arboletum

On 5 October 1896 Antonio Lussich bought a terrain of 4,447 acres (1,800 hectares), which extend from "Arroyo el Potrero" to "Sierra de la Ballena" and from Rio de la Plata to Laguna del Sauce, land which at that time consisted only of sand dunes and stones.
The next year Antonio Lussich started the forestry works which had as objective on one hand, to forest the dry lands in an attempt to stop the high winds that came from the ocean, and on the other, once the forest was established, to encourage birds to inhabit it.
In order to do that, Antonio Lussich, thanks to the enterprise of maritime rescue contracts obtained all over the world, could manage to get seeds from numerous continents. He bought seeds, plants and trees from around the world and planted them around his house.
The first trees planted were: Tamarix, Sea pines, Eucalyptus and the Acacia trinervis to resist the strong winds and sand.
During December 1979, 182ha (450 Acres approx.) was donated to the Municipality of Maldonado and then opened to the public.
The Arboretum Lussich is one of the most important Forest Reserves in the world



Species



The Arboretum Lussich has more than 400 Exotic species and around 70 Uruguayan species.
Between many of the trees species, the most important are:
Abies, 6 species.
Acacia, 8 species.
Cupressus, 9 species.
Eucalyptus, 45 species.
Juniperus, 10 species.
Pinus, 20 species.
Quercus, 16 species.
Thuja, 4 species.



Abies: White Fir (Abies concolor) is a fir native to the mountains of western North America, occurring at altitudes of 900-3,400 m. It is a medium to large evergreenconiferous tree growing to 25-60 m tall and with a trunk diameter of up to 2 m.




Acacia
Acacia pycnantha
The genus Acacia is apparently not monophyletic. This discovery has led to the breaking up of Acacia into five new genera as discussed in list of Acacia species.In common parlance the term "acacia" is occasionally misapplied to species of the genus Robinia, which also belongs in the pea family. Robinia pseudoacacia, an American species locally known as Black locust, is sometimes called "false acacia" in cultivation in the United Kingdom.



Cupressus: The genus Cupressus is one of several genera within the family Cupressaceae that have the common name cypress; for the others, see cypress (disambiguation).
As currently treated, these cypresses are native to scattered localities in mainly warm temperate regions in the northern hemisphere, including western North America, Central America, north-west Africa, the Middle East, the Himalaya, southern China and north Vietnam. They are evergreen trees or large shrubs, growing to 5-40 m tall. The leaves are scale-like, 2-6 mm long, arranged in opposite decussate pairs, and persist for 3-5 years. On young plants up to 1-2 years old, the leaves are needle-like, 5-15 mm long. The cones are 8-40 mm long, globose or ovoid with 4-14 scales arranged in opposite decussate pairs; they are mature in 18-24 months from pollination. The seeds are small, 4-7 mm long, with two narrow wings, one along each side of the seed. The genus Cupressus is one of several genera within the family Cupressaceae that have the common name cypress; for the others, see cypress (disambiguation).



Eucalyptus

Eucalyptus (pronounced /ˌjuːkəˈlɪptəs/[2] ) is a diverse genus of flowering trees (and a few shrubs) in the myrtle family, Myrtaceae. Members of the genus dominate the tree flora of Australia. There are more than 700 species of Eucalyptus, mostly native to Australia, and a very small number are found in adjacent parts of New Guinea and Indonesia and one as far north as the Philippines islands. Only 15 species occur outside Australia, and only 9 do not occur in Australia. Species of Eucalyptus are cultivated throughout the tropics and subtropics including the Americas, England, Africa, the Mediterranean Basin, the Middle East, China and the Indian Subcontinent.



Junipers


Junipers vary in size and shape from tall trees, 20-40 m tall, to columnar or low spreading shrubs with long trailing branches. They are evergreen with needle-like and/or scale-like leaves. They can be either monoecious or dioecious. The female seed cones are very distinctive, with fleshy, fruit-like coalescing scales which fuse together to form a "berry"-like structure, 4-27 mm long, with 1-12 unwinged, hard-shelled seeds. In some species these "berries" are red-brown or orange but in most they are blue; they are often aromatic (for their use as a spice, see juniper berry). The seed maturation time varies between species from 6-18 months after pollination. The male cones are similar to those of other Cupressaceae, with 6-20 scales; most shed their pollen in early spring, but some species pollinate in the autumn.



Pines


Pines are coniferous trees in the genus Pinus (pronounced /ˈpaɪnəs/),[1] in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.
Pines are native to most of the Northern Hemisphere. In Eurasia, they range from the Canary Islands and Scotland east to the Russian Far East, and in the Philippines, north to just over 70°N in Norway (Scots Pine) and eastern Siberia (Siberian Dwarf Pine), and south to northernmost Africa, the Himalaya and Southeast Asia, with one species (Sumatran Pine) just crossing the Equator in Sumatra to 2°S. In North America, they range from 66°N in Canada (Jack Pine) south to 12°N in Nicaragua (Caribbean Pine). The highest diversity in the genus occurs in Mexico and California.




Quercus


The term oak can be used as part of the common name of any of about 400 species of trees and shrubs in the genus Quercus (pronounced /ˈkwɜrkəs/;[1] Latin "oak tree"), which are listed in the List of Quercus species, and some related genera, notably Lithocarpus. The genus is native to the northern hemisphere, and includes deciduous and evergreen species extending from cold latitudes to tropical Asia and the Americas.
Oaks have spirally arranged leaves, with a lobed margin in many species; some have serrated leaves or entire leaves with a smooth margin. The flowers are catkins, produced in spring. The fruit is a nut called an acorn, borne in a cup-like structure known as a cupule; each acorn contains one seed (rarely two or three) and takes 6–18 months to mature, depending on species. The "live oaks" (oaks with evergreen leaves) are not a distinct group, instead with their members scattered among the sections below


Antonio lussich


Arboretum


On 5 October 1896 he acquired 4,447 acres (18 km2) of uninhabited land at Punta Ballena. At this location he started his masterpiece, the creation of the Arboretum Lussich, a huge natural botany garden.
He owned part of his father's maritime rescue enterprise which he sold in 1917 so he could dedicate his full time to his passion.

astronomy

History of astronomy

Astronomy is the oldest of the natural sciences, dating back to antiquity, with its origins in the religious, mythological, and astrological practices of pre-history: vestiges of these are still found in astrology, a discipline long interwoven with public and governmental astronomy, and not completely disentangled from it until a few centuries ago in the Western World (see astrology and astronomy). Early astronomy involved observing the regular patterns of the motions of visible celestial objects, especially the Sun, Moon, stars and naked eye planets. An example of this early astronomy might involve a study of the changing position of the Sun along the horizon or the changing appearances of stars in the course of the year, which could be used to establish an agricultural or ritual calendar. In some cultures astronomical data was used for astrological prognostication.

People in the history

Background
Pythagoras
Ptolemy
Copernicus
Johannes Kepler
Galileo Galilei
Sir Isaac Newton
Edmund Halley
Albert Einstein
Stephen Hawking

What is the Universe?

The Universe is defined as everything that physically exists: the entirety of space and time, all forms of matter, energy and momentum, and the physical laws and constants that govern them. However, the term Universe may be used in slightly different contextual senses, denoting such concepts as the cosmos, the world or Nature

Milky Way

The Milky Way is the galaxy which is the home of our Solar System together with at least 200 billion other stars (more recent estimates have given numbers around 400 billion) and their planets, and thousands of clusters and nebulae, including at least almost all objects of Messier's catalog which are not galaxies on their own (one might consider two globular clusters as possible exceptions, as probably they are just being, or have recently been, incorporated or imported into our Galaxy from dwarf galaxies which are currently in close encounters with the Milky Way: M54 from SagDEG, and possibly M79 from the Canis Major Dwarf). See our Messier Objects in the Milky Way page, where details are given for each object to which part of our Galaxy it is related. All the objects in the Milky Way Galaxy orbit their common center of mass, called the Galactic Center (see below).

The Sun

The Sun (Latin: Sol), a yellow dwarf, is the star at the center of the Solar System. The Earth and other matter (including other planets, asteroids, meteoroids, comets, and dust) orbit the Sun,[9] which by itself accounts for about 98.6% of the Solar System's mass. The mean distance of the Sun from the Earth is approximately 149,600,000 kilometers, or 92,960,000 miles, and its light travels this distance in 8 minutes and 19 seconds. Energy from the Sun, in the form of sunlight, supports almost all life on Earth via photosynthesis,[10] and drives the Earth's climate and weather.

The moon

The Moon (Latin: Luna) is Earth's only natural satellite and the fifth largest satellite in the Solar System. The average centre-to-centre distance from the Earth to the Moon is 384,403 km, about thirty times the diameter of the Earth. The common centre of mass of the system (the barycentre) is located about 1,700 km—a quarter the Earth's radius—beneath the surface of the Earth. The Moon makes a complete orbit around the Earth every 27.3 days (the orbital period), and the periodic variations in the geometry of the Earth–Moon–Sun system are responsible for the lunar phases that repeat every 29.5 days (the synodic period).

Comets

A comet is a Small Solar System Body that orbits the Sun. When close enough to the Sun, a comet exhibits a visible coma (fuzzy "atmosphere"), and sometimes a tail, both because of the effects of solar radiation upon the comet's nucleus. Comet nuclei are themselves loose collections of ice, dust and small rocky particles, ranging from a few kilometers to tens of kilometers across. The word "comet" came to the English language through the Latin cometes from the Greek word komē, meaning "hair of the head"; Aristotle first used the derivation komētēs to depict comets as "stars with hair." The astronomical symbol for comets (☄) accordingly consists of a disc with a hairlike tail.

Planets
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.


The Earth
Earth, our home planet, is a beautiful blue and white ball when seen from space. The third planet from the Sun, it is the largest of the inner planets. Earth is the only planet known to support life and to have liquid water at the surface

The atmosphere
The atmosphere surrounds Earth and protects us by blocking out dangerous rays from the sun. The atmosphere is a mixture of gases that becomes thinner until it gradually reaches space. It is composed of Nitrogen (78%), Oxygen (21%), and other gases (1%).
Oxygen is essential to life because it allows us to breathe. Some of the oxygen has changed over time to ozone. The the ozone layer filters out the sun's harmful rays. Recently, there have been many studies on how humans have caused a hole in the ozone layer.
Humans are also affecting Earth's atmosphere through the greenhouse effect. Due to increases in gases, like carbon dioxide, that trap heat being radiated from the Earth, scientists believe that the atmosphere is having trouble staying in balance creating the greenhouse effect .
The atmosphere is divided into five layers depending on how temperature changes with height. Most of the weather and clouds are found in the first layer.

The forest

The forest is a complex ecosystem consisting mainly of trees that buffer the earth and support a myriad of life forms. The trees help create a special environment which, in turn, affects the kinds of animals and plants that can exist in the forest. Trees are an important component of the environment. They clean the air, cool it on hot days, conserve heat at night, and act as excellent sound absorbers.

Arboletum lussich

On October 5, 1896, Antonio Lussich, owner of a marine salvage company, bought a plot of 1800 hectares, extending from the Potrero Creek in the Sierra de la Ballena and the Silver River to the Laguna del Sauce , at which time there were only rocks and sand dunes. The following year Lussich Antonio began the work of afforestation which were, first afforest the hills, trying to stop the winds, and secondly, once formed the woods, populated with birds. To this end Antonio Lussich through the maritime salvage company and earned worldwide contacts, it was able to obtain seeds and plants from all continents. In an unprecedented move for the time purchased plants and trees from all regions of the world, and next to the mansion as his residence, built sombráculos for plants and aviaries for birds brought in from around the world.
The east side of the mountains, sheltered from the strongest winds from the southwest, was the place for the preparation of seedlings and nursery. Once germinated, and with some development, the plants were carried by the thousands across the mountains, without the shelter. The first to be planted were Tamarix, maritime pines, Eucalyptus and Acacia trinervis to fight the wind and sand. After 30 years were introduced during the most diverse. In December 1979, 182 has passed into the hands of the Municipality of Maldonado, who after being reconditioned, are open to the public. The year 1990 has added 10 more to the 192 currently has the Park. The Arboretum is one of the largest forest reserves worldwide.

the planets

The planets

• The planets turn about the Sun. They do not have proper light, but they reflect the solar light.

• The planets have diverse movements. The most important are two: that of rotation and that of movement. For that of rotation, they turn on yes same about the axis. Ésto determines the duration of the day of the planet. For that of movement, the planets describe orbits about the Sun. Every orbit is the year of the planet. Every planet takes a different time to complete it. Further,more time. They turn almost in the same plane, except Pluto, which has the most sloping, eccentric and elongated orbit.

• Form and size of the planets

• The planets take almost spherical form an as as a ball a little smoothed by the poles.

• The compact materials are in the nucleus. The gases, if there is, form an ambience on the surface. Mercury, Venus, the Earth, Mars and Pluto are small and rocky planets, with high thickness. They have a slow movement of rotation, few lunas (or none) and quite round form. Júpiter, Saturn, Uranus and Neptune, the gaseous giants, are enormous and light, a gas facts and ice. These planets turn quickly and have many satellites, more equatorial abultamiento and rings.

• The planets formed approximately 4.500 million years ago, at the same time that the Sun.

• In general, the light materials that did not remain in the Sun moved away more than the heavy ones. In the gas cloud and original dust, which was turning in spirals, there were denser zones, projects of planets. The gravity and the collisions took more matter to these zones and the rotary movement rounded them Later, the materials and the forces of every planet were readjusting, and they still do it. The planets and the whole Solar System keep on changing aspect. Without hurry, but without break.

Mercury
It is the planet of the Solar System most next to the Sun, and the smallest (with the exception of the dwarf planets). It is a part of the so called interior or rocky planets. Mercury has no satellites. Very little was known on his surface until there was sent the planetary probe Mariner 10, and remarks did with radars and radio-telescopes.Formerly it was thought that Mercury was always presenting the same one facing the Sun, situation similar to the case of the Moon with the Earth; that is to say, that his period of rotation was equal to his period of movement, both of 88 days. Nevertheless, in 1965 they got about by pulses of radar towards Mercury, with which he remained definitively demonstrated that his period of rotation was 58,7 days, which is 2/3 of his period of movement. This is not a coincidence, and it is a situation so called orbital resonance.

Venus
It is the second planet of the Solar System in order of distance from the Sun, and the third one as for size (of minor to major). It receives his name in honor to Venus, the Roman goddess of the love. It is a question of a planet of terrestrial or telluric type, called often the planet brother of the Earth, since both are similar as for size, mass and composition. The orbit of Venus is an ellipse with an eccentricity of less than 1 %, practically a circumference

•On having been Venus nearer to the Sun that the Earth, it is always possible to find, approximately, in the same direction of the Sun (his biggest elongation is of 47,8th), from what from the Earth it is possible to see only a few hours before other or after the west. In spite of it, when Venus is more brilliant it can be seen during the day, being one of three only celestial bodies that can be seen so much in the daytime as at night (others are the Moon and the Sun). Venus is normally an acquaintance as the star of the morning (Star of Alba) or the star of the evening (Star Vespertino) and, when it is visible in the night sky, is the most brilliant object of the firmament, apart from the Moon.

The Earth
it is the third planet of the Solar System (counting in order of distance of eight planets to the Sun), and the quarter of them of minor to major. It is placed to some 150millones of kilometers of the Sun. It is the only planet in which the existence of life is known. The Earth formed at the same time that the Sun and the rest of the Solar System, it does some 4570millones of years. The volume of the Earth is more than one minor million times that the Sun and the mass of the Earth is nine times major than that of his satellite, the Moon. The average temperature of the terrestrial surface is approximately 15 °C. In his origin, the Earth could have been only an aggregation of incandescent rocks and gases.

Mars

It is the fourth planet of the solar system. Acquaintance as the red planet for his pink tones, the Romans were identifying it with the blood and they put the name of his god of the war.• The planet Mars has a very thin ambience, formed principally by carbon dioxide, which freezes alternativamente in each of the poles. It contains only 0,03 % of water, thousand times less than the Earth.• The studies demonstrate that Mars had a more compact ambience, with clouds and precipitations that were forming rivers. On the surface adivinan ruts, islands and coasts.
jupiter

it is the fifth planet of the Solar System. It is a part of the so called exterior or gaseous planets. It receives his name of the Roman god Júpiter (Zeus in the Greek mythology).• it is a question of the planet that offers a major sheen throughout the year depending on his phase. It is, also, after the Sun the biggest celestial body of the Solar System, with a mass almost two times and average that of other together planets (318 times heavier than the Earth and 3 times more than Saturn).• Júpiter is a massive gaseous body, formed principally by hydrogen and helium lacking in an interior definite surface. Between the atmospheric details there stand out the Big red spot, an enormous anticyclone placed in the tropical latitudes of the south hemisphere, the structure of clouds in bands and zones, and the strong dynamics of zonal winds with speeds of up to 140 m/s (504 km/h).

Saturn
it is the sixth planet of the Solar System, it is the second one in size and mass after Júpiter and it is the only one with a visible system of rings from our planet. His name comes from the Roman god Saturn. It is a part of the so called exterior or gaseous planets, also called jovianos for his similar one to Júpiter. His brilliant rings are the aspect most typical of Saturn. Before the invention of the telescope, Saturn was the most distant of the well-known planets and, a simple sight, it seemed neither luminous nor interesting. The first one in observing the rings was Galilean in 1610 but the low inclination of the rings and the low resolution of his telescope made be thought by them about a beginning that was talking each other about big lunas. Christiaan Huygens with better means of observation could in 1659 observe with clarity the rings. James Clerk Maxwell in 1859 demonstrated mathematically that the rings could not be the only solid object but they had to be the grouping of millions of particle of minor size.

Uranus

it is the seventh planet of the Solar System, the third one in size, and the most massive quarter. The principal characteristic of Uranus is the inclination of his axis of rotation of almost ninety grades with regard to his orbit; the inclination not only limits itself to the same planet, but also to his rings, satellites and the magnetic field of the same one. Uranus possesses the most uniform surface of all the planets for his blue - greenish characteristic color produced by the combination of present gases in his ambience and has a system of rings that cannot be observed to simple sight. Also it possesses a blue ring, which is a planetary oddness. Uranus is one of two planets that has a retrograde movement, similar to that of Venus.

Neptune

it is the eighth and last planet of the Solar System. It is a part of the so called exterior planets or gaseous giants, and is the first one that was discovered thanks to mathematical prophecies. His name comes from the Roman god Neptune, the god of the sea.• After the discovery of Uranus, it was observed that the orbits of Uranus, Saturn and Júpiter were not behaving as there were predicting the laws of Kepler and of Newton. Adams and Verrier, of independent form, calculated the position of another planet, Neptune, which found Galle, September 23, 1846, at least of a grade of the position calculated by Adams and Him Verrier. Later, it was warned that Galilean he had already observed Neptune in 1611, but it had taken it as a star.• Neptune is a dynamic planet, with spots that remember the storms of Júpiter. The biggest, the Big Dark Spot, had a size similar to that of the Earth, but in 1994 it disappeared and other one has formed. The strongest winds of any planet of the Solar System are those of Neptune.

Sedna

•: The ninth planet of the Solar System?

• Sedna turns about the Sun at a distance much major than other stars of the system.

• Although his size is still uncertain, Sedna is the biggest of the planets located about the Sun from the discovery of Pluto in 1930. It is to more than 10,000 million kilometers of the Earth in a region called Belt of Kuiper, which has hundreds of well-known objects, small worlds of rock and ice, although some of them can be so or bigger than Pluto. Sedna is redder than any other body of the Solar System, except Mars, and it continues a very elliptical orbit, which in his most remote point places him to 135,000 million kilometers of the Sun. For it, Sedna needs 11,500 terrestrial years to complete an orbit.

los planetas

LOS PLANETAS

•Los planetas giran alrededor del Sol. No tienen luz propia, sino que reflejan la luz solar.

•Los planetas tienen diversos movimientos. Los más importantes son dos: el de rotación y el de translación. Por el de rotación, giran sobre sí mismos alrededor del eje. Ésto determina la duración del día del planeta. Por el de translación, los planetas describen órbitas alrededor del Sol. Cada órbita es el año del planeta. Cada planeta tarda un tiempo diferente para completarla. Cuanto más lejos, más tiempo. Giran casi en el mismo plano, excepto Plutón, que tiene la órbita más inclinada, excéntrica y alargada.

•Forma y tamaño de los planetas

•Los planetas tienen forma casi esférica, como una pelota un poco aplanada por los polos.

•Los materiales compactos están en el núcleo. Los gases, si hay, forman una atmosfera sobre la superficie. Mercurio, Venus, la Tierra, Marte y Plutón son planetas pequeños y rocosos, con densidad alta. Tienen un movimiento de rotación lento, pocas lunas (o ninguna) y forma bastante redonda. Júpiter, Saturno, Urano y Neptuno, los gigantes gaseosos, son enormes y ligeros, hechos de gas y hielo. Estos planetas giran deprisa y tienen muchos satélites, más abultamiento ecuatorial y anillos.

•Formación de los planetas

•Los planetas se formaron hace unos 4.500 millones de años, al mismo tiempo que el Sol.

•En general, los materiales ligeros que no se quedaron en el Sol se alejaron más que los pesados. En la nube de gas y polvo original, que giraba en espirales, había zonas más densas, proyectos de planetas. La gravedad y las colisiones llevaron más materia a estas zonas y el movimiento rotatorio las redondeó Después, los materiales y las fuerzas de cada planeta se fueron reajustando, y todavía lo hacen. Los planetas y todo el Sistema Solar continúan cambiando de aspecto. Sin prisa, pero sin pausa.

Mercurio

Es el planeta del Sistema Solar más próximo al Sol, y el más pequeño (a excepción de los planetas enanos). Forma parte de los denominados planetas interiores o rocosos. Mercurio no tiene satélites. Se conocía muy poco sobre su superficie hasta que fue enviada la sonda planetaria Mariner 10, y se hicieron observaciones con radares y radiotelescopios.
Antiguamente se pensaba que Mercurio siempre presentaba la misma cara al Sol, situación similar al caso de la Luna con la Tierra; es decir, que su periodo de rotación era igual a su periodo de traslación, ambos de 88 días. Sin embargo, en 1965 se mandaron pulsos de radar hacia Mercurio, con lo cual quedó definitivamente demostrado que su periodo de rotación era de 58,7 días, lo cual es 2/3 de su periodo de traslación. Esto no es coincidencia, y es una situación denominada resonancia orbital.

Venus

Es el segundo planeta del Sistema Solar en orden de distancia desde el Sol, y el tercero en cuanto a tamaño (de menor a mayor). Recibe su nombre en honor a Venus, la diosa romana del amor. Se trata de un planeta de tipo terrestre o telúrico, llamado con frecuencia el planeta hermano de la Tierra, ya que ambos son similares en cuanto a tamaño, masa y composición. La órbita de Venus es una elipse con una excentricidad de menos del 1%, prácticamente una circunferencia.

•Al encontrarse Venus más cercano al Sol que la Tierra, siempre se puede encontrar, aproximadamente, en la misma dirección del Sol (su mayor elongación es de 47,8º), por lo que desde la Tierra se puede ver sólo unas cuantas horas antes del otro o después del ocaso. A pesar de ello, cuando Venus es más brillante puede ser visto durante el día, siendo uno de los tres únicos cuerpos celestes que pueden ser vistos tanto de día como de noche (los otros son la Luna y el Sol). Venus es normalmente conocido como la estrella de la mañana (Lucero del Alba) o la estrella de la tarde (Lucero Vespertino) y, cuando es visible en el cielo nocturno, es el objeto más brillante del firmamento, aparte de la Luna.

La Tierra

es el tercer planeta del Sistema Solar (contando en orden de distancia de los ocho planetas al Sol), y el cuarto de ellos de menor a mayor. Está situada a unos 150millones de kilómetros del Sol. Es el único planeta en el que se conoce la existencia de vida. La Tierra se formó al mismo tiempo que el Sol y el resto del Sistema Solar, hace unos 4570millones de años. El volumen de la Tierra es más de un millón de veces menor que el Sol y la masa de la Tierra es nueve veces mayor que la de su satélite, la Luna. La temperatura media de la superficie terrestre es de unos 15 °C. En su origen, la Tierra pudo haber sido sólo un agregado de rocas incandescentes y gases.

Marte
•Es el cuarto planeta del sistema solar. Conocido como el planeta rojo por sus tonos rosados, los romanos lo identificaban con la sangre y le pusieron el nombre de su dios de la guerra.
•El planeta Marte tiene una atmósfera muy fina, formada principalmente por dióxido de carbono, que se congela alternativamente en cada uno de los polos. Contiene sólo un 0,03% de agua, mil veces menos que la Tierra.
•Los estudios demuestran que Marte tuvo una atmósfera más compacta, con nubes y precipitaciones que formaban rios. Sobre la superficie se adivinan surcos, islas y costas.

Júpiter

es el quinto planeta del Sistema Solar. Forma parte de los denominados planetas exteriores o gaseosos. Recibe su nombre del dios romano Júpiter (Zeus en la mitología griega).
•Se trata del planeta que ofrece un mayor brillo a lo largo del año dependiendo de su fase. Es, además, después del Sol el mayor cuerpo celeste del Sistema Solar, con una masa casi dos veces y media la de los demás planetas juntos (318 veces más pesado que la Tierra y 3 veces más que Saturno).
•Júpiter es un cuerpo masivo gaseoso, formado principalmente por hidrógeno y helio, carente de una superficie interior definida. Entre los detalles atmosféricos se destacan la Gran mancha roja, un enorme anticiclón situado en las latitudes tropicales del hemisferio sur, la estructura de nubes en bandas y zonas, y la fuerte dinámica de vientos zonales con velocidades de hasta 140 m/s (504 km/h).

Saturno

es el sexto planeta del Sistema Solar, es el segundo en tamaño y masa después de Júpiter y es el único con un sistema de anillos visible desde nuestro planeta. Su nombre proviene del dios romano Saturno. Forma parte de los denominados planetas exteriores o gaseosos, también llamados jovianos por su parecido a Júpiter. El aspecto más característico de Saturno son sus brillantes anillos. Antes de la invención del telescopio, Saturno era el más lejano de los planetas conocidos y, a simple vista, no parecía luminoso ni interesante. El primero en observar los anillos fue Galileo en 1610 pero la baja inclinación de los anillos y la baja resolución de su telescopio le hicieron pensar en un principio que se trataba de grandes lunas. Christiaan Huygens con mejores medios de observación pudo en 1659 observar con claridad los anillos. James Clerk Maxwell en 1859 demostró matemáticamente que los anillos no podían ser un único objeto sólido sino que debían ser la agrupación de millones de partículas de menor tamaño.

Urano

es el séptimo planeta del Sistema Solar, el tercero en tamaño, y el cuarto más masivo. La principal característica de Urano es la inclinación de su eje de rotación de casi noventa grados con respecto a su órbita; la inclinación no sólo se limita al mismo planeta, sino también a sus anillos, satélites y el campo magnético del mismo. Urano posee la superficie más uniforme de todos los planetas por su característico color azul-verdoso, producido por la combinación de gases presentes en su atmósfera y tiene un sistema de anillos que no se pueden observar a simple vista. Además posee un anillo azul, el cual es una rareza planetaria. Urano es uno de los dos planetas que tiene un movimiento retrógrado, similar al de Venus.

Neptuno

es el octavo y último planeta del Sistema Solar. Forma parte de los denominados planetas exteriores o gigantes gaseosos, y es el primero que fue descubierto gracias a predicciones matemáticas. Su nombre proviene del dios romano Neptuno, el dios del mar.
•Tras el descubrimiento de Urano, se observó que las órbitas de Urano, Saturno y Júpiter no se comportaban tal como predecían las leyes de Kepler y de Newton. Adams y Le Verrier, de forma independiente, calcularon la posición de otro planeta, Neptuno, que encontró Galle, el 23 de septiembre de 1846, a menos de un grado de la posición calculada por Adams y Le Verrier. Más tarde, se advirtió que Galileo ya había observado Neptuno en 1611, pero lo había tomado por una estrella.
•Neptuno es un planeta dinámico, con manchas que recuerdan las tempestades de Júpiter. La más grande, la Gran Mancha Oscura, tenía un tamaño similar al de la Tierra, pero en 1994 desapareció y se ha formado otra. Los vientos más fuertes de cualquier planeta del Sistema Solar son los de Neptuno.

Sedna
•¿El noveno planeta del Sistema Solar?

•Sedna gira alrededor del Sol a una distancia mucho mayor que otros astros del sistema.
•Aunque su tamaño aún es incierto, Sedna es el mayor de los planetas localizados alrededor del Sol desde el descubrimiento de Plutón en 1930. Está a más de 10,000 millones de kilómetros de la Tierra en una región llamada Cinturón de Kuiper, que tiene cientos de objetos conocidos, pequeños mundos de roca y hielo, aunque algunos pueden ser tan o más grandes que Plutón. Sedna es más rojo que cualquier otro cuerpo del Sistema Solar, excepto Marte, y sigue una órbita muy elíptica, que en su punto más alejado le sitúa a 135,000 millones de kilómetros del Sol. Por ello, Sedna necesita 11,500 años terrestres para completar una órbita.