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Solar system

            Our solar system is formed by the Sun and another eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Each planet can have moons or rings. Beside the planets, the system also contains asteroids, located mainly in two regions, the Asteroid Belt, between Mars and Jupiter and the Kuiper Belt, near the orbit of Pluto and comets, which are concentrated in the Oort Cloud, region surrounding our solar system at a distance of 30 to 100 AU from the Sun, composed of dust and 1 trillion (estimate) nuclei of comets that occasionally are launched toward the sun due to some disturbance in its orbit. When an asteroid moves into a collision course to Earth, it is called meteoroids.

http://www.planetario.ufrgs.br/sistemasolar.GIF

Curiosities

• The failures of Kirkwood

            The gravitational force of Jupiter still affects the belt of asteroids. Its enormous mass interfere asteroids and creates large gaps in the main belt known as the failures of Kirkwood.
            There are also two clouds of asteroids in front and behind the path of Jupiter, known as the Jupiter Trojans, which act as a sort of bodyguard around the globe. Two similar groups are found along the orbit of Mars called the Mars Trojans.

• Moons against moons

            Currently, we know 13 moons of Neptune; the largest of them is called Triton and measure 2700 km of diameter. Triton and other 3 moons orbit the planet in the opposite direction of the other 9 moons.

• If the sun no longer exists:

            The temperature of the Earth would be about -270 °C, and life, color, wind and others (because every form of life requires energy) would not exist.
            The human being does not use solar energy directly, but eat plants that transform that energy into chemical energy (sugars) and animals that turn into fat, another form of chemical energy.
            We would not have coal, oil and natural gas, which are products of the capture and storage of sunlight in plants, algae and prehistoric animals that existed millions of years ago.
            Evaporation of water would stop, and it is also very important because without it we would not have the rains and the humidity of the air would be minimal (almost zero).
            The winds would not exist, because the uneven heating of the earth's atmosphere by the sun causes the appearance of regions with different air pressures. The regions that have high pressure air tend to move to regions of low pressure, thus creating the winds.

• Eclipses

            The total eclipse occurs when the Sun is completely obscured by the Moon, this occurs when the Sun, the New Moon and Earth are perfectly aligned.

http://www.redorbit.com/user_files/images/space/eclipses/eclipse_solar.jpg

            Due to the elliptical path of the Moon around the Earth, there are times when the visual size of the Moon is smaller than the Sun. When the total eclipse occurs in these conditions, we can see a ring of light around the moon, and the annular eclipse of the Sun happens.

http://www.asaaf.org/eclipseanular/imagenes-eclipseanular/eclipse31.jpg

            The partial eclipse of the sun occurs when the Sun, New Moon and Earth are not perfectly aligned or when the Moon hides only part of the Sun.

http://www.estadao.com.br/fotos/eclip-int.jpg

            The eclipse of the Moon may be partial or total. It occurs when the Full Moon enters the umbra of the Earth.

http://www.devin.com.br/wp-content/uploads/2008/08/eclipse-lunar.jpg

• Comet may have been the cause of the extinction of dinosaurs

            Some scientists believe that 65 million years ago, a comet crashed on the Caribbean Sea. At that time our ancestors (mammals) were fortunate to be small enough to resist the days of darkness, cold and little food that followed. All other living beings with more than 15 kg failed to survive, including the dinosaurs.

• The earth is bombarded by meteors all the time

            Twice a week, approximately, a meteor with the size of a shoebox, penetrate the Earth's atmosphere and explode with the force of an atomic bomb. Fortunately, due to friction with our atmosphere these meteors vaporize more than 8 km from the ground. When a piece of meteor is not destroyed and reach the surface, it is called a meteorite. Millions of meteors hit the Earth every day, but most of them have the size of a grain of sand.

• We always see the same face of the Moon

            Seen from Earth, the satellite shows stages, but shows the same face, which generated many speculations about the dark side of the Moon that in fact is illuminated when in the period of New Moon. That happens because their period of rotation is equal to the period of translation.

• Uranus has been a star?

            The astronomer John Flamsteed discovered Uranus in 1690, but he catalogued it as a star called Tauri. In 1781 William Herschel discovered it as a planet, and gave the name of "the Georgium Sidus" (the Georgian Planet) as a gift to the English King George III, but after your name is changed to Uranus, that was the father of Saturn in Greco-Roman mythology. This name was proposed by the German astronomer Johann Elert Bode around 1850.

• The strange movements of Uranus

            We can see that instead of rotating around the Sun, it seems that Uranus is rolling. It also has the retrograde motion (movement that goes back). Thanks to the tilting of Uranus, the poles receive more light that the central areas.

• A planet discovered by mathematical calculations

            Neptune was the first planet discovered by calculations and in 1846 was found by powerful telescopes. After the discovery of Uranus, the astronomer Alexis Bouvard in 1820 noted that its orbit not followed the path established by the laws of celestial mechanics and therefore realized that after there was a new planet Uranus. This led the English astronomer John C. Adams mathematically determine the location of Neptune, and some months after the French astronomer Urbain Le Verrier got the same results. Today, we know that the two astronomers find the wrong location for a short, but even with those calculations can be found the eighth planet.

The Wonderful World of Astronomy - ThinkQuest
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2009