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The Earth: From space, the Earth looks small with a thin, fragile layer of atmosphere, while the features that distinguish it from the other planets are its blue waters, brown and green land masses, and white clouds set against a black background. Earth is the 3rd planet from the Sun at a distance of about 150 million kilometres. It takes 365.256 days for the Earth to make a revolution around the Sun and 23.9345 hours for the Earth to make a rotation on its own axis. The Earth travels at the speed of 108,000 kilometres per hour. It has a diameter of 12,756 kilometres, only a few hundred kilometres larger than that of Venus. Our atmosphere is composed of 78 percent nitrogen, 21 percent oxygen, and 1 percent other gases. Earth is the only planet in the solar system known to support life. Our planet's rapid spin and liquid nickel-iron core allow for an extensive magnetic field, which along with the atmosphere, shields us from nearly all of the harmful radiation coming from the Sun and other stars, as well as meteors and comets that mostly burn up before they can strike the surface. Jupiter: Jupiter is the fifth and largest planet in the solar system. If Jupiter were hollow, more than one thousand Earths could fit inside. It also contains more matter than all of the other planets combined. It has a mass of 1.9 x 1027 km, a diameter of 142,800 kilometres, and a distance of 778,330,000 km from the Sun. There is a ring system, but it is very faint and is totally invisible from Earth. The atmosphere is very deep, probably covering the whole planet, and is somewhat like the Sun. It is composed mainly of hydrogen and helium, with small amounts of methane, ammonia, water vapour, and other compounds. At great depths within Jupiter, the pressure is so great that the hydrogen atoms are broken up and the electrons are freed so that the resulting atoms consist of bare protons. This produces a state in which the hydrogen becomes metallic. Mars: Mars is the fourth planet from the Sun and is commonly referred to as the Red Planet. The rocks, soil and sky have a red or pink colour. The average temperature on Mars is -63° C, with a maximum temperature of 20° C, and a minimum of -140° C. Its mass is 6.421 x 1023 kg with a diameter of 6794.4 km. The atmosphere of Mars is quite different from that on Earth. It is composed mainly of carbon dioxide with small amounts of other gases. The six most common components of the atmosphere are: 95.320% of carbon dioxide, 2.7% of Nitrogen, 1.6% of Argon, 0.13% of Oxygen, 0.03% of water, and 0.00025% of Neon. The Black Hole:   A black hole is the most powerful and mysterious phenomenon in the universe. The gravity within a black hole is so intense that not even light, the fastest object we know of, can escape its force. A black hole is so dense that 100 million suns would be compressed to a globe 6 million kilometers in diameter. Our sun is only 1,390,000 kilometers in diameter. You get the picture. It is even said that there is a super-massive black hole at the center of every galaxy. These black holes have a single point called a “singularity” that apparently has an infinite mass. Therefore a black hole could technically swallow an entire solar system in seconds if the horizon could expand that quickly. These giant, destructive, mysterious beasts are the most complex puzzles in the universe, and are still being researched in more detail. The Milky Way:   The Milky Way is the galaxy which is the home of our Solar System as well as at least 400 billion other solar systems with their stars and planets, and thousands of clusters and nebulae. As a galaxy, the Milky Way is actually a giant, as its mass is probably between 750 billion and one trillion solar systems, and its diameter is about 100,000 light years. The distribution of hydrogen clouds in the galaxy has revealed that the Milky Way is in the shape of a spiral. The band of light that we call the Milky Way is actually the flat surface of the disk of our galaxy. There is a spherical component to the Milky Way galaxy, which contains very old stars (in round clusters too). Again, due to the massive size of our galaxy, light would take about 100,000 years to cross from one end of it to another. The Sun:   The Sun is the most prominent feature in our solar system (middle-age, average-size star). It is the largest object and contains approximately 98% of the total solar system mass. 109 Earths would be required to fit across the Sun's disk, and its interior could hold over 1.3 million Earths. The Sun's outer visible layer is called the photosphere and has a temperature of 6,000°C. This layer has a spotty appearance due to the unstable eruptions of energy at the surface. Solar energy is created deep within the core of the Sun. It is here that the temperature (15,000,000° C) and pressure (340 billion times Earth's air pressure at sea level) is so intense that nuclear reactions take place. This reaction causes a series of double Hydrogen atoms to fuse and create single Helium atoms. A single Hydrogen atom is about 0.7% less massive than the combined Helium molecule. The difference in mass is released as energy, and is carried to the surface of the Sun, where it is released as light and heat. Energy generated in the Sun's core takes a million years to reach its surface. Every second, 700 million tons of hydrogen is converted into helium ashes. In this process, 5 million tons of pure energy is released, so as time goes on, the Sun is becoming lighter. The Hubble Space Telescope:   Hubble orbits 600 kilometers above Earth’s surface, working around the clock to unlock the secrets of the Universe. It uses excellent pointing precision, powerful optics, and state-of-the-art instruments to provide stunning views of the Universe that cannot be made using ground-based telescopes or other satellites. Hubble whirls around the Earth at 5 miles per second or 18,000 mph, while completing one full orbit every 97 minutes. In nearly 10 years, it has raveled over 1 billion miles. In an average orbit, it uses about the same amount of energy as twenty-four 100-watt light bulbs. Hubble is the first scientific mission of any kind that is specifically designed for routine servicing by spacewalking astronauts. It has a visionary, modular (dismantling capabilities) design which allows the astronauts to take it apart, remove the worn out equipment, and upgrade the instruments with new (and improved) ones.