Planets of the solar system

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

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

As defined by MAC, 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 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, for ease of understanding, equated to the earth's year, is 88 days, while Mercury has time to complete a revolution around its own axis only one and a half times. Thus, its day lasts approximately 59 Earth days. For a long time it was believed that this planet is always turned to the Sun by the same side, since the periods of its visibility from the Earth were repeated with a frequency approximately equal to four Mercury days. This misconception was dispelled with the advent of the possibility of using radar research and conducting 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, as seen by the MESSENGER spacecraft

Mercury's proximity to the Sun has caused it to experience the largest temperature fluctuations of any of 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 have been identified in the atmosphere. There is a theory that it was previously a satellite of Venus, but so far this remains unproven. It has no satellites of its own.

Venus

The second planet from the Sun, the atmosphere of which is almost entirely composed of carbon dioxide. It is often called the 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 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 amounts.

Venus in the UV spectrum

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

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 develop. At least life as we know it. The radius of the Earth is 6371 km and, unlike the rest of the celestial bodies in our system, more than 70% of its surface is covered with water. The rest of the space is occupied by the continents. Another feature of the Earth is the 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 a change in the landscape. The speed of the planet moving along it is 29-30 km / s.

Our planet from space

One rotation around its axis takes almost 24 hours, and a complete orbit lasts 365 days, which is much longer in comparison with the nearest neighboring planets. The Earth day and year are also taken as a standard, but this is done only for the convenience of perceiving time intervals on other planets. The Earth has one natural satellite, the Moon.

Mars

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

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

The radius is almost half that of the 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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• The sun

  The sun is a star, which 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 moon. Like the Moon, Mercury is practically devoid of an atmosphere and cannot smooth out the traces of impact from the fall of meteorites, therefore, like the Moon, it is covered with craters. The day side of Mercury is very hot on the Sun, and on the night side the temperature drops hundreds of degrees below zero. In the craters of Mercury, which are located at the poles, there is ice. Mercury makes one revolution around the Sun in 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 mighty atmosphere revealed volcanoes and deformed mountains. Venus rotates in the 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 such a way that life became possible.

• Mars

  Although details of the surface of Mars are difficult to see from Earth, telescope observations show that Mars has seasons and white spots at the poles. For decades, people have assumed that the bright and dark areas on Mars are patches of vegetation and that Mars might be a suitable place for life, and that water exists in the polar caps. When the Mariner 4 spacecraft flew by Mars in 1965, many of the scientists were shocked to see pictures of the bleak, cratered planet. Mars turned out to be a dead planet. More recent missions, however, have shown that Mars holds many mysteries that have yet to be solved.

• Jupiter

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

• Saturn

  Saturn is the most distant of the five planets that were known before the invention of the telescope. Like Jupiter, Saturn is made up mostly of hydrogen and helium. Its volume is 755 times 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 with 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

  Nearly 4.5 billion kilometers from the Sun, distant Neptune rotates. It takes 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 Neptune's orbit for about 20 out of 248 years during which it makes one revolution around the Sun.

• Pluto

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

The planets are giants

There are four gas giants located beyond the orbit of Mars: Jupiter, Saturn, Uranus, Neptune. They are in the outer solar system. They differ in 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. A year on Jupiter is not the longest in the solar system, lasting 4333 Earth days (incomplete 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 also supported by the largest number of satellites, of which Jupiter has many - as many as 67. To imagine their behavior in the orbit of the planet, a fairly accurate and clear model of the solar system is needed. The largest of them are Callisto, Ganymede, Io and Europa. At the same time, Ganymede is the largest satellite of the planets in the entire solar system, its radius is 2634 km, which is 8% larger 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 largest in the solar system. In comparison with other planets, the composition of chemical elements is most similar to the Sun. The surface radius 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 far 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 than it, but no less famous for this - 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 rest.

For a long time, the rings on Saturn were considered a unique phenomenon, inherent only to him. Only recently it was found that all gas giants have rings, but the rest 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.

Finding planets in outer space is an extremely difficult task. Unlike stars, they do not have significant radiation, so their detection is possible by changing the glow of the parent star or by the gravitational influence on other space objects. Evidence of the difficulty of finding them is the ongoing dispute between scientists around an undiscovered massive space object of a planetary type, located at a distance from other planets in the solar system.

In 1846, the German astronomer Johann Gottfried Galle, using Newtonian mechanics and the calculations of the French mathematician Urbain Le Verrier, analyzed strange perturbations in the orbit of Uranus. As a result, he suggested that another planet must be hiding behind Uranus. In the same year, Galle and his student managed to calculate the location and discover a planet unknown until that moment - Neptune. Subsequently, studying the orbits of Uranus and Neptune, astronomers again found strange deviations that could only indicate that another planet was hiding in the distance.

Percival Lowell at work

The search for trans-Neptunian planets captured the minds of astronomers around the world, but the most ambitious search was organized in 1894 by a wealthy businessman and amateur astronomer from Boston, Percival Lowell. Having built a telescope advanced for that time at his own expense, he spent 22 years of his life to find the hypothetical "planet X", as the astronomer himself called it. It is interesting that in those days he really gave shades of mystery and mysticism to the letter X, but in the distant future this name acquired a completely different meaning. The obsession with finding a mysterious planet that influenced the orbits of known objects in the solar system exhausted Lowell mentally and physically, and in 1916 he died, and his unique observatory was abandoned for many years due to the struggle for the businessman's inheritance.

It wasn't until 1925 that an updated telescope lifted its lenses back into the starry sky in search of the elusive planet. This time, the research was led by a 22-year-old farmer with an unexpected talent for astronomy, Clyde Tombaugh. The results of his painstaking work led to the fact that on February 18, 1930 he discovered Pluto.

The excited scientific community began to calculate the parameters of Pluto, based on data on the disturbances it causes in the orbits of other planets. On the telescopes of that time, Pluto looked like a barely noticeable pale dot. Scientists were confused by the size of the discovered planet and its low luminosity, but given its powerful gravitational influence, they suggested that Pluto must have been a very dense and massive planet with little light reflection.

But the farther into the future, the more perfect the methods of observing Pluto became, and the clearer it became that this object does not have either a large mass or a large magnitude. In the end, when it turned out that the mass of Pluto is only 0.22% of the mass of the Earth, it was completely excluded from the list of planets and it was recognized that Pluto could in no way influence the deviations of the orbits of Uranus and Neptune. Lowell also got it - his guess about the location of planet X in the very region where Pluto was located was recognized as accidental.

For many years, the search for the 9th planet of the solar system has become the lot of amateur astronomers. And in 1980, the probability of its existence dropped to a minimum: using modern gravitational theories and computer systems, recalculations of the perturbations of the orbits of Uranus and Neptune were carried out, which showed that these perturbations are extremely small and, quite likely, are within the statistical error. Interest in finding an unknown planet in the solar system finally faded. But everything changed when the Kuiper Belt was discovered in 1987.

The Kuiper belt is a region of the solar system from the orbit of Neptune, which is located at a distance of 30 AU. from the Sun to 55 AU

The Kuiper belt is filled with many small space objects, probably left over from the formation of the solar system, when the planets collided and whirled in a majestic waltz as they formed their orbits around the Sun. Over time, the remaining “building material” was thrown out by gravitational forces into a zone called the Kuiper belt. By the way, Pluto was one of the first to be ranked among the objects of the Kuiper belt, giving it the title of a dwarf planet.

With modern telescopes, astronomers have been able to see hundreds of new, small objects in the Kuiper Belt that had hitherto been impossible to see. But here's the strange thing - the orbits of some of them ran in a very unusual way, while others did not rotate at all in the direction in which they were supposed to! Is it possible that the influence of the very “planet X” can be traced here?

But scientists still cannot answer this question. Every year, more and more new observations and calculations are carried out, the planet search area is gradually narrowing, scanty perturbations of the orbits of Uranus and Neptune, differences from the calculated trajectories of spacecraft that have gone beyond the solar system, and thousands of other parameters are taken into account, but this does not bring success. But on the other hand, scientists were able to calculate the possible parameters of an unknown planet in the solar system: most likely, it is a gas giant with a mass of 10-20 Earth masses and has a radius that is 4-5 times larger than our planet. The period of rotation of the 9th planet around the Sun is about 15,000 Earth years, and the distance from our star can be about 200 AU. Computer modeling of the emergence of the solar system shows that theoretically in 4 or 5 cases out of 20,000 such a planet could form and be captured by the Sun, but, as you can see, the chances of this are extremely small. But still, some scientists continue to believe in its existence. From the latest news - objects were discovered in the Kuiper belt, the specific angle of inclination of which can tell us about the gravitational effect on them of some massive cosmic body ...

And yet, if planet X exists, can it somehow affect the Earth? Of course, the gravitational forces of any space objects in one way or another spread and affect other objects, but the distance to planet X is so great that any of its sensitive influence on the Earth or other planets of the solar system is absolutely excluded. And even more so, you should not wait for the end of the world, assigning mystical properties to the planet like the famous Nibiru. In any case, even with the presence of the 9th planet, our solar system is a mechanism honed over billions of years that works like a clock and has formed unique living conditions for the existence of human civilization.

Illustration: depositphotos | suzbah

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TVNZ:
"It is 10 times larger than the Earth and 7 times farther from the Sun than Neptune
This discovery was announced by scientists from the California Institute of Technology in Pasadena Konstantin Batygin and Mike Brown. The name for the planet has not yet been invented and astronomers have dubbed it simply - Planet X. However, no one has yet seen it, including the godfathers.
Planet X was discovered by mathematical analysis of the gravitational effects experienced by Kuiper belt objects. This is a region far from the Sun, where small and large asteroids and dwarf planets rotate in large numbers. These celestial bodies were left here as construction debris after the formation of the solar system.
- Studying the orbits of these celestial bodies, we came to the conclusion that some kind of hidden giant has a clear effect on their trajectory, - said Brown. - Having compiled a computer model, we calculated the parameters of the invisible planet.

In principle, in astronomy this is a common thing. In much the same way, scientists predicted the existence of Uranus and Pluto long before their visual discovery.
It turned out that the mass of Planet X is 10 times the mass of the Earth. And it revolves around the Sun in a very elongated orbit. At the moment of closest approach to our luminary, the invisible planet and the star are separated by 200 astronomical units (an astronomical unit is the distance from the Sun to the Earth - ed.). At this point, Planet X is 7 times further from the center of the Solar System than Neptune. And the farthest point of the orbit is at 1200 AU. from the sun. It is because of the great distance that astronomers have never observed Planet X through a telescope. The 9th planet makes a complete revolution around the Sun once every 15 thousand years.

This is how planet X rotates. Scheme from the journal Science
PLUTO KILLER
It is curious that one of the authors of the discovery of the 9th planet, Mike Bryan, ironically used to have the nickname ... "the killer of the 9th planet." The fact is that until 2006, Pluto was considered the ninth planet of the solar system. However, in 2005, Mike Brown discovered Eris, a planet slightly larger than Pluto. And it soon became clear that there are several such celestial bodies in the Kuiper belt. As a result, the International Astronomical Union decided to introduce a third criterion into the definition of the concept of "planet": the planet must clear its orbit from other celestial bodies comparable in scale. As a result, Pluto was demoted to a dwarf planet, and the number of planets in the solar system was reduced to eight. As for Brown, he published a non-fiction book under the eloquent title How I Killed Pluto.
“The most interesting thing is that even then I was convinced that Planet X must exist on the outskirts of the solar system,” recalls Brown. - In 2003, our group discovered the minor planet Sedna. It is slightly smaller than Pluto and Eris in size, but its orbit lies far beyond the Kuiper belt and is not subject to the gravitational influence of Neptune. Sedna was at that time the most distant known large body in the solar system. The question arose, what force forced it to enter such a non-standard orbit? The answer is obvious: only a massive planet the size of Neptune could pull Sedna to such a distant trajectory.
WHO IS KONSTANTIN BATYGIN?
Everything is clear with Mike Brown. He is an authoritative scientist with great experience and an excellent track record. And who is Konstantin Batygin? At the age of 13, he moved with his parents from Russia to the United States. Graduated with honors from Harvard University. Konstantin is not yet 30 years old, but he is already a professor at the California Institute of Technology! They talk about him as a mathematical and computer genius. In their tandem with Mike Brown, calculations and computer simulations are Konstantin's area of ​​responsibility.
However, it is too early to officially talk about the discovery of the 9th planet. You have to see it and fix it. There is now competition among astronomers to be the first scientist to catch Planet X through a telescope. Konstantin Batygin and Mike Brown intend to hold the lead here as well, they have at their disposal a large telescope at the Gemeni Observatory in Hawaii. But they now have many competitors around the world.
AND AT THIS TIME
Stephen Hawking: "It's time to flee the Earth"
Professor Stephen Hawking, one of the most respected scientists in the world, whose statements mankind listens with interest, gave an interview to the British Radio Times Radio. And again he - humanity - frightened, expressing doubt that we will survive the next 100 years. Because we can destroy ourselves by developing science and technology. Most of all, according to the professor, nuclear weapons and genetically modified viruses are now terrible (details)"

Administration 3 comments

Scientists have created a real sensation - found tenth planet in the solar system.

Yes, exactly the tenth! After all, Pluto was considered the ninth planet revolving around the Sun for several generations of scientists. And although he is deprived of the status of the planet, the number nine will remain with him forever.

Astronomers, after much research, finally made sure that outside the Kuiper Belt there is a large celestial body, 10 times more massive than the Earth. And that, most importantly, it accurately moves in a stable orbit, making one revolution around the star in 15 thousand years.

It follows from the report of scientists that the celestial body they discovered moves along an elongated and inclined (relative to the Earth) orbit, and in its parameters it is very similar to gas giants like Uranus or Neptune. In their opinion, Planet X was knocked out of the nascent solar system more than 4 billion years ago, and therefore for a long time it was inaccessible to study. The matter was also complicated by the fact that the orbit of Planet X is very elongated, therefore, in different periods, the distance between it and the Sun ranges from 200 to 1200 astronomical units.

According to the researchers themselves, they managed to discover a new planet by observing the gravitational perturbations that it had on nearby celestial bodies. Now, when it became known exactly where exactly to look for, scientists will be able to properly set up the equipment and observe the planet through a telescope.

However, despite the high degree of reliability of the information received by astronomers, the final confirmation of the existence of this celestial body is likely to take at least five years. And in the event that the existence of Planet X is finally proven, then it will add to the list of planets in the solar system. According to astronomers, the accuracy of the calculations is very high, and the possible error is no more than 0.007 percent.

However, such caution on the part of the official scientific community is quite understandable. The existence of Planet X or Nibiru (as many have already dubbed it) was purely hypothetical for many years, and this name was exploited more by all sorts of hoaxers than by scientists. The former, by the way, are still convinced that an attempt to find out more details about Planet X will entail terrible consequences, such as the traditional end of the world or the enslavement of earthly civilization by hostile aliens. But the scientists themselves hope that if successful, they will be able to discover a lot of useful information and reveal more secrets related to the birth of the solar system.

The universe is full of strange things. Recently, stars have been discovered that travel through the universe at ultra-high speeds. And in space, clouds were found that stretched for several light years, which smell like raspberries or rum. Space is fraught with many amazing and incredible things.

This article will focus on planets that are not quite ordinary in our understanding. We have more or less studied several planets of our solar system, they all have some common features, but also have many differences. And what can we say about planets on other star systems, which can be very different from ours.

These strange and mysterious planets outside the solar system have been discovered within the last decade or so.

Let's take a look at 10 most unusual planets outside the solar system.

#10

HD 209458b located at a distance of 153 light years from Earth in constellation Pegasus. It is estimated to be 30% more than Jupiter, and the diameter of its orbit is 1/8 of the diameter of the orbit Mercury, that's less than 10 million kilometers. Naturally, the temperature of this planet is very high: about 1250°C - 1500°C.

A striking feature of this planet is that this gas giant under the influence of high temperature and enormous pressure, it cannot hold its atmosphere. Various gases in the atmosphere overcome the gravitational field of the planet, accelerating to tremendous speeds.

All this makes HD 209458b a unique planet that has its own tail, consisting of a stream of planetary gases.

And, despite the fact that the evaporation of the planet is very active, it does not particularly affect the planet itself. It would take about a trillion years for the planet to completely evaporate.

#9

Stone Rain Planet (CoRoT-7 b)

It is a very unusual planet outside the solar system. Its distance from Earth is 489 light years. This is a super-Earth with a radius 1.5 times that of the Earth, but with a mass of about 7 times the mass Earth. This is due to the proximity of this planet to its luminary. CoRoT-7. It completes one revolution around the star in 20 Earth hours.

Most likely, before the planet was a gas giant, similar to ours Jupiter or Saturn, but due to the proximity to its star, all the light elements of the planet evaporated, while the heavy ones remained. Thus, it consists mainly of stone.

Due to the proximity of the planet to the star, it is tidally locked, i.e. always faces the star on one side. On the illuminated side, the surface temperature of the planet can reach up to 4000°C, while on the other side the temperature is 3500°C.

This temperature creates conditions for the appearance of an atmosphere consisting of molten stone (magma). Just imagine, the illuminated side of the planet is nothing more than a seething ocean of lava, with a burning atmosphere, which falls on the dark side of the planet like stone rain.