The Planets Explained
There are many planets that make up our solar system - we here at VideoJug give you a brief overview in our film The Planets Explained.
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Step 1:
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The planets
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Our Solar system is in a Galaxy very similar to this one about ¾ of the way out from the centre. From the Earth our Galaxy can be seen stretching across the sky, we call it the Milky Way.
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Step 2:
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The Sun
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Our Sun is a medium sized, middle aged star amongst about 6 Billion other stars in the Galaxy. It has a surface temperature of over 6,000°C. The dark areas are called sunspots; these are magnetic storms coming up from the interior. The Sun is not 'burning' but instead it is a Nuclear reaction turning hydrogen into helium. And with x-ray it looks very violent indeed. But all life on Earth depends on The Sun.
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Step 3:
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Mercury
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Coming out from the Sun, the first Planet is Mercury, the Smallest of all the Planets. Mercury is not much bigger than our Moon and like the Moon it is covered in deep impact craters from meteorites. The surface is so hot it could melt lead. In ancient times Mercury was known as the messenger of the Gods because it moves so quickly. It goes around the Sun once every 88 days.
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Step 4:
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Venus
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Next is Venus. Because it is only visible either just after Sunset or before Sunrise it is often known as the Evening star or morning Star. It is the brightest of all the Planets that we can see in the sky. Venus is very similar in size to the Earth, but it is covered in a thick blanket of cloud. However, using radar we are able to see right through the clouds to the surface of the planet. These clouds are causing a runaway greenhouse effect making the temperature on the surface climb to over 400°C, hotter even than Mercury.
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Step 5:
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Earth
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Earth, the blue Planet and our home. 153 million km from the Sun, 4/5ths of it are covered in water. It was not until the 16th century that people realised that the Earth was actually a planet! From space the continents are easily visible; this is the straight of Gibraltar. It is the only Planet that we know of that has life on it...up to now!
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Step 6:
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The Moon
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The Moon is our nearest neighbour in space at 384,000km. The moon goes around Earth every 28 days but it always keeps the same face pointed towards us. The dark areas are called seas; they are not real seas of water, just areas of a different coloured material than the surrounding areas. The surface is pockmarked with thousands of craters caused mostly from impacts from meteorites over millions of years. There are also many high mountain ranges, some stretching for hundreds of miles. Between 1969 and 1972, 12 American astronauts landed on the Moon. The first two were Neil Armstrong and 'Buzz' Aldrin. Some of the later astronauts even took a car along with them to go exploring.
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Step 7:
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Mars
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Mars, the red Planet. Mars has polar ice caps made from frozen carbon dioxide. These grow and shrink throughout the Martian seasons. There are very high winds on Mars that create dust storms, sometimes covering the whole Planet. The surface is coloured red and is very barren and because of the winds it is much eroded. For many years it was believed that Mars had life on it. NASA has sent probes to Mars to search for life, but without much luck unfortunately. Mars has two, tiny, 'potato' shaped moons called Phobos and Deimos.
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Step 8:
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Jupiter
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Jupiter is the largest Planet in the solar system, but unlike the Earth it is not made from rock. It is a 'gas giant' made mostly from Hydrogen and Helium. It is so big it could easily swallow all the other Planets. Despite its size Jupiter spins very quickly, a day on Jupiter lasts just 10 hours. Jupiter has over 60 moons, the four largest moons were discovered by the Italian Astronomer Galileo with the very first telescope in the year 1610. The ‘great red spot' is believed to be a giant storm that has been raging in the upper clouds for over 300 years; it is 10 times bigger than the Earth!
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Step 9:
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Saturn
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Saturn is the second largest Planet. Like Jupiter, Saturn too is a gas giant with no rocky surface, what we see is merely the tops of the clouds. The most striking thing about Saturn is its ring system. They are not solid but split into many different rings, and while being many hundreds of thousands km across they are less than 100 meters in thickness. The rings are made from millions of small pieces of rock and ice orbiting around the planet. Saturn also has many moons, the largest of which, Titan, is the biggest in the solar system.
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Step 10:
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Uranus
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Uranus is the seventh planet from the Sun and is the third largest in the solar system. It was discovered by William Herschel in 1781. Uranus is a very odd Planet; it is tipped over onto its side and rolls around the Sun keeping one pole always pointing at the Sun, while the other pole is in constant darkness. Recently it was discovered that it too had a ring system, not quite as good as Saturn's, it was probably formed by a moon breaking up into millions of pieces.
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Step 11:
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Neptune
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Neptune is the fourth largest planet in the solar system. It is 4 ½ billion km from the Sun. It was not discovered until 1846. It has eight moons, but only the biggest one, Triton, can be seen from Earth. Neptune's atmosphere is mostly hydrogen and helium gases. Methane gas in the upper part of the planet's atmosphere gives Neptune a vivid blue colour. Neptune was visited in 1989 by a NASA spacecraft called Voyager 2. Almost everything we know about Neptune comes from this mission.
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Step 12:
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Pluto
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Finally; tiny Pluto and its companion Charon. Pluto was only discovered in 1930 by American astronomer Clyde Tomburgh. In 2006 Pluto was down graded, it is no longer considered a planet. It is too small and its orbit so erratic that the International Astronomical Union agreed that it should now be called a planetoid or minor planet. Hats off for poor Pluto!
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Step 13:
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Comets
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Outside the orbit of Pluto live the Comets. These are giant 'dirty snowballs', made of rock and ice. Occasionally they come very close to the Sun when they begin to evaporate and can sometimes produce very spectacular tails stretching for millions of miles into space. It is believed that it was the comets that first brought the beginnings of life to Earth.