comet with the longest period of revolution around the Sun is Comet Herschel-Rigolet, discovered in 1788 and named after its discoverers. The comet's orbital period is 156 years.
• The comet with the most circular orbit is Comet Schwassmann-Wachmann-1, discovered in 1925 and named after its discoverers. The eccentricity of its orbit is 0.11. All the orbits of the major planets, with the exception of Mercury and Pluto, have significantly less eccentricity.
• The comet with the most elongated orbit is Comet Brorsen-Metkoff, discovered in 1847 and named after its discoverers. The eccentricity of the comet's orbit is 0.972, i.e. its maximum distance from the Sun is almost 70 times greater than its minimum distance from the Sun. Among the most numerous group of comets with an orbital period of less than 20 years, Comet Encke has the most elongated orbit. The eccentricity of its orbit is 0.85, i.e. its maximum distance from the Sun is 12 times greater than its minimum.
• The comet with the greatest orbital inclination to the ecliptic is Comet Toutle, which was first observed in 1790, but is named after the American astronomer who rediscovered it in 1858. Its orbit is located at an angle of 54.4° to the ecliptic. Among the most numerous group of comets with an orbital period of less than 20 years, the greatest inclination of the orbit to the ecliptic is the comet Giacobini-Zinner - 31.7°, discovered in 1900 and named after its discoverers.
• The comet with the smallest orbital inclination to the ecliptic is Comet Kojima, discovered in 1970 and named after its discoverer. The comet's orbit is located at an angle of 54" to the ecliptic.
• The comet with the longest perihelion distance is Comet Schwassmann-Wachmann-1. Its minimum distance from the Sun is 5.45 astronomical units, i.e. Comet Schwassmann-Wachmann-1 is always located further from the Sun than Jupiter.
• The comet that approaches the Sun at the shortest distance is Comet Encke. It is 51 million km, i.e. approximately 7 million km less than the average distance of Mercury from the Sun.
• The comet that moves the greatest distance from the Sun is Halley's Comet. It is 35.33 astronomical units, i.e. almost 800 million km more than the average distance of Neptune from the Sun. Among the most numerous group of comets with an orbital period of less than 20 years, comet Neuimin-1, discovered in 1913 and named after its discoverer, moves farthest from the Sun. Its aphelion distance is 12.2 astronomical units.
• The comet with the shortest aphelion distance is Comet Encke. It moves away from the Sun to a maximum distance of 4.1 astronomical units; this is one astronomical unit less than the average distance of Jupiter from the Sun.
• The comet that approached the Earth at the closest distance was Comet Lexel, discovered in 1770 and named after the Russian astronomer who calculated its orbit. The minimum distance was 1.2 million km; at that moment it was clearly visible to the naked eye.
• The largest comet was observed in 1811. The diameter of the coma was approximately 2 million km, i.e. one and a half times larger than the sun, and its tail extended over a distance exceeding the astronomical unit.
• The comet with the largest number of tails is the comet discovered on December 9, 1743 by the Dutch astronomer Klinkenberg and, independently, on December 13 by the Swiss astronomer De Chézeau. She had at least six bright, wide tails.
• The comet observed the largest number of times is Comet Encke. In 2003, she returned for the 59th time. In terms of the number of returns, it was far ahead of other comets.
• The first known passage of the Earth through the tail of a comet occurred at the end of June 1861. It was the tail of a comet discovered by Australian astronomer J. Tebbutt. No effects associated with passing through the comet's tail were recorded.
• The first attempt to observe the passage of a comet (Halley's Comet) across the disk of the Sun was made on May 18-19, 1910 by the American astronomer F. Ellerman in the Hawaiian Islands - a place with the best atmospheric conditions for observations. However, no traces of the comet could be seen on the solar disk.

In addition to periodic comets, non-periodic comets have been observed hundreds of times in the earth's sky, appearing only once, which have blocked some of the records indicated here.