Solar System (Solar System) is based on the sun as the center, and all bound by the solar gravitational objects aggregates: eight planets, at least 165 known satellites, three have been identified by the short planets (Pluto and his satellite) and hundreds of millions of small solar system bodies. These small objects, including asteroids, Kuiper Belt objects, comets and interstellar dust.

A broad sense, the field of solar system including the sun, four inner planets like the Earth, composed by many small rocky asteroid belt, four gas filled the huge extrasolar planets, full of frozen small rocks, known as the Kuiper Belt’s second small celestial area. Kuiper Belt in addition to discrete disk ecliptic, the sun circle and still hypothetical Oort cloud.

In accordance with the distance to the sun, planetary order are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune, 8 in 6 have natural satellites around these stars are accustomed to because the Earth’s satellite is called are considered to be the moon and the moon. In the outer planets are much by the dust and small particles consisting of ring around the planet, and apart from the Earth, the planets visible to the naked eye in the name of the Five Elements in the West are all in Greek and Roman myths of gods name. Are three dwarf planets: Pluto, Kuiper Belt, one of the largest celestial bodies; Ceres, the largest asteroid belt objects; and are Ecliptic discrete objects shenxing quarrel.

The solar system are among the leading centers of the sun, it is classified as a G2V spectra of main sequence stars, with the quality of the solar system known to 99.86%, and gravity dominate the solar system. Jupiter and Saturn, our solar system are the two biggest planets, but also the quality of accounting for the remaining 90%, the current hypothesis is still in the Oort cloud, do not know what percentage will the quality of possession.

The main objects of our solar system orbit around the sun in the earth’s revolution orbit plane (the ecliptic) in the vicinity. Planets are very close to the ecliptic, while comets and Kuiper Belt Objects, there is usually more obvious angle.

Bird’s-eye view from the north down the solar system, all the planets and the vast majority of other celestial bodies, are anti-clockwise (dextral) direction around the sun. Some exceptions, such as Halley’s Comet.

Sports of the sun around the celestial bodies have to comply with the law of planetary motion Kepler, orbit the sun are a focal point for the ellipse, and the more close to the sun at the time of the faster. Nearly circular orbit of the planet, but many comets, asteroids and Kuiper Belt objects orbit is highly elliptical.

In such a vast space, there are many ways to show each of the solar system orbit the distance. In fact, the farther from the Sun clitellum of the planets or with the previous one will be farther away, and only a few exceptions. For example, Venus in the Mercury about 0.33 astronomical units outside the distance, but the distance between Saturn and Jupiter are 4.3 astronomical units, Neptune in Uranus 10.5 astronomical units apart. Have some relationship attempt to explain these changes in distance between the orbit interaction, but this theory has never been confirmed.

It is believed that the formation of the solar system should be based on nebula hypothesis, the earliest in 1755 by Kant and Laplace in 1796 by a separate proposed. Consider this theory are in the solar system 4.6 billion years ago in a huge collapse of molecular cloud formed. This nebula was originally the size of several light-years, and at the same time the birth of a few stars. Research dating back to ancient meteorite elements revealed that only the heart of a supernova explosion can produce some of these elements, so the cluster that contains the sun is bound in the vicinity of supernova debris. May come from supernova explosion shock wave near the neighboring solar nebula density, making gravity to overcome internal gas pressure caused by the expansion of collapse, which triggered the birth of the sun.

Been identified as areas of the original solar nebula that formed the solar system will be the region diameter is estimated at 7-2000 astronomical units, and the quality of only a little more than the sun (many from 0.1 to 0.001 solar masses). When the nebula began to collapse when the law of conservation of angular momentum to accelerate its speed, the internal atomic collision frequency increase. Its central region to focus the bulk of the mass, temperature than the surrounding disk is more hot. When gravity, gas pressure, magnetic field and rotation of the role in contraction of the nebula, it began to become flat become the original planetary disk rotation, while the diameter of about 200 astronomical units, and in the center has a hot and dense protostar.

Of young stars Jinniu T research, and trust the quality of pre-fusion stage of development is very similar to the sun, appear in the formative stages often have the original planetary disk material associated with. These disks can be extended to several hundred astronomical units, and the hottest part of K can reach thousands of high temperature.

一亿年after the collapse of the nebula center, pressure and density will be large enough to enable the original beginning of the solar hot hydrogen fusion, which would have been increased until hydrostatic balance, so that thermal energy sufficient to resist gravitational contraction can. At this time the sun has become a real star.

Trust by the role of accretion, a wide range of planets from a cloud (solar nebula) in the remaining gas and dust in the birth of:

When the dust particles are still surrounded by the Center’s original star, the planet has already begun to grow;

And through direct contacts, gathered into a 1-10 km diameter of the cluster;

Followed by the formation of larger individual collisions become the diameter of 5 kilometers around the Xingzi;

Medium millions of years in the future through further collisions with the annual speed of 15 centimeters continue to grow.

In the inner solar system, because the excessive warmth of the water and methane volatile elements that should not rally, so the formation of relative Xingzi relatively small (only the quality of the disc has 0.6 percent), and the main ingredients are the melting point higher, such as silicate and metal compounds. Finally these stone objects became terrestrial planets. Again the Xingzi further by the gravitational influence of Jupiter, the original should not be a planet together, and to become what we are seeing now the asteroid belt.

In the longer distances, in the freeze line, the volatile material also can be frozen into a solid, formed Jupiter and Saturn these enormous gas superstar. Uranus and Neptune obtained less material, and because the core was considered mainly ice (hydride) and therefore known as the Ice Fest.

Once the young sun started to produce energy, the solar wind will be the original planetary disk material blown interplanetary space, thus putting an end to the growth of planets. Young T Tauri stars of stellar wind than in the stable stage of much older stars.

According to astronomers speculate that the current solar system will be maintained until the sun left the main sequence. Because the sun is the use of its internal hydrogen as fuel, in order to be able to use the remaining fuel, the sun will become more and more hot, so the burning speed is getting faster and faster. This leads to the sun constantly changing light, changing the speed of light around 11 million years for each Zengliang 10%.

From now around 76 million years later, the sun’s core will be hot enough to make the outer layer of hydrogen fusion happen, this would lead to expansion to the present radius of the sun 260 times, into a red giant. At this point, because of the expansion of volume and surface area, the sun’s total luminosity, but the surface temperature drop per unit area of the photometric dimming.

Subsequently, the sun’s outer deviation was finally exposed core becomes a white dwarf, an extremely dense celestial bodies, only the size of the Earth has a half of the original quality of the sun.

1. The sun (Sun)

The sun is the solar system, the parent stars, but also the most important and most important members. It has enough quality to allow the internal pressure and density sufficient to inhibit and to bear the tremendous energy generated by nuclear fusion, and radiation patterns, such as visible light, so that a stable energy into space.

[Sun in the HR diagram location]

Sun in the HR diagram position

The sun is in the classification of a medium-sized yellow dwarf stars, but such a name very easily misunderstood, in fact, in our galaxy, the sun is a large and bright. HR diagram of stars are based on surface temperature and brightness corresponding to the classification of relations. Typically, temperatures are high will be relatively bright star, and follow this one will be the law of the star is located in the so-called main-sequence band, the sun on the central belt. However, than the sun but the large and bright stars are not many, and the relatively bleak and cold a lot of stars are.

The sun in the stage of stellar evolution are in their prime period, have not been exhausted in the core for nuclear fusion of hydrogen. The brightness of the sun will still be growing, early brightness is only 75 percent now.

Calculation of the solar interior the proportion of hydrogen and helium that the sun has completed half of the life cycle in about 50 million years later, the sun will leave the main sequence band, and become bigger and brighter, but the surface temperature is lower red giant, By then, it will be the brightness of the current thousands of times.

The Sun is a relatively late stage in the evolution of the universe was born of the first group of stars sing, sing it than the second group of stars have more than hydrogen and helium heavy metals (which are astronomical to say: atomic number greater than helium are metal. ). Than hydrogen and helium heavier elements are formed in the stellar core, and must be made through a supernova explosion can be released into the universe of space. In other words, the first generation of stars after the death of the universe have these heavy elements. The oldest stars, only a small amount of metal, then they will have more of the birth of metal. High metal content is considered the development of solar energy are the key to the planetary system, because the planets are from the accumulation of metals formed.

Interplanetary material

In addition to light, the sun has been the emitted electron flow (plasma), that is, the so-called solar wind. The particles flow rate of 1.5 million kilometers per hour, in the solar system to create a thin atmosphere (the solar circle), the scope of at least 100 astronomical units (day ball layer top), and that is our recognition of interplanetary material. The sun’s sunspot cycle (11 years) and frequent flares, coronal mass ejections in the solar circle disruption, resulting in climate space. Accompanied by the sun’s rotation and the rotation of the magnetic field line in the interstellar matter arising from the current sheet, circle the sun, the solar system are the largest structures.

The Earth’s magnetic field from the solar wind interaction with the protection of the Earth’s atmosphere. Mercury and Venus do not have magnetic field, solar wind so that they gradually lose the atmosphere to space. Solar wind and Earth’s magnetic field interactions produced by Aurora, you can close to the Earth’s magnetic pole (such as the Antarctic and the Arctic) to see nearby.

Cosmic rays are from outside the solar system, solar circle barrier of the solar system, the planet’s magnetic field as well as the planet itself provides some protection. Cosmic rays with interstellar matter in the density and intensity of the solar magnetic field cycle changes, so cosmic ray changes in the solar system within the range of what is still unknown.

Interplanetary material, at least in the region in two discoid accumulation of cosmic dust. The first region ecliptic dust clouds are located within the solar system, and are the cause of yellow light. They may be within the asteroid belt objects and planetary impact generated by each other. The second region extending around 10-40 astronomical units in the framework may be within the Kuiper Belt objects similar to each other in the resulting crash.

2. Within the solar system

Traditionally within the solar system are terrestrial planets and the asteroid belt region name, mainly composed of silicates and metals. Crowded in the region close to the sun in the framework of the radius of Jupiter and Saturn than the distance between the shorter.

Within the planetary

[All within a planet]

With all of the planets

Within the planet or four terrestrial planets are characterized by high density, by the rock composition, only a few or no satellites, no-loop system. They are high melting point of minerals, such as the type of silicate minerals, the composition of the surface of the earth’s crust of solid and semi-liquid mantle, as well as by the iron, nickel constitute the core of which consists of metal. 3 of 4 (Venus, Earth, and Mars) have substantial atmosphere, all have impact craters and tectonic surface features (graben and volcanic, etc.). Within the planet easier and closer to the sun than the Earth inside the planets (Mercury and Venus) confusion. Planet is running in a plane, moving in one direction

Mercury

Mercury (Mercury) (0.4 astronomical units) are closest to the sun, is the smallest planet (earth quality 0.055). It has no natural satellites, only known geological features besides impact craters, only perhaps in the early history and are generated during contraction of the fold ridges. Mercury, including the solar wind bombardment of the gas atoms, and only negligible atmospheric. Is still quite unable to explain relatively enormous iron core and a thin mantle. Hypothesis include the enormous impact of spin-off its shell, there are young solar period inhibited shell growth.

Venus

Venus (Venus) (0.7 astronomical units) size and the size of the Earth is similar to (0.86 quality of the Earth), also the same as the Earth has a thick silicate mantle surrounding the core, there is a strong atmosphere and evidence of internal geological activity. However, it is the atmospheric density than the Earth 90 times high and very dry, there is no natural satellites. It is the hot stars of the planets, the surface temperature exceeds 400 ° C, most likely has a lot of the atmosphere caused by greenhouse gases. There is no specific evidence to show that the geological activities Venus is still in progress, but no magnetic field to protect the atmosphere should be depleted, so that the Venusian atmosphere by the volcanic eruption was added.

Earth

The Earth (Earth) (1 astronomical unit) is the largest planet within the highest density and is the only geological activity is still ongoing and has planets life. It also has a unique terrestrial planets in the hydrosphere and the plate was observed in the structure. Also in the Earth’s atmosphere is totally different from other planets, was here the biological survival into freedom containing 21% oxygen. It is only a satellite, that is the moon; lunar terrestrial planets is the only large satellite. The Earth revolution (the Sun) around about 365 days, the rotation of a circle about 1 day. (The sun is not always direct the equator, because the Earth rotates around the sun, somewhat tilted.)

Mars

Mars (Mars) (1.5 astronomical units) than the Earth and Venus small (0.17 quality of the Earth), only to carbon dioxide-based thin atmosphere, its surface, such as the Mount Olympus-intensive and has enormous volcanoes, canyons No. sailors have deep graben, showing the recent geological activity is still intense. Mars has two natural small satellites, David Moss and Faubus, may be captured asteroids.

Asteroid belt

[The main asteroid belt and Trojan asteroids]

The main asteroid belt and Trojan asteroids

Asteroids are small celestial bodies in the solar system the most important members, mainly from rocks and easy composition of volatile substances.

The main asteroid belt located between Mars and Jupiter orbit from the sun from 2.3 to 3.3 astronomical units, which are considered to be in the process of the formation of the solar system by gravitational perturbations of Jupiter and the residual material can not polymerization.

Asteroids scale up to several hundred kilometers from the big and small to have a micron. The biggest apart from Ceres, all the asteroids have been classified as small solar system bodies, but has several asteroids, such as Vesta, Kin-sing of God, if to be confirmed has reached hydrostatic balance may will be re-classified as a dwarf planet.

Asteroid belt have the tens of thousands of stars, possibly up to a number of one million, more than one kilometer in diameter, a small celestial body. Nevertheless, the asteroid belt’s total mass is still not achieve the quality of the thousandth of the Earth. Members of the main asteroid belt are still thinly, and therefore has yet to spacecraft in the crossing when the accident happened.

In diameter, 10 to 10-4 m in small bodies called meteoroids.

Ceres

Ceres (Ceres) (2.77 astronomical unit) is the largest main belt objects, is also short with the only planet. Its close to 1000 kilometers in diameter, so its own gravity is sufficient to make it a ball. In the early 19th century it was found was considered a planet, in the 1850s because there are more small objects were found was re-classified as an asteroid; in 2006, again re-classified as a dwarf planet.

Asteroid family

In the main asteroid belt can be divided into elements based on the track of a few asteroids and asteroids ethnic group. Asteroid satellites are larger asteroids around the operation of small celestial bodies, their identification as a satellite around the planet as clear, because some satellites have been around almost as big as the mother.

In the main belt comets have also, they may be the main source of the Earth in Sheung Shui.

Trojan asteroids located in Jupiter’s L4 or L5 points (in the front and rear planetary orbits unstable gravitational equilibrium point), but “Troy” is also used in other planetary or satellite orbit is located in rugby Long Point on the day of small celestial bodies. Tatsu ethnic Greek ears are 2:3 orbital resonance with Jupiter cycle of the asteroid family, when Jupiter around the sun, when the second lap, this asteroid will be around the sun three times.

Within the solar system also contains many “naughty” asteroid and dust particles, many of which will pass through within the planet’s orbit.

3. In the Solar System

The central region of the solar system are gas planets like superstars and their small-scale satellite homes, and many short-period comets, including the Centaur group is also the region. This area there is no traditional name, and occasionally will be classified as “outside the solar system”, while the outer solar system beyond Neptune is often used to describe the region. Solid in the region, the main components are “ice” (water, ammonia and methane), different to the rock-oriented within the solar system.

Extrasolar planets

[All of the extrasolar planets]

All of the extrasolar planets

In the four outer planets, also known as the Jovian planets around the sun cover 99% of known quality. Jupiter and Saturn’s atmosphere has a lot of hydrogen and helium, Uranus and Neptune’s atmosphere is more “ice”, such as water, ammonia and methane. Some astronomers think they are in the category known as “Uranus ethnic” or “ice superstar.” This star has a planet four gas ring, but only Saturn’s ring can be easily observed from the Earth. “Extrasolar planets” is easy with the “outer planets” confusion, the latter refers to the actual outside of the planets orbit the Earth, but also have extrasolar planets except Mars.

Jupiter

Jupiter (Jupiter) (5.2 astronomical units), mainly composed of hydrogen and helium, and quality is 318 times that of the Earth, but also the quality of other planets combined 2.5 times. Rich internal heat of Jupiter’s atmosphere in its approximate cause some permanent features, such as the cloud band and the Great Red Spot. Jupiter has been found to have 63 satellites, the largest 4, Gan, Callisto, and Europa, show similar characteristics of terrestrial planets, such as volcanism and internal heat. Gambari also Niemi Derby Mercury, and is the largest satellite in the solar system.

Saturn

Saturn (Saturn) (9.5 astronomical units), because the ring system has obvious and well-known, it is very similar to Jupiter, for example, the structure of the atmosphere. Saturn is not very big, only the quality of the Earth 95 times, it has 60 known satellites, Titan and all Adams, with enormous ice volcano, showing signs of geological activity. Mercury Titan than large, and the solar system are the only actual possession of the satellite’s atmosphere.

Uranus

Uranus (Uranus) (19.6 astronomical units), are the lightest extrasolar planets, the quality of the Earth 14 times. Its ecliptic inclination of 90 degrees, so are horizontal lying around the sun, in a very unique planet. Superstar in the gas, it’s the core temperature of the lowest, only very little heat radiation into the space. Known Uranus has 27 satellites, the largest few are Titania,Earl Lane, Ariel, and Miranda.

Neptune

Neptune (Neptune) (30 astronomical units) Although it looks smaller than Uranus, but still higher density so that the quality of the Earth 17 times. Although the radiation out of him more calories, but nowhere near as many of Jupiter and Saturn. Neptune has 13 known satellites, the largest Dayton Choi still active geological activity, with eruption of the geyser in liquid nitrogen, it is the only solar system’s largest retrograde satellite. In the orbit of Neptune has some of 1:1 orbital resonance of the asteroid, composed of Neptune Trojan group.

Comet

Comet attributable to small solar system bodies, usually only a few kilometers in diameter, mainly by the composition of volatile ice. Their orbits with high eccentricity, perihelion general planetary orbits, including the inside, and well beyond the day in the Pluto. When a comet into the inner solar system, after the close and the sun will lead to the cold surface of her material sublimation and ionization, resulting in coma hair and dragged out of gas and dust composition, the naked eye can see the tail of a comet.

Short-period comets orbit cycles are shorter than 200 years of comets, long-period comets orbit cycle may be as long as several thousand years. Short-period comets, like Halley’s Comet, is considered from the Kuiper Belt; long-period comets, like the comet海尔波普, were considered originated in the Oort cloud. There are many groups of comets, such as the Cruz family comets, might have been due to a collapse of the mother. Some of the comet has a hyperbolic orbit, it may come from outside the solar system, but precise measurement of these are very difficult to track. Volatile substances to disperse the hot sun, often after the comet will be classified as an asteroid.

Centaur group

Centaur groups are scattered in the 9-30 range of astronomical units, that is in orbit between Jupiter and Neptune, similar to ice-dominated comet objects. Group of the largest known Centaur objects are 10199 Chariklo, diameter 200-250 km. The first was found is 2060 Chiron, because when close to the sun as the comet-like coma have hair, has now been classified as a comet. Some astronomers would be classified as a Centaur family of discrete internal Kuiper Belt objects, which are regarded as a continuation of the external discrete plate.

4. Outside the Neptune Area

Outside in the Neptune region, often referred to as the outer solar system or outside the Neptune area, still are not the vast number of space exploration. This region seems to be the world’s small solar system bodies (maximum diameter of less than one-fifth of the Earth, the quality is far less than the moon), mainly composed of rock and ice.

Kuiper Belt

Kuiper Belt, the original form, was considered by an asteroid the size of similar, but is mainly composed of debris from the ice with debris consisting of ring, the proliferation of the sun at a distance of 30-50 of the astronomical unit. The region is considered short-period comets – such as Halley’s Comet – the source. It is mainly composed by small solar system bodies, but much the largest Kuiper Belt objects, such as a sing of God, Varuna, 2003 EL61, 2005 FY9 and Eritrea ear blight Adams and so on, may all be classified as dwarf planets. Kuiper Belt is estimated that more than 50 kilometers in diameter-day experience of more than 100,000, but the total mass of the Earth may be only the quality of even only one-tenth of 1 percent. Many Kuiper Belt objects have two or more satellites, and most of the track not in the ecliptic plane.

Kuiper Belt in general can be divided into the resonance zone and with the traditional two parts, the resonance with Neptune are from the track has resonance with the relationship between the composition of celestial bodies (when the sun neptune revolution around the sun three times on the second lap, or Neptune revolution only twice绕一圈), in fact, Neptune itself is in resonance with one. Traditional members are not with the Neptune resonance, scattered in astronomical units from 39.4 to 47.7 within the scope of celestial bodies. Traditional KBO was discovered in the first three of the name of one of 1992 QB1, QB1 was classified as a category of celestial bodies.

Pluto and Charon

[Pluto and the three satellites known]

Pluto and the three satellites known

Pluto (Pluto) (average distance of 39 astronomical units) is a dwarf planet, but also within the Kuiper Belt, one of the largest known celestial bodies. When it was discovered in 1930 was considered the ninth planet until 2006 before re-classified as a dwarf planet. Pluto’s orbit to the ecliptic plane is tilted 17 degrees, with the sun’s distance from points in the next few days are 29.7 astronomical units (in the medial orbit of Neptune), aphelion when it reached 49.5 astronomical units.

Is still not sure Charon (Charon) should be classified as current or belonging to consider satellite dwarf planet, because Pluto and Charon orbit each other around the center of mass is not any one person under the surface, forming a Pluto – Charon binary system. Other two small satellite Nicks (Nix) and Hsu la (Hydra), while around Pluto and戎公turn card.

Pluto brought in resonance with the 3:2 resonance with Neptune (Pluto around the sun, when the Second Circle, Neptune revolution three times). Kuiper belt objects have orbits that are collectively referred to as category objects offerings.

Discrete plate

Discrete plate and Kuiper Belt are overlapping, but extends to more distant space. Discrete set of celestial bodies should be formed in the early solar system process, because Neptune outward migration was caused by gravitational perturbations from the Kuiper Belt into orbits volatile. Ecliptic most recent point of discrete objects in the Kuiper Belt, but can be much aphelion to 150 astronomical units; orbit on the ecliptic plane also has a great angle, and even perpendicular to the ecliptic plane. Some astronomers think the ecliptic discrete Kuiper Belt objects should be the other part, and should be referred to as the “Kuiper Belt discrete objects.”

God quarrel stars

God Star quarrel (136199 Eris) (average distance of 68 astronomical units) is the biggest known discrete celestial ecliptic, and triggered a debate on what is a planet. The diameter of him at least 15 percent more than Pluto large, an estimated 2400 kilometers (1500 miles), are known dwarf planet in the biggest. God has a quarrel Star satellites, one quarrel Wei (Dysnomia), orbit like Pluto has a lot of the same eccentricity, perihelion distance is 38.2 astronomical units (about Pluto and the sun are the average distance), far points to reach 97.6 astronomical day units, on the ecliptic plane of the tilt angle is also very strong.

5. Farthest Regional

Where the end of the solar system, as well as the location of the beginning of interstellar medium is not a clear definition of the boundaries, because it required by the solar wind and solar gravitational force between the two to decide. Solar wind affects the distance from the interstellar medium are around four times the distance of Pluto, but the sun lochy ball, that is, the Sun cited the limits of its resources should be thousands of times over this distance.

Heliospheric Top

Solar circle can be divided into two regions, the solar wind passing around the maximum distance at 95 astronomical units, which is three times Pluto’s orbit Department. Here are the brink of terminal shock wave, that is, the solar wind and interstellar medium collide with each other and of the impulse. The solar wind deceleration in here, pool and become more chaotic, and form a huge oval structure, which is the so-called sheath day, appearance and performance are like tail in the direction towards the stellar wind extends outward to about 40 astronomical units, but the opposite direction of the end of this distance was extended several times. Circle the outer edge of the solar day are top of the ball layer, here are the solar wind termination of the last of the outside is interstellar space Constant.

Outside edge of the solar shape and form are likely to be interaction with the interstellar matter of the impact of fluid dynamics, but also be dominant in the southern tip of the impact of the solar magnetic field; For example, it forms in the northern hemisphere than the Southern Hemisphere expands many astronomical 9 units (about 1.5 billion kilometers). Day ball in the top layer, the astronomical unit in around 230 offices, there is a bow shock, which is when the sun in the Milky Way through generated.

Has not to date the spacecraft flew over the ball outside the top layer, so also is unable to ascertain the environmental conditions in interstellar space. How to protect the solar circle of cosmic rays in the solar system, at present know very little about. For this reason, people have begun to be able to circle the sun flying over the mission.

Oort Cloud (Oort cloud)

Are surrounded by a hypothetical spherical cloud the solar system, filled with a lot of inactive comets, the solar distance of about 5-10000 astronomical units, almost equivalent to one light-years, that is, next to the sun and stars (Proxima) distance of a quarter.

Theoretical Oort cloud hundreds of megabytes of enormous icy celestial bodies and the quality of astronomical units in about 5000, up to 10,000 astronomical units furthest distance surrounded by the solar system, is considered a source of long-period comets. They are considered to extrasolar planets by the gravitational effect of the solar system from the inside was thrown to the comet. Oort cloud objects exercise very slowly and can be subject to a number of unusual conditions, such as collisions, or the gravitational effects of celestial bodies, or tidal galaxies.

Sedna and the inner Oort Cloud

Sedna (Sedna) are enormous stars, the red of the class offerings of celestial bodies, the recent astronomical units in 76 points, far in the 928 day astronomical units, 12,050 years to complete a week of huge, high-elliptical orbit rate. Meters high in 2003, Brown discovered the bodies, because of its perihelion is too far, resulting in migration of Neptune can not be affected, so think it is not discrete plate or Kuiper Belt members. He and other astronomers think it belongs to a new classification, belong to this new ethnic groups have in recent days in the 45 astronomical units, far in the 415 day astronomical unit, orbital cycle in 3420 the 2000 CR105, and recently in the 21 astronomical units , far in the 1000 date astronomical unit, 12,705-year orbit cycle (87269) 2000 OO67. Brown named this group of people as “within the Oort cloud”, although it was far away from the sun but still close to, possibly through a similar process of formation. Sedna shape has been confirmed that a very short like a planet.

Borders

Our solar system there are still many unknowns. Consideration of neighboring stars, it is estimated that the Sun’s gravity can control 2 light years (125,000 astronomical units) range. Oort cloud extends the extent of perhaps not more than 50,000 astronomical units. Despite the discovery of Sedna, the scope of the Kuiper Belt and Oort cloud between, there are still tens of thousands of astronomical units in radius of the region are not being detectable. Between Mercury and the Sun are still continuing regional study. Unknown regions in the solar system may still be found.

Dwarf planet

Dwarf planets are from Pluto (Pluto), Ceres (Ceres), Star Xena (Xena) and Charon stars (Charon)