Forest Rain

A forest is an area with a high density of trees. There are many definitions of a forest, based on various criteria. These plant communities cover approximately 9.4% of the Earth's surface (or 30% of total land area) and function as habitats for organisms, hydrologic flow modulators, and soil conservers, constituting one of the most important aspects of the Earth's biosphere. Historically, "forest" meant an uncultivated area legally set aside for hunting by feudal nobility, and these hunting forests were not necessarily wooded much if at all (see Royal Forest). However, as hunting forests did often include considerable areas of woodland, the word forest eventually came to mean wooded land more generally. A woodland is ecologically distinct from a forest.

Lake Placid - Cairns Australia

Lake Placid was founded in the early 1800s to develop a mining operation based on iron ore discovered nearby. By 1840, the population of "North Elba" (four miles southeast of the present village near where the road to the Adirondack Loj crosses the Ausable River) consisted of six families. In 1845, Gerrit Smith arrived in North Elba and not only bought a great deal of land around the village, he also granted large tracts to his slaves, reforming the land law and reflecting his support of Abolitionism.

The abolitionist John Brown heard about Gerrit Smith's reforms, and left his anti-slavery activities in Kansas to buy 244 acres (1.0 km²) of land, which later became known as the "Freed Slave Utopian Experiment," Timbucto. Upon his execution in 1859, John Brown asked to be buried on his farm, which is preserved as the John Brown Farm State Historic Site.

As leisure time increased in the late 19th century, Lake Placid was discovered by the rich and famous, who were drawn to the fashionable Lake Placid Club. Melvil Dewey, inventor of the Dewey Decimal System, designed what was then called "Placid Park Club" in 1895 and inspired the village to change its name to Lake Placid. Dewey kept the club open through the winter in 1905, which aided the development of winter sports in the area (although nearby Saranac Lake had hosted an international winter sporting event as early as 1889). By 1921, the area could boast a ski jump, speed skating venue and ski association, and in 1929, Dr. Godfrey Dewey, Melvil's son, was able to convince the International Olympic Committee (IOC) that Lake Placid had the best winter sports facilities in the nation. The Lake Placid Club was the headquarters for the IOC for the 1932 and the 1980 Winter Olympics in Lake Placid.

Lake Placid became an incorporated village in 1900.

Amazon River

The Amazon River (Portuguese: Rio Amazonas; Spanish: Río Amazonas) of South America is the largest river in the world by volume, with a total river flow greater than the next top ten largest rivers flowing into the ocean combined. The Amazon, which has the largest drainage basin in the world, accounts for approximately one fifth of the world's total river flow. Because of its vast dimensions, it is sometimes called The River Sea. At no point is the Amazon crossed by bridges. This is only partly because of its huge dimensions—for most of its length the Amazon is not so wide that a modern bridge could not span it—but also because, for most of its length, the river flows through tropical rainforest, where there are few roads and even fewer cities.

While the Amazon is clearly the largest river in the world by most measures, the majority of the geographic community today regards the Amazon as the second longest river, just slightly shorter than the Nile. However the discovery of a new tributary of the Amazon now leads some scientists to consider the Amazon as the longest river in the world.

Great White Shark

Sharks (superorder Selachimorpha) are a type of fish with a full cartilaginous skeleton and a streamlined body. They respire with the use of five to seven gill slits. Sharks have a covering of dermal denticles that protect their skin from damage and parasites and improve fluid dynamics; they also have replaceable teeth. Sharks range in size from the small dwarf lanternshark, Etmopterus perryi, a deep sea species of only 17 centimetres (7 in) in length, to the whale shark, Rhincodon typus, the largest fish, which grows to a length of approximately 12 metres (39 ft) and which, like baleen whales, feeds only on plankton, squid, and small fish through filter feeding. The bull shark. Carcharhinus leucas, is the best known of several species to swim in both salt, freshwater and in deltas.

Christian the Lion - the full story (in HQ)

The lion (Panthera leo) is a member of the family Felidae and one of four big cats in the genus Panthera. With exceptionally large males exceeding 250 kg (550 lb) in weight,^[3] it is the second-largest living cat after the tiger. Wild lions currently exist in Sub-Saharan Africa and in Asia with a critically endangered remnant population in northwest India, having disappeared from North Africa, the Middle East, and Western Asia in historic times. Until the late Pleistocene (about 10,000 years ago), the lion was the most widespread large land mammal beside humans. They were found in most of Africa, much of Eurasia from western Europe to India and, in the Americas, from the Yukon to Peru.

Should they survive the rigors of cubhood, lionesses in secure habitat such as Kruger National Park may frequently reach an age of 12–14 years whereas lions seldom live for longer than 8 years. However, there are records of lionesses living for up to 20 years in the wild. In captivity both male and female lions can live for over 20 years. They typically inhabit savanna and grassland, although they may take to bush and forest. Lions are unusually social compared to other cats. A pride of lions consists of related females and offspring and a small number of adult males. Groups of female lions typically hunt together, preying mostly on large ungulates. The lion is an apex and keystone predator, although they will resort to scavenging if the opportunity arises. While lions, in general, do not selectively hunt humans, some have been known to become man-eaters and seek human prey.

The lion is a vulnerable species, having seen a possibly irreversible population decline of 30 to 50 percent over the past two decades in its African range; populations are untenable outside designated reserves and national parks. Although the cause of the decline is not well understood, habitat loss and conflicts with humans are currently the greatest causes of concern. Lions have been kept in menageries since Roman times and have been a key species sought after and exhibited in zoos the world over since the late eighteenth century. Zoos are cooperating worldwide in breeding programs for the endangered Asiatic subspecies.

Visually, the male is highly distinctive and is easily recognized by its mane. The head of the male lion is one of the most widely recognized animal symbols in human culture. It has been depicted extensively in literature, in sculptures, in paintings, on national flags, and in contemporary films and literature.

The lioness has been recognized, however, as the pinnacle of hunting prowess from the earliest of human writings and graphic representations. The lionesses are the hunters for their pride and capture their prey with precise and complex teamwork. Each lioness develops specific skills for her role in the hunting techniques used by her pride and, generally, assumes that role during most hunts. Members of human cultures living among lions in natural habitats have understood this characteristic and often have chosen the lioness to represent their most ferocious war deities and warriors, often naming their male rulers as her "son". Examples drawn from the earliest of written records include the Egyptian pantheon deities of Sekhmet, Bast, Menhit, and Tefnut, and these deities may have had precursors in Nubia and Lybia. Other Egyptian deities are quite complex and assume aspects that may include one as a lioness headed human or a lioness in specific roles. Depictions of lions hunting in groups have existed from the Upper Paleolithic period, with carvings and paintings from the Lascaux and Chauvet Caves.

Panda Sneeze

The Giant Panda (Ailuropoda melanoleuca, "black-and-white cat-foot") is a mammal classified in the bear family (Ursidae), native to central-western and southwestern China. The panda was previously thought to be a member of the Procyonidae (raccoons and their relatives). It is easily recognized by its large, distinctive black patches around the eyes, over the ears, and across its round body. Though belonging to the order Carnivora, the panda has a diet which is 99% bamboo. Pandas may eat other foods such as honey, eggs, fish, yams, shrub leaves, oranges, and bananas when available.

Giant Pandas live in a few mountain ranges in central China, in Sichuan, Shaanxi, and Gansu provinces. They once lived in lowland areas, but farming, forest clearing, and other development now restrict giant pandas to the mountains.

The Giant Panda is an endangered species and highly threatened. According to the latest report,China has 239 giant pandas in captivity and another 27 pandas living outside the country. It also estimated that around 1,590 pandas are currently living in the wild. However, a 2006 study, via DNA analysis, estimated that there might be as many as 2,000 to 3,000 pandas in the wild. Though reports show that the numbers of wild pandas are on the rise, the International Union for Conservation of Nature believes there is not enough certainty to remove pandas from the endangered animal list.

While the dragon has historically served as China's national emblem, in recent decades the Giant Panda has also served as an emblem for the country. Its image appears on a large number of modern Chinese commemorative silver, gold, and platinum coins. The species is a favorite of the public, at least in part because many people find that it has a baby-like cuteness. Also, it is usually depicted reclining peacefully eating bamboo, as opposed to hunting, which adds to its image of innocence. Though giant pandas are often assumed docile, they have been known to attack humans, presumably out of irritation rather than predatory behavior.^[

African Elephant

Elephants (family: Elephantidae) are large land mammals of the order Proboscidea. There are three living species: the African Bush Elephant, the African Forest Elephant and the Asian Elephant (also known as the Indian Elephant). Other species have become extinct since the last ice age, the Mammoths being the best-known of these. They were once classified along with other thick skinned animals in a now invalid order, Pachydermata.

Elephants are the largest land animals. The elephant's gestation period is 22 months, the longest of any land animal. At birth it is common for an elephant calf to weigh 120 kilograms (260 lb). An elephant may live as long as 70 years, sometimes longer. The largest elephant ever recorded was shot in Angola in 1956. This male weighed about 12,000 kilograms (26,000 lb), with a shoulder height of 4.2 metres (14 ft), a metre (yard) taller than the average male African elephant. The smallest elephants, about the size of a calf or a large pig, were a prehistoric species that lived on the island of Crete during the Pleistocene epoch.

The elephant has appeared in cultures across the world. They are a symbol of wisdom in Asian cultures and are famed for their memory and intelligence, where they are thought to be on par with cetaceans and hominids. Aristotle once said the elephant was "the beast which passeth all others in wit and mind". The word "elephant" has its origins in the Greek ἐλέφας, meaning "ivory" or "elephant".

Healthy adult elephants have no natural predators, although lions may take calves or weak individuals. They are, however, increasingly threatened by human intrusion and poaching. Once numbering in the millions, the African elephant population has dwindled to between 470,000 and 690,000 individuals. The elephant is now a protected species worldwide, with restrictions in place on capture, domestic use, and trade in products such as ivory.

Fast and Furious: Lives of Cheetahs

The cheetah is a carnivore, eating mostly mammals under 40 kilograms (88 lb), including the Thomson's gazelle, the Grant's gazelle, the springbok and the impala. The young of larger mammals such as wildebeests and zebras are taken at times, and adults too, when the cats hunt in groups. Guineafowl and hares are also prey. While the other big cats mainly hunt by night, the cheetah is a diurnal hunter. It hunts usually either early in the morning or later in the evening when it is not so hot, but there is still enough light.

The cheetah hunts by vision rather than by scent. Prey is stalked to within 10 metres (33 ft)-30 metres (98 ft), then chased. This is usually over in less than a minute, and if the cheetah fails to make a catch quickly, it will give up. The cheetah has an average hunting success rate of around 50% - half of its chases result in failure.

Running at speeds up to 70 MPH puts a great deal of strain on the cheetah's body. When sprinting, the cheetah's body temperature becomes so high that it would be deadly to continue - this is why the cheetah is often seen resting after it has caught its prey. If it is a hard chase, it sometimes needs to rest for half an hour or more.The cheetah kills its prey by tripping it during the chase, then biting it on the underside of the throat to suffocate it, for the cheetah is not strong enough to break the necks of the four-legged prey it mainly hunts. The bite may also puncture a vital artery in the neck. Then the cheetah proceeds to devour its catch as quickly as possible before the kill is taken by stronger predators.

The diet of a cheetah is dependent upon the area in which it lives. For example, on the East African plains, its preferred prey is the Thomson's gazelle. This small antelope is shorter than the cheetah (about 58 centimetres (23 in) - 70 centimetres (28 in) tall and 70 centimetres (28 in) - 107 centimetres (42 in) long), and also cannot run faster than the cheetah (only up to 80 kilometres per hour (50 mph)), which combine to make it an appropriate prey. Cheetahs look for individuals which have strayed some distance from their group, and do not necessarily seek out old or weak ones.

Cobra vs. Rat Snake

The snake will only attack a human if provoked or in other extreme circumstances which threaten its survival. Furthermore, for a dangerously venomous snake, the cobra's strikes are quite slow when compared to the extremely rapid strikes of such species as rattlesnakes. Additionally, not all bites result in envenomation and in the case of the Cobra the amount of "blank" strikes may be quite high: in one series of recorded bites in Malaysia only 55% of strikes have included envenomation. Cobra bites are fatal in about 10% of human cases. However, as with any venomous snake, any bite from a cobra should be treated as a potentially fatal injury and medical attention should be sought immediately after the bite occurs. As with all elapids, the venom of cobras is highly neurotoxic and dangerous. Therefore, any cobra bite must be regarded as life-threatening and professional medical assistance should be immediately sought. Early symptoms of a bite include ptosis, diplopia, dysphagia, and dizziness, followed by progressive respiratory muscle weakness, ultimately requiring endotracheal intubation. Cobra venom is a postsynaptic neurotoxin. It works by stopping the acetylcholine molecules in the diaphragm muscle from interacting. Without treatment death from respiratory failure may occur as early as 30 minutes after being bitten.

Standard treatment involves the use of antivenin. Additionally, it is possible to support bite victims via mechanical ventilation, using equipment of the type generally available at hospitals. Such support should be provided until the venom is metabolised and the victim can breathe unaided. If death occurs it takes place approximately 6 to 12 hours after the cobra bite. Cause of death is respiratory failure or suffocation caused by complete paralysis of the diaphragm.

Skateboarding Dog

The dog (Canis lupus familiaris) is a domesticated subspecies of the gray wolf, a mammal of the Canidae family of the order Carnivora. The term encompasses both feral and pet varieties and is also sometimes used to describe wild canids of other subspecies or species. The domestic dog has been one of the most widely kept working and companion animals in human history, as well as being a food source in some cultures. There are estimated to be 400 million dogs in the world.

The dog has developed into hundreds of varied breeds. Height measured to the withers ranges from a few inches in the Chihuahua to a few feet in the Irish Wolfhound; color varies from white through grays (usually called blue) to black, and browns from light (tan) to dark ("red" or "chocolate") in a wide variation of patterns; and, coats can be very short to many centimeters long, from coarse hair to something akin to wool, straight or curly, or smooth. It is common for most breeds to shed this coat, however some non-shedding breeds are also popular.

Planet Sun Star Comparison

The Sun (Latin: Sol) 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, which by itself accounts for about 99.8% of the Solar System's mass. Energy from the Sun, in the form of sunlight, supports almost all life on Earth via photosynthesis, and drives the Earth's climate and weather.

The surface of the Sun consists of hydrogen (about 74% of its mass, or 92% of its volume), helium (about 24% of mass, 7% of volume), and trace quantities of other elements, including iron, nickel, oxygen, silicon, sulfur, magnesium, carbon, neon, calcium, and chromium. The Sun has a spectral class of G2V. G2 means that it has a surface temperature of approximately 5,780 K, giving it a white color that often, because of atmospheric scattering, appears yellow when seen from the surface of the Earth. This is a subtractive effect, as the preferential scattering of shorter wavelength light removes enough violet and blue light, leaving a range of frequencies that is perceived by the human eye as yellow. It is this scattering of light at the blue end of the spectrum that gives the surrounding sky its color. When the Sun is low in the sky, even more light is scattered so that the Sun appears orange or even red.

The Sun's spectrum contains lines of ionized and neutral metals as well as very weak hydrogen lines. The V (Roman five) in the spectral class indicates that the Sun, like most stars, is a main sequence star. This means that it generates its energy by nuclear fusion of hydrogen nuclei into helium. There are more than 100 million G2 class stars in our galaxy. Once regarded as a small and relatively insignificant star, the Sun is now known to be brighter than 85% of the stars in the galaxy, most of which are red dwarfs.

The Sun orbits the center of the Milky Way galaxy at a distance of approximately 26 000 or 27 000 light-years from the galactic center, moving generally in the direction of Cygnus and completing one revolution in about 225–250 million years. Its orbital speed was thought to be 220 ± 20 km/s, but a new estimate gives 251 km/s. This is equivalent to about one light-year every 1,190 years, and about one AU every 7 days. These measurements of galactic distance and speed are as accurate as we can get given our current knowledge, but may change as we learn more. Since our galaxy is moving with respect to the cosmic microwave background radiation (CMB) in the direction of Hydra with a speed of 550 km/s, the sun's resultant velocity with respect to the CMB is about 370 km/s in the direction of Crater or Leo.

Star, Planet, UFO? You decide...

A star is a massive, luminous ball of plasma. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth. Other stars are visible in the night sky, when they are not outshone by the Sun. For most of its life, a star shines due to thermonuclear fusion in its core releasing energy that traverses the star's interior and then radiates into outer space. Almost all elements heavier than hydrogen and helium were created by fusion processes in stars.

Astronomers can determine the mass, age, chemical composition and many other properties of a star by observing its spectrum, luminosity and motion through space. The total mass of a star is the principal determinant in its evolution and eventual fate. Other characteristics of a star are determined by its evolutionary history, including the diameter, rotation, movement and temperature. A plot of the temperature of many stars against their luminosities, known as a Hertzsprung-Russell diagram (H–R diagram), allows the age and evolutionary state of a star to be determined.

A star begins as a collapsing cloud of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Once the stellar core is sufficiently dense, some of the hydrogen is steadily converted into helium through the process of nuclear fusion. The remainder of the star's interior carries energy away from the core through a combination of radiative and convective processes. The star's internal pressure prevents it from collapsing further under its own gravity. Once the hydrogen fuel at the core is exhausted, those stars having at least 0.4 times the mass of the Sun expand to become a red giant, in some cases fusing heavier elements at the core or in shells around the core. The star then evolves into a degenerate form, recycling a portion of the matter into the interstellar environment, where it will form a new generation of stars with a higher proportion of heavy elements.

Binary and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution.

Moon and Planet

The Moon (Latin: Luna) is Earth's only natural satellite and the fifth largest natural 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 Moon's diameter is 3,474 km, a little more than a quarter that of the Earth. This means that the Moon's volume is about 2 percent that of Earth and the pull of gravity at its surface about 17 percent that 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).

The Moon is the only celestial body to which humans have travelled and upon which humans have landed. The first artificial object to escape Earth's gravity and pass near the Moon was the Soviet Union's Luna 1, the first artificial object to impact the lunar surface was Luna 2, and the first photographs of the normally occluded far side of the Moon were made by Luna 3, all in 1959. The first spacecraft to perform a successful lunar soft landing was Luna 9, and the first unmanned vehicle to orbit the Moon was Luna 10, both in 1966. The United States (U.S.) Apollo program achieved the only manned missions to date, resulting in six landings between 1969 and 1972. Human exploration of the Moon ceased with the conclusion of the Apollo program, although several countries have announced plans to send people or robotic spacecraft to the Moon.

Phobos, Moon of Mars

Phobos is one of the least-reflective bodies in the solar system. Spectroscopically it appears to be similar to the D-type asteroids, and is apparently of composition similar to carbonaceous chondrite material Phobos' density is too low to be solid rock, however, and it is known to have significant porosity. These results led to the suggestion that Phobos might contain a substantial reservoir of ice. Spectral observations indicate that the surface regolith layer lacks hydration,^[ but ice below the regolith is not ruled out.

Faint dust rings produced by Phobos and Deimos have long been predicted but attempts to observe these rings have, to date, failed. Recent images from Mars Global Surveyor that Phobos is covered with a layer of fine-grained regolith at least 100 metres thick; it is believed to have been created by impacts from other bodies, but it is not known how the material stuck to an object with almost no gravity.

Phobos is highly nonspherical, with dimensions of 27 × 22 × 18 km. Because of its shape alone, the gravity on its surface varies by about 210%; the tidal forces raised by Mars more than double this variation (to about 450%) because they compensate for a little more than half of Phobos' gravity at its sub- and anti-Mars poles.

Phobos is heavily cratered. The most prominent surface feature is Stickney crater, named after Asaph Hall's wife, Angeline Stickney Hall, Stickney being her maiden name. Like Mimas's crater Herschel on a smaller scale, the impact that created Stickney must have almost shattered Phobos. Many grooves and streaks also cover the oddly shaped surface. The grooves are typically less than 30 m deep, 100 to 200 m wide, and up to 20 km in length, and were originally assumed to have been the result of the same impact that created Stickney. Analysis of results from the Mars Express spacecraft, however, revealed that the grooves are not in fact radial to Stickney, but are centered on the leading apex of Phobos in its orbit (which is not far from Stickney), and must have been excavated by material ejected into space by impacts on the surface of Mars. The grooves thus formed as crater chains, and all of them fade away as the trailing apex of Phobos is approached. They have been grouped into 12 or more families of varying age, presumably representing at least 12 Martian impact events.

The unique Kaidun meteorite is thought to be a piece of Phobos, but this has been difficult to verify since little is known about the detailed composition of the moon.

In Memory of Pluto...

Pluto from Latin: Plūto, Greek: Πλούτων), formal designation (134340) Pluto, is the second-largest known dwarf planet in the Solar System (after Eris) and the tenth-largest body observed directly orbiting the Sun. Originally classified as a planet, Pluto is now considered the largest member of a distinct population called the Kuiper belt.

Like other members of the Kuiper belt, Pluto is composed primarily of rock and ice and is relatively small: approximately a fifth the mass of the Earth's moon and a third its volume. It has a highly eccentric and highly inclined orbit.

Pluto's eccentricity takes it from 30 to 49 AU (4.4–7.4 billion km) from the Sun, causing Pluto to occasionally come closer to the Sun than Neptune. Pluto and its largest moon, Charon, are often treated together as a binary system because the barycentre of their orbits does not lie within either body. The International Astronomical Union (IAU) has yet to formalise a definition for binary dwarf planets, and until it passes such a ruling, Charon is classified as a moon of Pluto.Pluto has two known smaller moons, Nix and Hydra, discovered in 2005.

From its discovery in 1930 until 2006, Pluto was considered the Solar System's ninth planet. In the late 20th and early 21st centuries, however, many objects similar to Pluto were discovered in the outer solar system, notably the scattered disc object Eris, which is 27% more massive than Pluto. On August 24, 2006 the IAU defined the term "planet" for the first time. This definition excluded Pluto, which the IAU reclassified as a member of the new category of dwarf planets along with Eris and Ceres. After the reclassification, Pluto was added to the list of minor planets and given the number 134340. A number of scientists continue to suggest that Pluto should be reclassified as a planet.

Uranus

Uranus is the seventh planet from the Sun and the third-largest and fourth-most massive planet in the solar system. It is named after the ancient Greek deity of the sky (Uranus, Οὐρανός), the father of Kronos (Saturn and grandfather of Zeus (Jupiter). Though it is visible to the naked eye like the five classical planets, it was never recognized as a planet by ancient observers due to its dimness and slow orbit.Sir William Herschel announced its discovery on March 13, 1781, expanding the known boundaries of the solar system for the first time in modern history. This was also the first discovery of a planet made using a telescope.

Uranus is similar in composition to Neptune, and both have different compositions from those of the larger gas giants Jupiter and Saturn. As such, astronomers sometimes place them in a separate category, the "ice giants". Uranus' atmosphere, while similar to Jupiter and Saturn in being composed primarily of hydrogen and helium, contains a higher proportion of "ices" such as water, ammonia and methane, along with the usual traces of hydrocarbons. It is the coldest planetary atmosphere in the Solar System, with a minimum temperature of 49 K (−224 °C). It has a complex, layered cloud structure, with water thought to make up the lowest clouds, and methane thought to make up the uppermost layer of clouds. In contrast the interior of Uranus is mainly composed of ices and rocks.

Like the other giant planets, Uranus has a ring system, a magnetosphere, and numerous moons. The Uranian system has a unique configuration among the planets because its axis of rotation is tilted sideways, nearly into the plane of its revolution about the Sun; its north and south poles lie where most other planets have their equators. Seen from Earth, Uranus' rings can sometimes appear to circle the planet like an archery target and its moons revolve around it like the hands of a clock, though in 2007 and 2008 the rings appear edge-on. In 1986, images from Voyager 2 showed Uranus as a virtually featureless planet in visible light without the cloud bands or storms associated with the other giants.However, terrestrial observers have seen signs of seasonal change and increased weather activity in recent years as Uranus approached its equinox. The wind speeds on Uranus can reach 250 meters per second (900 km/h, 560 mph).

Planet Saturn

Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn, along with Jupiter, Uranus and Neptune, is classified as a gas giant. Together, these four planets are sometimes referred to as the Jovian planets, where Jovian is the adjectival form of Jupiter.

Saturn is named after the Roman god Saturnus, equated to the Greek Kronos (the Titan father of Zeus) and the Babylonian Ninurta. Saturn's symbol represents the god's sickle (Unicode: ♄).

The planet Saturn is composed of hydrogen, with small proportions of helium and trace elements. The interior consists of a small core of rock and ice, surrounded by a thick layer of metallic hydrogen and a gaseous outer layer. The outer atmosphere is generally bland in appearance, although long-lived features can appear. Wind speeds on Saturn can reach 1800 km/h, significantly faster than those on Jupiter. Saturn has a planetary magnetic field intermediate in strength between that of Earth and the more powerful field around Jupiter.

Saturn has a prominent system of rings, consisting mostly of ice particles with a smaller amount of rocky debris and dust. Sixty known moons orbit the planet. Titan,Saturn's largest and the Solar System's second largest moon (after Jupiter's Ganymede), is larger than the planet Mercury and is the only moon in the Solar System to possess a significant atmosphere.

Universe : 4/14 : Jupiter : Giant Planet

Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is two and a half times as massive as all of the other planets in our Solar System combined. Jupiter is classified as a gas giant, along with Saturn, Uranus and Neptune. Together, these four planets are sometimes referred to as the Jovian planets, where Jovian is the adjectival form of Jupiter.

The planet was known by astronomers of ancient times and was associated with the mythology and religious beliefs of many cultures. The Romans named the planet after the Roman god Jupiter. When viewed from Earth, Jupiter can reach an apparent magnitude of −2.8, making it the third brightest object in the night sky after the Moon and Venus. (However, at certain points in its orbit, Mars can briefly exceed Jupiter's brightness.)

The planet Jupiter is primarily composed of hydrogen with a small proportion of helium; it may also have a rocky core of heavier elements under high pressure. Because of its rapid rotation, Jupiter's shape is that of an oblate spheroid (it possesses a slight but noticeable bulge around the equator). The outer atmosphere is visibly segregated into several bands at different latitudes, resulting in turbulence and storms along their interacting boundaries. A prominent result is the Great Red Spot, a giant storm that is known to have existed since at least the 17th century. Surrounding the planet is a faint planetary ring system and a powerful magnetosphere. There are also at least 63 moons, including the four large moons called the Galilean moons that were first discovered by Galileo Galilei in 1610. Ganymede, the largest of these moons, has a diameter greater than that of the planet Mercury.

Jupiter has been explored on several occasions by robotic spacecraft, most notably during the early Pioneer and Voyager flyby missions and later by the Galileo orbiter. The latest probe to visit Jupiter was the Pluto-bound New Horizons spacecraft in late February 2007. The probe used the gravity from Jupiter to increase its speed and adjust its trajectory toward Pluto, thereby saving years of travel. Future targets for exploration include the possible ice-covered liquid ocean on the Jovian moon Europa.

The Secret - Planet Earth

Earth is the third planet from the Sun. Earth is the largest of the terrestrial planets in the Solar System in diameter, mass and density. It is also referred to as the Earth, Planet Earth, the World, and Terra. Home to millions of species,including humans, Earth is the only place in the universe where life is known to exist. Scientific evidence indicates that the planet formed 4.54 billion years ago, and life appeared on its surface within a billion years. Since then, Earth's biosphere has significantly altered the atmosphere and other abiotic conditions on the planet, enabling the proliferation of aerobic organisms as well as the formation of the ozone layer which, together with Earth's magnetic field, blocks harmful radiation, permitting life on land.

Earth's outer surface is divided into several rigid segments, or tectonic plates, that gradually migrate across the surface over periods of many millions of years. About 71% of the surface is covered with salt-water oceans, the remainder consisting of continents and islands; liquid water, necessary for all known life, is not known to exist on any other planet's surface. Earth's interior remains active, with a thick layer of relatively solid mantle, a liquid outer core that generates a magnetic field, and a solid iron inner core.

Earth interacts with other objects in outer space, including the Sun and the Moon. At present, Earth orbits the Sun once for every roughly 366.26 times it rotates about its axis. This length of time is a sidereal year, which is equal to 365.26 solar days. The Earth's axis of rotation is tilted 23.4° away from the perpendicular to its orbital plane, producing seasonal variations on the planet's surface with a period of one tropical year (365.24 solar days). Earth's only known natural satellite, the Moon, which began orbiting it about 4.53 billion years ago, provides ocean tides, stabilizes the axial tilt and gradually slows the planet's rotation. A cometary bombardment during the early history of the planet played a role in the formation of the oceans. Later, asteroid impacts caused significant changes to the surface environment.

Mars

Mars pronounced is the fourth planet from the Sun in the Solar System. The planet is named after Mars, the Roman god of war. It is also referred to as the "Red Planet" because of its reddish appearance.

Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the volcanoes, valleys, deserts and polar ice caps of Earth. It is the site of Olympus Mons, the highest known mountain in the Solar System, and of Valles Marineris, the largest canyon. Furthermore, in June 2008 three articles published in Nature presented evidence of an enormous impact crater in Mars' northern hemisphere, 10 600 km long by 8 500 km wide, or roughly four times larger than the largest impact crater yet discovered, the South Pole-Aitken basin. In addition to its geographical features, Mars’ rotational period and seasonal cycles are likewise similar to those of Earth.

Until the first flyby of Mars by Mariner 4 in 1965, many speculated that there might be liquid water on the planet's surface. This was based on observations of periodic variations in light and dark patches, particularly in the polar latitudes, which looked like seas and continents, while long, dark striations were interpreted by some observers as irrigation channels for liquid water. These straight line features were later proven not to exist and were instead explained as optical illusions. Still, of all the planets in the Solar System other than Earth, Mars is the most likely to harbor liquid water, and perhaps life. Water, in the state of ice, was found by the Phoenix Mars Lander on July 31, 2008.

Mars is currently host to three functional orbiting spacecraft: Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter. This is more than any planet in the Solar System except Earth. The surface is also home to the two Mars Exploration Rovers (Spirit and Opportunity), the lander Phoenix, and several inert landers and rovers that either failed or completed missions. Geological evidence gathered by these and preceding missions suggests that Mars previously had large-scale water coverage, while observations also indicate that small geyser-like water flows have occurred during the past decade. Observations by NASA's Mars Global Surveyor show evidence that parts of the southern polar ice cap have been receding. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Martian Trojan asteroid. Mars can be seen from Earth with the naked eye. Its apparent magnitude reaches −2.9, a brightness surpassed only by Venus, the Moon, and the Sun, though most of the time Jupiter will appear brighter to the naked eye than Mars.

Venus

Venus is the second-closest planet to the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love. It is the brightest natural object in the night sky, except for the Moon, reaching an apparent magnitude of −4.6. Because Venus is an inferior planet from Earth, it never appears to venture far from the Sun: its elongation reaches a maximum of 47.8°. Venus reaches its maximum brightness shortly before sunrise or shortly after sunset, for which reason it is often called the Morning Star or the Evening Star.

Classified as a terrestrial planet, it is sometimes called Earth's "sister planet," because the two are similar in size, gravity, and bulk composition. Venus is covered with an opaque layer of highly reflective clouds of sulfuric acid, preventing its surface from being seen from space in visible light; this was a subject of great speculation until some of its secrets were revealed by planetary science in the twentieth century. Venus has the densest atmosphere of all the terrestrial planets, consisting mostly of carbon dioxide, as it has no carbon cycle to lock carbon back into rocks and surface features, nor organic life to absorb it in biomass. It has become so hot that the earth-like oceans that the young Venus is believed to have possessed have totally evaporated, leaving a dusty dry desertscape with many slab-like rocks. The best hypothesis is that the evaporated water vapor has dissociated, and with the lack of a planetary magnetic field, the hydrogen has been swept into interplanetary space by the solar wind. The atmospheric pressure at the planet's surface is 92 times that of the Earth.

Venus's surface has been mapped in detail only in the last 22 years, by Project Magellan. It shows evidence of extensive volcanism, and the sulfur in the atmosphere is taken by some experts to show that there has been some recent volcanism, but it is an enigma as to why no evidence of lava flow accompanies any of the visible caldera. There is a surprisingly low number of impact craters, demonstrating that the surface is relatively young, approximately half a billion years old. There is no evidence for plate tectonics, possibly because its crust is too strong to subduct without water to make it less viscous, and some suggest that instead Venus loses its internal heat in periodic massive resurfacing events.

The adjective Venusian is commonly used for items related to Venus, though the Latin adjective is the rarely used Venerean; the archaic Cytherean is still occasionally encountered. Venus is the only planet in the Solar System named after a female figure, although two dwarf planets— Ceres and Eris — also have feminine names.

Merkurius

Mercury is the innermost and smallest planet in the solar system, orbiting the Sun once every 88 days. Mercury is bright when viewed from Earth, ranging from −2.0 to 5.5 in apparent magnitude, but is not easily seen as its greatest angular separation from the Sun is only 28.3°. It can only be seen in morning or evening twilight. Comparatively little is known about it; the first of two spacecraft to visit Mercury was Mariner 10, which mapped only about 45% of the planet’s surface from 1974 to 1975. The second is the MESSENGER spacecraft, which mapped another 30% during its flyby of January 14, 2008. MESSENGER will make two more passes by Mercury, followed by orbital insertion in 2011, and will then survey and map the entire planet.

Mercury is similar in appearance to the Moon: It is heavily cratered, has no natural satellites and no substantial atmosphere. However, unlike the moon, it has a large iron core, which generates a magnetic field about 1% as strong as that of the Earth. It is an exceptionally dense planet due to the large relative size of its core. Surface temperatures range from about 90 to 700 K (-183 °C to 427 °C), with the subsolar point being the hottest and the bottoms of craters near the poles being the coldest.

Recorded observations of Mercury date back to at least the first millennium BC. Before the 4th century BC, Greek astronomers believed the planet to be two separate objects: one visible only at sunrise, which they called Apollo; the other visible only at sunset, which they called Hermes. The English name for the planet comes from the Romans, who named it after the Roman god Mercury, which they equated with the Greek Hermes. The astronomical symbol for Mercury is a stylized version of Hermes' caduceus.

UFO Greatest Story Ever Denied - NASA space secrets

Space is the boundless extent within which matter is physically extended and objects and events have positions relative to one another. Physical space is often conceived in three linear dimensions, although modern physicists usually consider it, with time, to be part of the boundless four-dimensional continuum known as spacetime. In mathematics spaces with different numbers of dimensions and with different underlying structures can be examined. The concept of space is considered to be of fundamental importance to an understanding of the universe although disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework.

Many of the philosophical questions arose in the 17th century, during the early development of classical mechanics. In Isaac Newton's view, space was absolute - in the sense that it existed permanently and independently of whether there were any matter in the space.Other natural philosophers, notably Gottfried Leibnizt,thought instead that space was a collection of relations between objects, given by their distance and direction from one another. In the 18th century, Immanuel Kant described space and time as elements of a systematic framework which humans use to structure their experience.

In the 19th and 20th centuries mathematicians began to examine non-Euclidean geometries, in which space can be said to be curved, rather than flat. According to Albert Einstein's theory of general relativity, space around gravitational fields deviates from Euclidean space. Experimental tests of general relativity have confirmed that non-Euclidean space provides a better model for explaining the existing laws of mechanics and optics.

Turbo Engine

A turbocharger consists of a turbine and a compressor linked by a shared axle. The turbine inlet receives exhaust gases from the engine causing the turbine wheel to rotate. This rotation drives the compressor, compressing ambient air and delivering it to the air intake manifold of the engine at higher pressure, resulting in a greater amount of the air entering the cylinder. In some instances, compressed air is routed through an intercooler before introduction to the intake manifold.

The objective of a turbocharger is the same as a supercharger; to improve upon the size-to-output efficiency of an engine by solving one of its cardinal limitations. A naturally aspirated automobile engine uses only the downward stroke of a piston to create an area of low pressure in order to draw air into the cylinder through the intake valves. Because the pressure in the atmosphere is no more than approximately 14.7 psi, there ultimately will be a limit to the pressure difference across the intake valves and thus the amount of airflow entering the combustion chamber. This ability to fill the cylinder with air is its volumetric efficiency. Because the turbocharger increases the pressure at the point where air is entering the cylinder, a greater mass of air will be forced in as the inlet manifold pressure increases. The additional air makes it possible to add more fuel, increasing the power and torque output of the engine.

Because the pressure in the cylinder must not go too high to avoid detonation and physical damage, the intake pressure must be controlled by controlling the rotational speed of the turbocharger. The control function is performed by a wastegate, which routes some of the exhaust flow away from the exhaust turbine. This controls shaft speed and regulates air pressure in the intake manifold.

The application of a compressor to increase pressure at the point of cylinder air intake is often referred to as forced induction. Centrifugal superchargers compress air in the same fashion as a turbocharger. However, the energy to spin the supercharger is taken from the rotating output energy of the engine's crankshaft as opposed to normally exhausted gas from the engine. Superchargers use output energy from an engine to achieve a net gain, which must be provided from some of the engine's total output. Turbochargers, on the other hand, convert some of the piston engine's exhaust into useful work. This energy would otherwise be wasted out the exhaust. This means that a turbocharger is a more efficient use of the heat energy obtained from the fuel than a supercharger

Jet Engine

A jet engine is a reaction engine that discharges a fast moving jet of fluid to generate thrust in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets and pump-jets. In general, most jet engines are internal combustion engines but non-combusting forms also exist.

In common usage, the term 'jet engine' generally refers to a gas turbine driven internal combustion engine, an engine with a rotary compressor powered by a turbine ("Brayton cycle"), with the leftover power providing thrust via a propelling nozzle. These types of jet engines are primarily used by jet aircraft for long distance travel. The early jet aircraft used turbojet engines which were relatively inefficient for subsonic flight. Modern subsonic jet aircraft usually use high-bypass turbofan engines which help give high speeds as well as, over long distances, giving better fuel efficiency than many other forms of transport.

About 7.2% of the oil used in 2004 was ultimately consumed by jet engines In 2007, the cost of jet fuel, while highly variable from one airline to another, averaged 26.5% of total operating costs, making it the single largest operating expense for most airlines.

Harley Drag Race Engine

Two-cylinder motorcycles are called "twins." The three most common arrangements are

1. The V-twin where the cylinders form a "V" around the crankshaft, which is oriented transversely (i.e., perpendicular to the direction of travel).
2. The inline twin or straight-two which is common in classic British motorcycles and Japanese motorcycles. It is known as a parallel twin when the cylinders share a common cranck pin. In this design the cylinders are side by side vertically above the crankcase. If not vertical they are generally nearly so in order to maximize airflow cooling.
3. The opposed twin in which the cylinders protrude sideways into the cooling air stream.

The angle in the V-twins varies from around 45 degrees to 90 degrees. Typical of the former are the Harley Davidson and Vincent engines which because of their firing order tend to vibrate more. Ducati and Moto-Guzi make V-twins with cylinders arranged at a 90 degree angle to quell primary vibrations. Some Moto Guzzi motorcycles have V-twins oriented transversely: one cylinder to the left, one to the right.

How a Car Engine Works (Internal Combustion Engine)

The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. This exothermic reaction creates gases at high temperature and pressure, which are permitted to expand. Internal combustion engines are defined by the useful work that is performed by the expanding hot gases acting directly to cause the movement of solid parts of the engine.

The term Internal Combustion Engine (ICE) is often used to refer to an engine in which combustion is intermittent, such as a Wankel engine or a reciprocating piston engine in which there is controlled movement of pistons, cranks, cams, or rods. However, continuous combustion engines such as jet engines, most rockets, and many gas turbines are also classified as types of internal combustion engines. This contrasts with external combustion engines such as steam engines and Stirling engines that use a separate combustion chamber to heat a separate working fluid—which then in turn does work. For example, by moving a piston or a turbine.

A huge number of different designs for internal combustion engines exist, each with different strengths and weaknesses. Although they're used for many different purposes, internal combustion engines particularly see use in mobile applications such as cars, aircraft, and even handheld applications: all where their ability to use an energy-dense fuel (especially fossil fuels) to deliver a high power-to-weight ratio

Search Engine Optimazation

Search engine optimization (SEO also search optimization) is the process of editing and organizing the content on a webpage or across a website to increase its potential relevance to specific keywords on specific search engines and importantly ensuring that external links to the site are correctly titled and in abundance. This is done with the aim of achieving a higher organic search listing and thus increasing the volume of traffic from search engines.

SEO is one of the key Web Marketing activities and can target different kinds of searches, including image search, local search, and industry-specific vertical search engines.

SEO considers how search engines work and what people search for. Optimizing a website primarily involves editing its content and HTML coding to both increase its relevance to specific keywords and to remove barriers to the indexing activities of search engines. Sometimes a site's structure (the relationships between its content) must be altered too. Because of this it is, from a client's perspective, always better to incorporate Search Engine Optimization when a website is being developed than to try and retroactively apply it.

Another class of techniques, known as black hat SEO or Spamdexing, use methods such as link farms and keyword stuffing that degrade both the relevance of search results and the user-experience of search engines. Search engines look for sites that employ these techniques in order to remove them from their indices.

The term 'Search engine friendly' refers to a website that has been search optimised.

Bullfrog Ballet

The bullfrog is the largest of the North American ranids. Reaching a body length of 20 centimetres (7.9 in), bullfrogs weigh up to 750 grams (1.7 lb). Females are typically larger than males. Males have a tympanum twice the diameter of the eye, and a yellow throat. Female tympanum diameter is the same as that of the eye. Bullfrogs are generally varying shades of green or brown. The head is usually mostly green. The body varies from olive to brown, and may be darkly blotched or spotted. The hindlimbs may be darkly banded.

Similar species include the green frog (Rana clamitans) and pig frog (Rana grylio). The bullfrog may be distinguished from the green frog by the bullfrog's lack of dorsolateral folds, prominent, seam-like skin folds that course down the sides of the back of the green frog. The pig frog has a more pointed snout and its fourth toe (counting medially to laterally) is webbed whereas that of the bullfrog extends un-webbed beyond the other toes.

The adult bullfrog skeleton is representative of tetrapod vertebrates, comprised of an axial skeleton (skull and vertebrae) and an appendicular skeleton (pectoral girdle and forelimbs, pelvic girdle and hindlimbs). Ranids, however, lack ribs. The pronounced pair of dorsal humps in the back of ranid frogs are the ends of the pelvic ilia, homologues of the human hips.

The bullfrog skull is highly fenestrated. The orbits open ventrally through the roof of the mouth to accommodate eye retraction during locomotion and swallowing. The skull bears a continuous row of tiny teeth on the maxilla and premaxilla and a pair of small vomerine teeth on the palate. The mandible is toothless.

The bullfrog nervous system consists of a brain, spinal cord, and peripheral nerves including cranial nerves, spinal nerves, and sympathetic nerves serving organs such as the heart, gastrointestinal tract, kidneys, gonads.

Global Warming

Global warming is the increase in the average measured temperature of the Earth's near-surface air and oceans since the mid-20th century, and its projected continuation.

The average global air temperature near the Earth's surface increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the 100 years ending in 2005. The Intergovernmental Panel on Climate Change (IPCC) concludes "most of the observed increase in globally averaged temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic (man-made) greenhouse gas concentrations" via an enhanced greenhouse effect. Natural phenomena such as solar variation combined with volcanoes probably had a small warming effect from pre-industrial times to 1950 and a small cooling effect from 1950 onward.

These basic conclusions have been endorsed by at least 30 scientific societies and academies of science including all of the national academies of science of the major industrialized countries. While individual scientists have voiced disagreement with some findings of the IPCC, the overwhelming majority of scientists working on climate change agree with the IPCC's main conclusions.

Climate model projections summarized by the IPCC indicate that average global surface temperature will likely rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century. This range of values results from the use of differing scenarios of future greenhouse gas emissions as well as models with differing climate sensitivity. Although most studies focus on the period up to 2100, warming and sea level rise are expected to continue for more than a thousand years even if greenhouse gas levels are stabilized. The delay in reaching equilibrium is a result of the large heat capacity of the oceans.

Increasing global temperature is expected to cause sea levels to rise, an increase in the intensity of extreme weather events, and significant changes to the amount and pattern of precipitation, likely leading to an expanse of tropical areas and increased pace of desertification. Other expected effects of global warming include changes in agricultural yields, modifications of trade routes, glacier retreat, mass species extinctions and increases in the ranges of disease vectors.

Remaining scientific uncertainties include the amount of warming expected in the future, and how warming and related changes will vary from region to region around the globe. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions, but there is ongoing political and public debate worldwide regarding what, if any, action should be taken to reduce or reverse future warming or to adapt to its expected consequences.

Warship

A warship is a ship that is built and primarily intended for combat. Warships are usually built in a completely different way than merchant ships. As well as being armed, warships are designed to withstand damage and are usually faster and more maneuverable than merchant ships. Unlike a merchant ship, a warship typically only carries weapons, ammunition and supplies for its own crew (rather than merchant cargo). Warships usually belong to a navy, though they have sometimes been operated by individuals or companies.

In wartime, the distinction between warships and merchant ships is often blurred. In war, merchant ships are often armed and used as auxiliary warships, such as the Q-ships of World War I and the armed merchant cruisers of World War II. Until the 17th century it was common for merchant ships to be pressed into naval service and not unusual for more than half a fleet to be composed of merchant ships. Until the threat of piracy subsided in the 19th century, it was normal practice to arm larger merchant ships such as Galleons. Warships have also often been used as troop carriers or supply ships, such as by the French Navy in the 18th century or the Japanese Navy during World War II.

Cat Fight

The cat (Felis catus), also known as the domestic cat or house cat to distinguish it from other felines, is a small predatory carnivorous species of crepuscular mammal that is valued by humans for its companionship and its ability to hunt vermin, snakes and scorpions. It has been associated with humans for at least 9,500 years.

A skilled predator, the cat is known to hunt over 1,000 species for food.It can be trained to obey simple commands. Individual cats have also been known to learn on their own to manipulate simple mechanisms, such as doorknobs. Cats use a variety of vocalizations and types of body language for communication, including meowing, purring, hissing, growling, squeaking, chirping, clicking, and grunting. With 69 million of them present in American homes, cats are the most or the second most popular pets in that country. Cats also may be the most popular pet in the world, with over 600 million in homes all over the world. They are also bred and shown as registered pedigree pets. This hobby is known as the "Cat Fancy".

Until recently the cat was commonly believed to have been domesticated in ancient Egypt, where it was a cult animal. However a 2007 study found that all house cats are probably descended from a group of as few as five self-domesticating African Wildcats Felis silvestris lybica circa 8000 BC, in the Near East.

The Miracle in Human Brain

The human brain weighs about three pounds, or 1.5 kg. In its natural state it is very soft, having approximately the consistency of pudding, although surrounded by leathery membranes and interspersed with stringy blood vessels. When alive it is pinkish on the outside, and mostly white on the inside, with subtle variations in color. Anatomists, in order to make it solid enough to work with, usually apply fixatives that give the tissue a rubbery texture and grayish color. The brains of other species have generally similar properties, but smaller sizes in relation to the body.

The largest portion of the human brain comprises the cerebral hemispheres, situated at the top and covered with a very convoluted "cortex". Underneath the cerebrum lies the brainstem, appearing somewhat like a stalk on which the cerebrum is mounted. At the back of the brain, beneath the cerebrum and behind the brainstem, is the cerebellum, a structure with a horizontally furrowed surface that makes it look different from anything else. These are the main structures visible from the outside, but a great deal more lies hidden below the surface. In other mammals, the same structures are present, but the cerebrum is not so large in relation to the brain as a whole. As a rule, the smaller the cerebrum, the less convoluted the cortex. The cortex of a rat or mouse is almost completely smooth. The cortex of a dolphin or whale, on the other hand, is substantially more convoluted than the cortex of a human.

In vertebrates, the brain is surrounded by connective tissues called meninges, a system of membranes that separate the skull from the brain. This three-layered covering is composed of (from the outside in) the dura mater ("hard mother"), arachnoid mater ("spidery mother"), and pia mater ("soft mother"). The arachnoid and pia are physically connected and thus often considered as a single layer, the pia-arachnoid. Below the arachnoid is the subarachnoid space which contains cerebrospinal fluid, a substance that protects the nervous system. Blood vessels enter the central nervous system through the perivascular space above the pia mater. The cells in the blood vessel walls are joined tightly, forming the blood-brain barrier which protects the brain from toxins that might enter through the blood. The brain is bathed in cerebrospinal fluid (CSF), which circulates in the narrow spaces between cells, and through cavities called ventricles. CSF is important both metabolically and mechanically: it provides neutrients to the brain, supports it, and cushions it against shocks.

The cortex is the part of the brain that most strongly distinguishes mammals from other vertebrates, primates from other mammals, and humans from other primates. In non-mammalian vertebrates, the surface of the cerebrum is lined with a comparatively simple layered structure called the pallium. In mammals, the pallium evolves into a complex 6-layered structure called neocortex. In primates, the neocortex is greatly enlarged in comparison to its size in non-primates, especially the part called the frontal lobes. In humans, this enlargement of the frontal lobes is taken to an extreme, and other parts of the cortex also become quite large and complex.

In other vertebrates—fish, amphibians, reptiles, birds—the same basic structures are present, but may be reshaped to give a dramatically different appearance. In non-vertebrates—insects, molluscs—the components and their arrangements differ so greatly that it is impossible to make meaningful comparisons except on the basis of genetics. In all, three groups of animals have notably complex brains: the arthropods (insects, crustaceans, arachnids, and others), the cephalopods (octopuses, squids, and similar mollusks), and the craniates (vertebrates and hagfish).^[1] The brains of arthropods and cephalopods arise from twin parallel nerve cords that extend through the body of the animal. Arthropods have a central brain with three divisions and large optical lobes behind each eye for visual processing.^[1] Cephalopods have the largest brains of any invertebrates. The brain of the octopus in particular is very highly developed, apparently comparable in complexity to the brain of a bird or reptile.

The Five Major Class of Chemical Reactions

A chemical reaction is a process that always results in the interconversion of chemical substances.^[1] The substance or substances initially involved in a chemical reaction are called reactants. Chemical reactions are usually characterized by a chemical change, and they yield one or more products which are, in general, different from the reactants. Classically, chemical reactions encompass changes that strictly involve the motion of electrons in the forming and breaking of chemical bonds, although the general concept of a chemical reaction, in particular the notion of a chemical equation, is applicable to transformations of elementary particles, as well as nuclear reactions.

Different chemical reactions are used in combinations in chemical synthesis in order to get a desired product. In biochemistry series of chemical reactions catalyzed by enzymes form metabolic pathways, by which syntheses and decompositions ordinarily impossible in conditions within a cell are performed.

Presentacion windows vista

Windows Vista (pronounced /ˈvɪstə/) is a line of operating systems developed by Microsoft for use on personal computers, including home and business desktops, laptops, Tablet PCs and media center PCs. Prior to its announcement on July 22, 2005, Windows Vista was known by its codename Longhorn.^[3] Development was completed on November 8, 2006; over the following three months it was released in stages to computer hardware and software manufacturers, business customers, and retail channels. On January 30, 2007, it was released worldwide,^[4] and was made available for purchase and download from Microsoft's website.^[5] The release of Windows Vista came more than five years after the introduction of its predecessor, Windows XP, the longest time span between successive releases of Microsoft Windows.

Windows Vista contains many changes and new features, including an updated graphical user interface and visual style dubbed Windows Aero, improved searching features, new multimedia creation tools such as Windows DVD Maker, and redesigned networking, audio, print, and display sub-systems. Vista also aims to increase the level of communication between machines on a home network, using peer-to-peer technology to simplify sharing files and digital media between computers and devices. Windows Vista includes version 3.0 of the .NET Framework, which aims to make it significantly easier for software developers to write applications than with the traditional Windows API.

Microsoft's primary stated objective with Windows Vista, however, has been to improve the state of security in the Windows operating system.^[6] One common criticism of Windows XP and its predecessors has been their commonly exploited security vulnerabilities and overall susceptibility to malware, viruses and buffer overflows. In light of this, Microsoft chairman Bill Gates announced in early 2002 a company-wide "Trustworthy Computing initiative" which aims to incorporate security work into every aspect of software development at the company. Microsoft stated that it prioritized improving the security of Windows XP and Windows Server 2003 above finishing Windows Vista, thus delaying its completion.^[7]

While these new features and security improvements have garnered positive reviews, Vista has also been the target of much criticism and negative press. Criticism of Windows Vista has targeted high system requirements, its more restrictive licensing terms, the inclusion of a number of new digital rights management technologies aimed at restricting the copying of protected digital media, lack of compatibility with certain pre-Vista hardware and software, and the number of authorization prompts for User Account Control. As a result of these and other issues, Windows Vista has seen adoption and satisfaction rates lower than Windows XP.^[8]

TUTORIAL: install Ubuntu Linux 7.10

Ubuntu (IPA: [uːˈbuːntuː] in English,^[2] [ùɓúntú] in Zulu) is a free computer operating system based on the Linux kernel. Its name comes from the Zulu word ubuntu, loosely translated as "humanity" or "A person is a person only through other people". Ubuntu's goals include providing an up-to-date, stable operating system for the average user, with a strong focus on usability and ease of installation. Ubuntu has been rated as the most popular Linux distribution, claiming approximately 30% of desktop Linux installations in a survey.

Ubuntu is free and open source, meaning that not only is it distributed without charge, but it may also be freely improved upon. Ubuntu is sponsored by Canonical Ltd, which is owned by South African entrepreneur Mark Shuttleworth. Instead of selling Ubuntu itself, Canonical makes money by selling paid support for Ubuntu. By keeping Ubuntu free and open Canonical is able to leverage the talents of outside developers willing to contribute rather than having to do all development within the company itself.

Kubuntu and Xubuntu are official subprojects of the Ubuntu project, aiming to bring the KDE and Xfce desktop environments, respectively, to the Ubuntu core (by default Ubuntu uses GNOME for its desktop environment). Edubuntu is an official subproject designed for school environments and should be equally suitable for children to use at home. Gobuntu is an official subproject that is aimed at adhering strictly to the Free Software Foundation's Four Freedoms.^[8] Ubuntu JeOS (pronounced "Juice") is the newest official subproject. JeOS is a concept for what an operating system should look like in the context of a virtual appliance.^[9]

Ubuntu releases new versions every six months, and supports those releases for 18 months with daily security fixes and patches to critical bugs. LTS (Long Term Support) releases, which occur every two years,^[10] are supported for three years for desktops and five years for servers.^[11] The most recent version, Ubuntu 8.04 LTS (Hardy Heron), was released on April 24, 2008, although an update, Ubuntu 8.04.1 has been released. The next version will be 8.10 (Intrepid Ibex) and is scheduled for release on 30th October 2008.^[12]

M1 Abrams Tank

armoured fighting vehicle designed for front-line combat which combines operational mobility and tactical offensive and defensive capabilities. Firepower is normally provided by a large-calibre main gun in a rotating turret and secondary machine guns, while heavy armour and all-terrain mobility provide protection for the tank and its crew, allowing it to perform all primary tasks of the armoured troops on the battlefield.^[1]

Tanks were first manufactured during World War I in an effort to break the bloody deadlock of trench warfare. The British Army was the first to field a vehicle that combined three key characteristics: mobility over barbed wire and rough terrain, armour to withstand small arms fire and shrapnel and the firepower required to supreme or destroy machine gun nests and pillboxes. Despite some success and a significant psychological effect on the German infantry, "the tank in 1918 was not a war-winning weapon."^[2]

Interwar developments culminated in the blitzkrieg employed by the German Wehrmacht during World War II and the contribution of the panzers to this doctrine. Hard lessons learned by the Allies during World War II cemented the reputation of the tank, appropriately employed in combined arms forces, as "indispensable to success in both tactical and strategic terms."^[3] Today, tanks seldom operate alone, being organized into armoured units and operating in combined-arms formations. Despite their apparent invulnerability, without support tanks are vulnerable to anti-tank artillery, helicopters and aircraft, enemy tanks, anti-tank and improvised mines, and (at close range or in urban environments) infantry.^[4]

Due to its formidable capabilities and versatility the battle tank is generally considered a key component of modern armies,^[5] but recent thinking has challenged the need for such powerful and expensive weaponry in a period characterized by unconventional and asymmetric warfare.^[6] Ongoing research and development attempts to equip the tank to meet the challenges of the 21st century.