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The Solar System is formed by a star to which we called Sun. The planets, the majority of the satellites and all the asteroids orbit around the Sun, in the same direction following elliptical orbits in timetable direction if it is observed from upon the North Pole of the Sun. The plane approximated in that they turn all these bodies denominates ecliptic. Some objects orbit with a especially high degree of inclination, as Pluto with an inclination with respect to the axis of the ecliptic of 18º, as well as one leaves important from the objects of the belt of Kuiper. According to their characteristics, and advancing of the interior to the outside, the bodies that form the Solar System are classified in: Sun. A star of spectral type G2 that contains more of 99% of the mass of the system. With a diameter of 1.400.000 km, one is made up, of a 75% of hydrogen, a 25% of helium and a small percentage of oxygen, carbon, iron and other elements. Planets. Divided in inner planets, also called terrestrial or telluric, and outer or giant planets. Between these last Jupiter and Saturn gaseous giants denominate themselves whereas Urano and Neptune usually name as frozen giants. All the giant planets have to his ring around. In 2006, a convention of astronomy in Europe declared to Pluto as planetoid due to its size, clearing it of the formal planet list. Dwarf planets. This new category inferior to planet created the Astronomical Union the International in August of 2006. One is bodies whose mass allows them to have spherical form, but is not the sufficient one to have attracted or expelled all the bodies to his around. Bodies as Pluto, Ceres, Makemake and Eris are within this category. Satellites. Bodies majors orbiting the planets, some of great size, as the Moon, in the Earth, Ganymede, in Jupiter or Titán, Saturn. Asteroids. Bodies smaller concentrates mainly in the asteroid belt between the orbits of Mars and Jupiter, and another one beyond Neptune. Its little mass does not allow them to have regular form. Objects of the belt of Kuiper. Objects frozen outer in stable orbits, the majors of which would be Sedna and Quaoar. Comets. Small frozen objects originating of the Cloud of Oort.

All the planets turn around the Sun following a way that is called “orbit?. It has elliptical form but they are of little “eccentricity? meaning that are almost circular. The planets turn on themselves, like the spins, in a tumbling on their own axis; they also accompany to the Sun in his movement around the center of the galaxy.


Solar System



Mercury is the planet nearest the smallest Sun and. Its distance to the Sun is (in average) of 58 million kilometers. As its orbit is very extended (eccentric) the planet approaches 46 million km of the Sun in the “perihelion? (distance nearer the Sun) and it moves away to 69 million kilometers in the “aphelion? (more distant distance). Tour around the Sun in 88 days.

Formerly one thought that Mercury always presented the same face to the Sun, situation similar to the case of the Moon with the Earth, that is to say, that its period of rotation was equal to its period of transfering, both of 88 days. Nevertheless, in 1965 radar pulses were sent towards Mercury, consequently was definitively demonstrated that its period of rotation was of 58.7 days, which is 2/3 of their period of transfering. This is not coincidence, and is a denominated situation orbital resonance. To the being a planet whose orbit is inner to the one of the Earth, Mercury periodically happens in front of the Sun, phenomenon that denominates transit (to see Mercury transit). Observations of their orbit through many years demonstrated that the perihelion turns 43? of arc more by century of the predicted thing by the classic mechanics of Newton. This discrepancy took to a French astronomer, Urbain Le Verrier to think that a planet near the Sun existed still more, to which they called Vulcano Planet, that disturbed the Mercury orbit. Now one knows that Vulcano does not exist; the correct explanation of the behavior of the Mercury perihelion is in the General Theory of Relativity.

As Mercury closely together is of the Sun, the temperature in the illuminated part is sufficient as to fuse the lead.

In 1974 the ship sounds Mariner 10 photographed more of the 40 percent of the Mercury surface. These images showed us that mercury is looked much like our Moon. In this planet the craters abound much that were caused pormeteoritos, that hit in their surface.

Mercury, for being so small, it does not have atmosphere, although it has a noble gas thin layer.


Distance to the Sun 0.38 UA - Diameter (T=1) 0.3824 - Mass (T=1) 0.0552 - Gravity (T=1) 0.39 - Year 88 d - Rotation 58.6 d



Although similarity to the Earth was believed, the certain thing is that it is completely different. Venus is the second planet of the Solar System in sequence of distance from the Sun, and the quarter as far as size (of minor to major). It receives his name in honor to Venus, the Roman goddess of the love. One is a planet of terrestrial or telluric type, call frequently the brother Earth planet, since both are similar as far as size, mass and composition. The orbit of Venus is an ellipse with an eccentricity of less than 1%, practically a circumference. When being Venus nearer the Sun that the Earth, always can be found, approximately, in the same direction of the Sun (its greater elongation is of 47,8º), reason why from the Earth it is possible to be seen only a few hours before orto or after the decline. In spite of it, when Venus is more shining can be seen during the day, being one of the three only celestial bodies that can by day be seen as much as at night (the other they are the Moon and the Sun). Venus normally is known as the star in the morning (Morning star) or the star in the afternoon (Lucero Vespertino) and, when he is visible in the sky nocturne, is the object most shining of the firmament, aside from the Moon. For this reason, Venus had already to be known from the prehistoric times. Their movements in the sky were known by the majority the old civilizations, having acquired importance in almost all the astrological interpretations of the planetary movement. In particular, the Mayan civilization made a religious calendar based on the cycles of Venus. The symbol of the Venus planet is a streamlined representation of the mirror of the Venus goddess: a circle with a small cross underneath, also used to denote feminine sex. It owns a very dense atmosphere, that surrounds completely to the planet. The pressure in the surface is equivalent to be to 1 km under the water. The temperature is highest, arriving until the 450 ºC. He is still more hot that Mercury, and unlike this one, where the poles are cold, the temperature is practically uniform in all the planet. Venus does not have satellites either

VENUS Distance to the Sun 0.723 UA - Diameter (T=1) 0.95 - Mass (T=1) 0.815 - Gravity (T=1) 0.87 - Year 224.7 d - Day (Retrógado) 243 d






The Earth

Our Earth planet is the third planet of the Solar System, whereas clause its distance to the Sun, and fifth of them according to its size. It is located approximately to about 150 million kilometers of the Sun. It is the only planet of the universe that knows in that it exists and the life is originated. The Earth formed at the same time as the Sun and the rest of the Solar System, make 4570 million years. The volume of the Earth is more of the million times smaller one than the Sun and the mass of the Earth is nine times greater than the one of its satellite, the Moon. The average temperature of the terrestrial surface is of about 15 ºC. In its origin, the Earth could have been only an aggregate of incandescent rocks and gases. To the Earth form (understood as the medium altitude of the sea or that would adopt the sea in the continents) geoide is denominated to him. Geoide is a surface similar to a sphere flattened by the poles (ellipsoid). Its diameter is of about 12 700 km, more than ten times the length of the Iberian Peninsula. The first cultures thought that the Earth was flat. Some eminent astronomers of the Antiquity raised the possibility that the Earth was not flat but spherical, since of that way many natural phenomena would have a logical explanation. Nevertheless, until century XVI it was not possible to be demonstrated that she was spherical, when Juan Sebastián Elcano completed the first return to the world on board a boat. To the set of disciplines that study the processes of diverse scales temporary and space that govern this planet is called geociencias or sciences to him of the Earth. The Earth is a planet whose surface is covered in a 70% of liquid water. He essentially remains surrounded in the atmosphere, composed of Nitrogen (75%) and Oxygen (23%). It presents a strong magnetic field due to the liquid iron layer that surrounds the nucleus. The Earth enjoys an enormous and near satellite, the Moon

of 1/4 of the terrestrial diameter. Until the moment it is the only planet in which the presence is known life


Distance to the Sun 1 UA - Diameter (T=1) 1 - Mass (T=1) 1 - Gravity (T=1) 1 - Year 365.24 d - Day 1 d -



Mars is the last one of inner planets. The temperatures vary from -133ºC to 27ºC are thought that in the past amounts of water existed in Mars great, reason why could have some type of life. Mars, nicknamed sometimes as the Red Planet, is the fourth planet of the Solar System. Form leaves from the telluric calls planets (of rocky nature, as the Earth) and is the inner planet more moved away to the Sun. It is, in many aspects, most similar to the Earth. Tycho Brahe measured with high accuracy the Mars movement in the sky. The data on the retirement pretend (bows) allowed Kepler to find the elliptical nature of their orbit and to determine the laws of the planetary movement known as laws Kepler. Form leaves from planets superiors for the Earth, that are those that never happens between the Sun and the Earth. Their phases are little noticeable, fact that is easy to demonstrate geometrically. Whereas clause the Sun-Earth-Mars triangle, the phase angle is the one that forms the seen Sun and the Earth from Mars. It reaches his maximum value in the quadratures when the STM triangle is Earth rectangle. For Mars, this phase angle is never greater of 42º, and its hunchbacked disc aspect is analogous to which it presents the Moon 3.5 days before or after the Full Moon. This phase, visible with a fan telescope, did not manage to be seen by Galileo, who only supposed his existence. Geologically they honor Monte Olimpo, (25 km of height) and the Marineris valley, a tube of 4,000 km and one depth among 2 and 7 km Mars have two tiny moons: Fobos and Deimos. Several ships have been sent Sounding to the surface of this planet


Distance to the Sun 1.52 UA - Diameter (T=1) 0.53 - Mass (T=1) 0.11 - Gravity (T=1) 0.38 - Year 687 d - Day 24.6 h







Jupiter is enormous, its mass is major that the one of all the other together planets. It is first of gaseous planets, characterized not to own a solid surface. Jupiter is the fifth planet of the Solar System. Form leaves from denominated outer or gaseous planets. It receives his name of the Roman God Jupiter (Zeus in Greek mythology). One is the planet that offers a greater brightness throughout the year following its phase. It is, in addition, after the Sun the greater celestial body of the Solar System, with a mass almost twice and average the one of other planets together (318 times heavier than the Earth and 3 times more than Saturn). Jupiter is a gaseous massive body, formed mainly by hydrogen and helium, devoid of a defined inner surface. Between the details atmospherics they stand out the Great red spot, an enormous anticyclone located in the tropical latitudes of the Southern Hemisphere, the zone and cloud band structure, and the strong zonal wind dynamics with speeds of up to 140 m/s (504 km/h). Jupiter has 16 satellites. Four greater: I, Europe, Calisto and Ganímedes are visible with prism binocular. They were shortages by Galileo and they served to him to establish the Heliocentric Theory.


Distance to the Sun 5.20 UA - Diameter (T=1) 11.19 - Mass (T=1) 317.83 - Gravity (T=1) 2.55 - Year 11.86 d - Day 9.8 h FONT>



Most beautiful of planets thanks to its spectacular ring. These have a diameter of 270,000 km and some hundreds of meters of thickness. Saturn is the sixth planet of the Solar System, is the second in size and mass after Jupiter and is the unique one with a visible ring system from our planet. Its name comes from the Roman God Saturn. Form leaves from denominated outer or gaseous planets, also called jovianos by its similarity to Jupiter. The aspect most characteristic of Saturn is their shining ring. Before the invention of the telescope, Saturn was most distant of well-known planets and, at first, it did not seem luminous nor interesting. First in observing the ring she was Galileo in 1610 but the low inclination of the ring and the low resolution of their telescope made him think at first that it was great moons. Christiaan Huygens with better means of observation could in 1659 observe with clarity the ring. James Clerk Maxwell in 1859 demonstrated mathematically that the ring could not be an only solid object but they had to be the grouping of million smaller particles. Saturn is the less dense planet of the Solar System, its mass is the third part of Jupiter, being its similar size Has 18 well-known satellites. One of them, Titan, is major that Mercury.


Distance to the Sun 9.55 UA - Diameter (T=1) 9.41 - Mass (T=1) 95.14 - Gravity (T=1) 0.93 - Year 29.46 d - Day 10.2 d






Although he is easily visible from the Earth, it was not discovered to 1,781, previously had thought that it was a star. Uranus was the first planet shortage that was not well-known in the antiquity, although yes had been observed and confused with a star in many occasions. The registry older than is of him is due to John Flamsteed, who catalogued it as the star 34 Tauri in 1690. Sir William Herschel, a German musician in the court of king Jorge III of England, discovered the planet the 13 of March of 1781, using a telescope constructed by the same, although at first it reported that it was a comet. [1] Initially gave the name him of Georgium Sidus (the star of Jorge) in honor to the king who finished losing the British colonies in America, but had gained a star. Nevertheless, the name did not last beyond Great Britain, and Lalande, a French astronomer, proposed to call it Herschel in honor of its discoverer. Finally, the German astronomer Johann Elert Bode proposed the name of Uranus in honor to the Greek God, father of Time-trial (whose Roman equivalent gave name to Saturn). [2] Towards 1827, Uranus was the used name more for the planet even in Great Britain. The HM Nautical Almanac continued listing it as Georgium Sidus until the year of 1850. The axis of Uranus rotation almost points at the Sun, turning the planet knocked down in its orbit Has 20 satellites, 5 still without name. Also it has ring, although as in Jupiter they are dark and therefore little visible As a Neptune, the methane that contains the atmosphere is the one that gives its characteristic color them.


Distance to the Sun 19.22 UA - Diameter (T=1) 3.88 - Mass (T=1) 14.56 - Gravity (T=1) 0.99 - Year 84.01 to - Day 17.9 h



Neptune is the eighth and I complete planet of the Solar System. Form leaves from the denominated gaseous outer or giant planets, and is first that were shortage thanks to mathematical predictions. Its name comes from the Roman God Neptune, the God of the sea. After the Uranus discovery, it was observed that the orbits of Uranus, Saturn and Jupiter did not behave as they predicted the laws of Kepler and Newton. The Adams and It Verrier, independently, calculated the position of another planet, Neptune, that found Galle, the 23 of September of 1846, to less than a degree of the position calculated by Adams and Him Verrier. Later, one noticed that Galileo already had observed Neptune in 1611, but she had taken it by a star. Neptune is a dynamic planet, with spots that remember Jupiter storms. Greatest, the Great Dark Spot, had a size similar to the one of the Earth, but in 1994 it disappeared and another one has formed. The strongest winds of any planet of the Solar System are those of Neptune. He is densest of gaseous planets. Probably it has a nucleus of ice and rocks fused in his interior. The atmosphere of Neptune is shaken by winds of more than the 2,000 km/h, fastest of all the planets. Also it has ring and 8 satellites. One of them is the one of more elliptical orbit of all the well-known and another tour in sense in opposition to the rest. As the Pluto orbit is quite eccentric, Neptune has been from 1,978 to the 2,000 the moved away planet more of the Sun


Distance to the Sun 30.11 UA - Diameter (T=1) 3.81 - Mass (T=1) 17.22 - Gravity (T=1) 1.38 - Year 164.78 to - Day 19.1 h






Pluto is a dwarf planet (In the General Assembly of Unión Astronómica Internacional (UAI) celebrated in the Prague the 24 of August of 2006 a new called category has been created plutoid in which it is included to Pluto, replacing the dwarf planet name) that comprises of a planetary system doubles with Charon. It is also the prototype of a category of plutinos transneptunian objects denominated, and also of the plutoids. It owns an eccentric orbit and highly inclined with respect to the ecliptic, that it crosses approaching in his perihelion until the interior of the orbit of Neptune. The Pluto-Charon system owns two satellites: Nix and Hidra. These are celestial bodies that share the same category. Until the moment it has not been visited by any space probe, although one hopes that the New Horizons mission of the NASA flies over it in 2015. Charon, is half of the diameter of Pluto. The mass of both is 1/400 of the terrestrial one. The 18 of February of 1930 by the American astronomer were shortage Clyde William Tombaugh (1906-1997) from the Lowell Observatory in Flagstaff, Arizona, and the considered ninth and smaller planet of the Solar System by the Astronomical Union the International and the public opinion since then to 2006, although its property to the planet group of the Solar System was always object of controversy between the astronomers. After an intense debate, the UAI decided the 24 of August of 2006, unanimously, to reclassify Pluto as dwarf planet, requiring that a planet must “clear the surroundings of its orbit?. Its classification as planet in the resolution rough draft seted out, but it disappeared of the final resolution, approved by the General Assembly of the UAI. From the 7 of September of 2006 it has number 134340, granted by Minor Planet Center. It owns a rarefied atmosphere and delgadísima, its pressure does not reach 1/100,000 of the one of the Earth. A year in Pluto lasts almost 248 years.


Distance to the Sun 39.53 UA - Diameter (T=1) 0.39 - Mass (T=1) 0.0017 - Gravity (T=1) 0,00? - Year 247.67 to - Day 6.39 d


Other Celestial Bodies Comets

The comets are the travellers of the space. They are characterized by his tail, that appears in the neighborhoods of the Sun. The comets are small stars, composed of mixed dirty ice with gases. The Sun evaporates part of the nucleus, coming off itself gas particles and dust, that constitute the hair or tail. The tail always opposed trained of the Sun. Many comets return to happen near the Sun with total regularity. One very known is the Halley comet, that spends every 76 years. The dust sign that leaves behind himself a comet causes star rains sometimes, indeed when the Earth crosses its orbit.