The largest astronomical object in the Kuiper Belt. Journey Through Our Universe: The Kuiper Belt. Comets and the Oort Cloud

Often referred to as the boundary of the solar system. This disk extends at a distance of 30 to 50 AU (1AU=150 million km) from the Sun. Its existence was reliably confirmed not so long ago, and today its study is a new direction in planetary sciences. The Kuiper belt was named after astronomer Gerard Kuiper, who predicted its existence in 1951. It is assumed that most of the Kuiper belt objects in composition are ice with small impurities of organic matter, that is, close to cometary matter.

In 1992, astronomers discovered a reddish speck at a distance of 42 AU. from the Sun - the first recorded object Kuiper belts, or a trans-Neptunian object. Since then, more than a thousand have been discovered.

Kuiper belt objects are divided into three categories. Classical objects have approximately circular orbits with a slight inclination, not associated with the motion of the planets. The most famous minor planets are mainly from among them.

Resonant objects form an orbital resonance with Neptune 1:2, 2:3, 2:5, 3:4, 3:5, 4:5 or 4:7. Objects with a 2:3 resonance are called plutinos, after their brightest representative, Pluto.

Astronomer Gerard Kuiper, after whom the Kuiper belt is named

Scattered objects have a large orbital eccentricity and can be several hundred astronomical units away from the Sun at aphelion. It is believed that such objects once came too close to Neptune, whose gravitational influence stretched their orbits. A prime example of this group is Sedna.

The International Astronomical Union (IAU) has been dealing with the nomenclature of planets and satellites since 1919. The decisions of this organization affect the work of all professional astronomers. However, sometimes the IAU makes recommendations on astronomical issues that excite the entire public. One such recommendation was to reclassify Pluto as a dwarf planet. Now it belongs to the trans-Neptunian objects, and is the second largest and most famous of them.

One of the largest Kuiper belt objects is 2002 LM60, also known as Quaoar or Quaoar. The name Kwaoar comes from the mythology of the Tongva people, who once lived in what is now Los Angeles, and denotes a great creative force.

Quaoar orbits around 42 AU in diameter. with a period of 288 years. It was first photographed back in 1980, but was only listed as a trans-Neptunian body in 2002 by astronomers Mike Brown and his colleagues at the California Institute of Technology (Caltech) in California.

The diameter of Quaoar is about 1250 km, approximately the same as that of Charon, which forms a binary system with Pluto. It has been the largest Kuiper belt object since the discovery of Pluto in 1930 and Charon in 1978. And it is really huge: its volume is approximately equivalent to the total volume of 50,000 asteroids.

Discovered in 2004, 2004 DW, known as Orc, or Orcus (Orcus) turned out to be even larger - 1520 km in diameter. The radius of its orbit is about 45 AU.
Another Kuiper belt object 2005 FY9, tentatively named the Easter Bunny, was discovered on May 31, 2005 by the same team of Mike Brown at the California Institute of Technology (Caltech). Its discovery was announced on July 29, along with the announcement of two more trans-Neptunian objects: 2003 EL61 and 2003 UB313, also known as Eris.

2005 FY9 is the only official name of the object so far. Discovered by the Spitzer space telescope, it still remains a mystery. Its diameter is 50 to 75% that of Pluto.

2003 EL61, as yet unnamed, is about the same size but brighter, making it one of the best-known trans-Neptunian objects.

2003 EL61, like Pluto, has an orbital period of 308 years, but its orbit has a larger eccentricity. Due to the high reflectivity of 2003 EL61, it is the third brightest Kuiper belt object after Pluto and 2005 FY9. It is so bright that sometimes it can even be seen in powerful amateur telescopes, although its mass is only 32% of the mass of Pluto. 2003 EL61 is a type of scattered Kuiper belt object.

Interestingly, 2003 EL61 has two satellites. Although scientists are already calm about the fact that most Kuiper belt objects may turn out to be complex planetary systems.

Eris, ranked first as a planet, and then transferred together with Pluto to the group of trans-Neptunian objects, is today considered a minor planet and is the largest Kuiper belt object.

The diameter of Eris is 2400 kilometers, which is 6% larger than the diameter of Pluto. Its mass was determined thanks to its satellite - tiny Dysnomia, which has a period of revolution of 16 days. It is interesting that at first the discoverers planned to name the dwarf planet and its companion Xena and Gabrielle in honor of the heroines of the famous series.

In March 2004, a team of astronomers announced the discovery of a minor planet orbiting the Sun at a very large distance, where solar radiation is exceptionally low. Mike Brown, in collaboration with Dr. Chad Trujillo of the Gemini Observatory, Hawaii, and Dr. David Rabinowitz of Yale University, discovered it back in 2003. The discovered minor planet was officially named 2003 VB12, but is better known as Sedna, an Eskimo goddess living in the depths of the Arctic Ocean.

Sedna's orbital period is 10,500 years, and its diameter is just over a quarter of Pluto's. Its orbit is elongated, and at its farthest point it is 900 AU from the Sun. (for comparison, the radius of Pluto's orbit is 38 AU). The discoverers of Sedna ranked it among the objects of the inner part of the Oort cloud, since it never approaches the Sun closer than 76 AU. However, Sedna cannot be considered a classical object of the Oort region, since, despite its exceptionally elongated orbit, its movement determines the sun and objects of the solar system, and not random disturbances from outside. Sedna itself is unusual, because it was rather strange to find such a large object in the empty extended space between the Kuiper belt and the Oort cloud. It is possible that the Oort cloud extends further into the solar system than previously thought.

Sedna is now considered to be one of the scattered Kuiper belt objects, which also includes 1995 TL8, 2000 YW134 and 2000 CR105. 2000 CR105, discovered eight years ago, is unique in its exceptionally elongated orbit, the semi-major axis of which is almost 400 AU.

Another feature of Sedna is its reddish tint. Only Mars is redder. And the temperature on the surface of an amazing small planet does not exceed -240 ° C. This is very small and it is impossible to directly measure the heat from the planet (infrared radiation), so data from a variety of available sources is used.

The same is true of the rest of the Kuiper belt objects. Moreover, it is very difficult to measure the diameter of these objects. As a rule, their size is determined by the brightness, depending on the surface area. It is assumed that the albedo of a minor planet is equal to the albedo of comets, that is, about 4%. Although recent data suggests that it could be as high as 12%, that is, Kuiper belt objects could be much smaller than previously thought.

In particular, object 2003 EL61 is of interest because it is too reflective. Approximately in the same orbit, five more similar bodies were discovered. The strange thing is that minor planets are not massive enough to hold an atmosphere that could crystallize and cover the surface.
On December 13, 2005, a minor planet 2004 XR 190, named Buffy, was discovered. Buffy's diameter is about 500-1000 km, which is not a record for minor planets. Another thing is surprising: unlike the scattered objects of the Kuiper belt, which have an elongated orbit, 2004 XR 190 differs in an almost circular orbit (perihelion at a distance of 52 AU from the Sun, aphelion at a distance of 62 AU), inclined at an angle of 47 degrees to the plane of the ecliptic. The reason for the occurrence of such a trajectory is still unclear to astronomers.

Until now, among some astronomers there is an opinion that within the Kuiper belt there is some kind of massive body, no less than Pluto in size. Back in the first half of the last century, scientists predicted the existence of Neptune from the perturbations it exerts on Uranus. Later, the American astronomer Percival Lowell tried to detect a planet beyond Neptune that could distort its trajectory. Indeed, Pluto was discovered in 1930. True, it immediately became clear that its mass is too small (0.002 Earth) to perceptibly perturb the movement of massive Neptune. Therefore, the suspicion remained that the mysterious planet "X" was not Pluto, but a larger minor planet that had not yet been discovered. Subsequently, it turned out that the deviations in the movement of Pluto were only a measurement error.

Of course, theoretically, the planet "X" can exist if it is small and distant enough to have a noticeable effect on the trajectory of Pluto.

But the Kuiper belt object closest to us may be Saturn's moon, Phoebe. It rotates around the planet in the opposite direction, which indicates that Phoebe was not formed in the protoplanetary disk of Saturn, but somewhere else and later was captured by it.

Saturn's moon - Phoebe

Could have formed in a heliocentric orbit near Saturn from the debris that formed its core. According to another possible scenario, Phoebe could have been captured from an area much more distant. For example, from the Kuiper belt. The satellite has a density of 1.6 g/cm3, so it cannot be said whether it is closer to Pluto, which has a density of 1.9 g/cm3, or to Saturnian satellites, whose average density is about 1.3 g/cm3. However, this indicator is too unreliable to rely on it. Therefore, this issue remains highly controversial.

Beyond the Kuiper belt is another more global formation - the Oort cloud. The idea of ​​the existence of such a cloud was first put forward by the Estonian astronomer Ernst Epik in 1932, and then theoretically developed by the Dutch astrophysicist Jan Oort in the 1950s, after whom the cloud was named. It has been suggested that comets come from an extended spherical shell, consisting of icy bodies, on the outskirts of the solar system. This huge swarm of objects is today called the Oort cloud. It extends into a sphere with a radius of 5,000 to 100,000 AU.

Consists of billions of ice bodies. Occasionally, passing stars disrupt the orbit of one of the bodies, causing it to move into the inner solar system like a long-period comet. Such comets have a very large and elongated orbit and, as a rule, are observed only once. One of the examples of long-period comets are comets Halley and Swift-Tuttle (Swift-Tuttle). In contrast, short-period comets with an orbital period of less than 200 years move in the plane of the planets and come to us from the Kuiper belt.

It is believed that the Oort Cloud has the highest density in the plane of the ecliptic, about one-sixth of all objects that make up the Oort cloud are located here. The temperature here is not higher than 4K, which is close to absolute zero. The space behind the Oort cloud no longer belongs to the solar system, as well as the boundary regions of the Oort cloud.

June 1st, 2015

The centuries-old search for the boundaries of the solar system has repeatedly redrawn the harmonious picture of the universe, forcing scientists to offer new hypotheses as to why the Sun has so many satellites and planets. First, astronomers discovered that in addition to the large planets in the solar system, there are thousands of small cosmic bodies. They form an asteroid belt located inside the orbit of Jupiter. Then Pluto, Sedna, Ork, Kvaoar, Varuna and many other objects were discovered that revolve around the Sun at distances tens and hundreds of times greater than Jupiter. The so-called Kuiper belt, in which the above-mentioned celestial bodies are located, discovered at the end of the 20th century, destroyed the prevailing system of views, as a result, a number of astronomers even proposed depriving Pluto of the status of a planet. Remember, recently we discussed a dispute about

Let's remember the history of these discoveries ...

Planets are celestial bodies that revolve around the Sun, have sufficient weight and size, are spherical in shape, and are able to clear their orbit from small cosmic bodies. In 2006, members of the International Astronomical Union decided that there were eight planets in the solar system: Venus, Mercury, Earth, Jupiter, Mars, Saturn, Neptune and Uranus.

In contrast to this concept, there is the term "dwarf planet", which is understood as a celestial body that also revolves around the Sun, has the weight and shape in order to take the form of a ball, but is not able to clear its orbit and is not a satellite.

Scientists, after research, came to the conclusion that in ancient times, in the early stages of the existence of the solar system, there were dwarf planets in it. The first objects of the system were formed a little over 4.5 billion years ago from a gas and dust cloud. Then, for the first three million years, small objects revolved around the Sun, colliding with each other and collapsing. The remains of these objects today are presented in the form of ancient asteroids.

An international team of research scientists, using an ultra-sensitive magnetometer, studied samples of ancient meteorites. Scientists have established the origin of the magnetic field of these objects: as it turned out, it arose as a result of magnetization in a more powerful field. From all this, we can conclude that the first bodies of the solar system, under the outer shell, had a metal hot core, because it is the liquid metal in motion that creates the magnetic field of the planet.

The first objects in diameter reached about 160 kilometers. Thus, in order to create a magnetic field sufficient to magnetize the minerals of the outer layer, the metal had to move fast enough. That is, it turns out that the ancient planets of the solar system were much more like modern planets than previously thought.

In addition to Pluto, there are many more small dwarf planets in the solar system, which are called asteroids, or minor planets.

The largest of these small planets, Ceres, is 770 kilometers in diameter. In size, it is smaller than the Moon by the same amount as the Moon is smaller than the planet Earth.

Ceres was discovered on January 1, 1801. Italian astronomer Giuseppe Piazzi discovered a star that was behaving strangely. In the course of research, he discovered that this star moves slowly in relation to other stars. The astronomer came to the conclusion that he had discovered a new planet. A little later, the German astronomer and mathematician Karl Gauss calculated the orbit of Ceres. It turned out that it is located between the orbits of Jupiter and Mars, just in the place where another planet should have been. Of course, it was a big victory, because scientists finally managed to find the long-predicted planet.

A year later, in 1802, scientists were even more surprised when, at about the same place, the German astronomer Heinrich Olbers discovered the planet Pallas. Two years later, another planet was discovered - Juno, and in 1807 - Vesta. Then, for forty years, scientists failed to find new space objects, and only in 1845 the planet Astrea was discovered, and in 1847 - Hebe, Irida and Flora. By the end of the century, scientists had discovered about four hundred minor planets.

In 1920, scientists discovered the asteroid Hidalgo, which moves through the orbit of Jupiter and passes relatively close to the orbit of Saturn. This asteroid is also notable for the fact that it is the only known planet to have a very elongated orbit, which is inclined to the plane of the Earth's orbit at an angle of 43 degrees. This minor planet was named after the famous hero of the Mexican Revolution, Hidalgo y Castilla, who died in 1811.

In 1936, the zone of dwarf planets was replenished with new objects. Then the asteroid Adonis was discovered. The peculiarity of this minor planet was that it moves away from the Sun at the most distant point at the distance of Jupiter, and at the closest point it approaches the orbit of Mercury.

In 1949, Icarus was also discovered, a minor planet that is removed from the Sun at its maximum point by a distance equal to two radii of the earth's orbit. The minimum distance of the planet is equal to one fifth of the distance from our planet to the Sun. It is noteworthy that none of the known planets approaches the Sun at such a close distance. As a matter of fact, hence the name (remember the legend of Icarus).

According to scientists, there are currently about 40-50 thousand small planets in the solar system. But of all this multitude, only a small part can be explored with the help of astronomical instruments.

If we talk about the size of small planets, then they are quite diverse. There are few planets approximately equal in size to Pallas or Ceres (they reach about 490 kilometers in diameter). Approximately seventy planets have a diameter of about 100 kilometers. Most dwarfs are 20-40 kilometers across, but there are some that are about 2-3 kilometers in diameter. Despite the fact that far from all asteroids have been discovered and studied, it is already possible to say that their total mass is approximately one thousandth of the mass of the Earth. But this is only for now, because, according to scientists, no more than five percent of the total number of asteroids that are available for research with modern equipment has been discovered at present.

Of course, it can be assumed that the physical features of asteroids are about the same, but in fact, scientists are faced with a wide variety. In particular, during the study of the reflectivity of asteroids, it was found that Pallas and Ceres reflect light like terrestrial rocks, Juno like light rocks, and Vesta reflects light like white clouds. This is very interesting, because asteroids are so small that they are not able to keep the atmosphere around them. Thus, asteroids are devoid of an atmosphere and the reflectivity depends directly on the materials that make up the surface of these planets. And yet - in some cases, there is a fluctuation in brightness, which may indicate that these planets have an irregular shape and rotate around their axis.

By the end of the last century, astronomers had discovered about 20 thousand small planets or asteroids. In total, astronomers read, there are about a million asteroids in space, the size of which exceeds one kilometer, and which may be of interest to science.

Three types of planets

The great planetographic discovery - the discovery of the outer asteroid belt located beyond the orbit of Neptune - significantly changed the idea of ​​​​the solar system. On the scale of our planet, such an event would correspond to the discovery of a previously unknown continent. There was a new look at the structure of the planetary system, which until then seemed not quite harmonious, since it had a "strange" planet - the most distant, ninth in a row from the Sun - Pluto. It did not fit into the regular alternation of the eight previous planets. The four planets closest to the Sun (Mercury, Venus, Earth and Mars) belong to the so-called terrestrial type - they are relatively small, but “heavy”, composed mainly of rocks, and some even have an iron core. The next four planets (Jupiter, Saturn, Uranus and Neptune) are called giant planets - they are very large, several times larger than the Earth, and "light", consisting mainly of gases. Even further away is Pluto, not like the planets of the first and second groups. It is much smaller than the Moon and consists mainly of ice. Pluto also differs in the nature of its movement: if the first eight planets move around the Sun in almost circular orbits located in the same plane, then this planet's orbit is very elongated and strongly inclined.

So Pluto would have been an "outcast" of the solar system, if in the last five years it had not picked up a worthy company: a completely new, third, type of planetary bodies - icy planetoids. As a result, he became just one of the objects of the outer asteroid belt. Thus, the inner, or main, asteroid belt, located between Mars and Jupiter, ceased to be a unique formation and it had an “ice brother”, the so-called Kuiper belt. This structure of the solar system is in good agreement with modern ideas about the formation of planets from a protoplanetary cloud of matter. In the hottest region near the Sun, refractory materials remained - metals and rocks, from which terrestrial planets were formed. The gases escaped to a cooler, more distant region, where they condensed into giant planets. Part of the gases that were at the very edge, in the coldest region, turned into ice, forming many tiny planetoids, since there was little substance on the outskirts of the protoplanetary cloud. In addition to the planets, comets were formed from this cloud, whose trajectories penetrate all three regions, as well as satellites circling the planets, cosmic dust and small stones - fragments of asteroids plowing the airless space and sometimes falling to Earth in the form of meteorites.

ice belt

In 1930, when Pluto was discovered, the orbit of this planet began to be considered the boundary of the solar system, since only vagrant comets fly beyond it. It was believed that Pluto carries out his frontier service all alone. So they thought until 1992, when the asteroid 1992 QB1 was discovered beyond the orbit of Pluto, but not too far from it. This event was the beginning of subsequent discoveries. The creation of new powerful telescopes on Earth and the launch of several space telescopes contributed to the identification of many small objects on the outskirts of the solar system that could not be seen before. The "impact five-year plan" was the period from 1999 to 2003, during which about 800 previously unknown asteroids were discovered. It became obvious that Pluto has a huge family, consisting of thousands of small celestial bodies.

The outer asteroid belt, located beyond the orbit of Neptune, is most often called the Kuiper belt in honor of the American astronomer Gerard Peter Kuiper (1905-1973), who explored the Moon and the planets of the solar system. However, the assignment of his name to the outer asteroid belt looks very strange. The fact is that Kuiper just believed that all small planets, if any, were ever near the orbit of Pluto, should have shifted to very distant regions, and the space immediately adjacent to Pluto was free from cosmic bodies. As for the assumption of the existence of numerous small icy asteroids beyond the orbit of Neptune (indistinguishable in telescopes of that time), it was repeatedly expressed from 1930 to 1980 by other astronomers - the Americans Leonard and Whipple, the Irishman Edgeworth, the Uruguayan Fernandez. Nevertheless, the name of Kuiper, who denied the very possibility of its existence, was somehow firmly "glued" to this asteroid belt. The International Astronomical Union recommends calling outer belt asteroids simply trans-Neptunian objects, that is, located beyond the orbit of the eighth planet, Neptune. This designation corresponds to the geography of the solar system and is in no way connected with any scientific hypotheses of past years.

Kuiper inhabitants

About 1,000 Kuiper belt asteroids are now known, most of which are several hundred kilometers across, with the ten largest having diameters in excess of 1,000 kilometers. Nevertheless, the total mass of these bodies is small - if you “blind” one ball out of them, then it will be equal in volume to 2/3 of the Moon. Small satellites revolve around 14 asteroids. It is believed that there are about 500,000 asteroids larger than 30 km in total in the Kuiper belt. In area, the Kuiper belt is one and a half times larger than that part of the solar system around which it is located, that is, limited by the orbit of Neptune. It is not yet known what the asteroids in the Kuiper belt are made of, but it is clear that various types of ice (water, nitrogen, methane, ammonia, methanol - alcohol, carbon dioxide - "dry ice", etc.) should play the main role in their structure, since the temperature in this extremely remote region from the Sun is very low. In such a natural “freezer”, the substance from which the planets of the solar system were formed in the distant past could be preserved unchanged.

More than 90% of new objects move in almost circular "classical" orbits located at distances from 30 to 50 astronomical units from the Sun. Many of the orbits are strongly inclined to the plane of the solar system, in 20 asteroids the inclination exceeds 40°, and in some it even reaches 90°. Therefore, the outlines of the Kuiper belt look like a thick donut, within which thousands of small celestial bodies move. The outer boundary of the belt at a distance of 47 AU. e. from the Sun is expressed very sharply, so there was an assumption about the presence of a rather large planetary object there, perhaps even the size of Mars (that is, half the size of the Earth), whose gravitational effect does not allow asteroids to “disperse”. The search for this hypothetical planet is now underway. However, the outer boundary of the belt does not serve as an insurmountable barrier, and 43 asteroids (4% of their known number) go beyond its limits into a region of almost absolute cold and darkness, following highly elongated orbits extending over distances of more than 100 astronomical units (15 billion km ) from the sun.

Year after year, the idea of ​​Pluto's role in the solar system has changed, and now it is considered as the leader of the icy Kuiper belt dwarf planets. A group of two hundred asteroids, in which both the location of the orbits and the speed of movement practically coincide with the same characteristics of Pluto, were even singled out in a special family called "plutinos", that is, "plutons".

The outer edge of the Kuiper Belt, sharply defined at 47 AU from the Sun, could well be called the new boundary of the solar system. However, some of the icy asteroids are removed beyond this limit. In addition, there is a magnetic field around the Sun that extends up to about 100 AU. e. This area is called the heliosphere - the sphere of the Sun's magnetic field.

Dwarf planet or giant asteroid?

Since 1992, the number of asteroids discovered on the outskirts of the solar system has increased and it has gradually become clearer that Pluto is not an independent planet, but only the largest representative of the outer asteroid belt. Thunder struck in 1999, when it was proposed to assign a serial number to Pluto, which each asteroid has. There was also a suitable reason - the number of numbered objects was approaching ten thousand, so they wanted to transfer Pluto from planets to asteroids with honor, assigning it a "remarkable" number of 10,000. The discussion flared up immediately - some astronomers were in favor of this proposal, others strongly opposed. As a result, Pluto was left alone for a while, and the “honorary” number went to the next ordinary asteroid. However, in 2005, discussion of Pluto's status flared up with renewed vigor. Oil was added to the fire by the discovery by Michael Brown's group at the Palomar Observatory in the USA of another asteroid in the Kuiper belt. This object, which was given the designation 2003 UB313, turned out to be not ordinary, but rather large. It is now considered most likely that the new object has a diameter of 2,800 km, while Pluto is 2,390 km. However, the data on the new asteroid has yet to be refined in more reliable ways. For example, wait until it passes against the background of a distant star and obscures its light. From the time between the disappearance and the appearance of a star, it will be possible to determine the diameter of the asteroid very accurately. True, such astronomical events rarely happen, and it remains only to wait for the right moment.

The discoverers said that if a new asteroid is larger than the planet Pluto, then it should also be considered a planet. At the same time, they said that if Pluto had been discovered not in 1930, but now, then the question of its classification would not even have arisen - it would certainly have been classified as an asteroid. However, history is history, and Pluto's belonging to the planets has become not so much an astronomical as a general cultural phenomenon, so the question of transferring Pluto to asteroids is met with quite strong resistance.

A new large object had to be given its own name, and here the discoverers had a serious difficulty. If it is a planet, then according to the rules of the International Astronomical Union (IAU) and in accordance with tradition, it should receive the name of a deity from classical Greco-Roman mythology, and if it is an asteroid, then it should be named after a mythological character associated with the underworld ruled by Pluto . True, Brown's group found a witty way out of this situation by proposing to name the new "giant asteroid" Persephone - the name of Pluto's wife in Greek mythology. This name fits all the rules. But here an obstacle of a purely bureaucratic nature arose: the planets are managed by one working group of the IAU, and the asteroids by another. The dispute reached such a pitch that a special committee of 19 astronomers from different countries was formed to decide whether the object 2003 UB313 should be considered a planet.

The members of this committee have been unable to come to a consensus for several months now. In the end, the desperate chairman, the British astronomer Ivan Williams (who claims, by the way, that his name is typically Welsh, characteristic of a native of Wales), found an easy way out of the deadlock by stating that if an agreed conclusion could not be reached soon, then he will not follow a scientific path, but will hold the most ordinary vote, and the issue will be decided by a simple majority of votes.

The most distant planetoid

The new idea that Pluto belongs not so much to planets as to asteroids has not yet had time to settle down, but has already found many adherents. It seemed that harmony was found in the arrangement of the planets, which is not hindered by the presence of an "extra" ninth planet. However, the discoveries of new planetoids continued and on March 15, 2004 they led to another violation of harmony among the planets. On this day, a group of American astronomers, led by Michael Brown, announced that during observations at the high-altitude Palomar Observatory (California) in November 2003, they had discovered the most distant object in the solar system. It turned out to be located 90 times farther from the Sun than the Earth, and 3 times farther than the "most distant" planet Pluto. And such a gigantic removal turned out to be only the part of its orbit closest to the Sun. The diameter of this asteroid is smaller than that of Pluto - about 1,500 km. It was named Sedna after the name of the sea mermaid, the ruler of the cold and dark depths of the northern seas in the myths of the Eskimos (Inuit). Such a character was not chosen by chance - after all, this planetoid “dives” into the darkest and coldest region of the solar system, moving away from the Sun 928 times farther than the Earth, and 19 times farther than Pluto. None of the known asteroids goes that far. Sedna immediately took the place of the "rogue planet" that previously belonged to Pluto. Its highly elongated orbit again violated established ideas about the solar system.

It makes one revolution around the Sun in a monstrous period - 10,500 years! This planetoid is no longer considered to be part of the Kuiper belt, since even at its closest approach, Sedna is 1.5 times farther from the Sun than the outer boundary of this belt. The asteroid has become a kind of "Pluto of the XXI century" - an object whose role is incomprehensible. It is constantly in complete darkness, and the Sun looks like a small star from its surface. It is eternally cold. At the same time, the planetoid turned out to be colored in a rather intense red color and is inferior in “redness” only to Mars. It is not clear whether Sedna is alone or if there are other planetoids at such a great distance - after all, the capabilities of telescopes make it possible to detect an object with a similar orbit only during 1% of its revolution around the Sun, when it is in the closest part of its trajectory. For Sedna, such a period lasts about 100 years, and then it goes to a distant region for more than 10,000 years, and there it is impossible to see an object of its size in modern telescopes.

AND . Remember also what it is The original article is on the website InfoGlaz.rf Link to the article from which this copy is made -