Space

By Aarav5M

Contents

• 1. The Sun (page 1) 8.Uranus ( page 8)• 2. Mercury (page 2) 9. Neptune and Pluto• 3. Venus ( page 3 ) (page 9)• 4. Earth ( page 4 ) Glossary ( page 10)• 5. Mars ( page 5 )• 6. Jupiter (page 6)• 7. Saturn ( page 7)

The Sun

• The Sun, as we see it, is a huge ball of very hot gas measuring about 1,380,000 kilometers in diameter. Dark spots can often be seen on the Sun’s surface, these are known as sun spots and they come and go frequently. These spots stand out as patches since they are cooler as compared to the hot area by which they are surrounded. Huge flames called prominences are constantly shot of the surface of the Sun.

Mercury

• Almost twice the size of Pluto and 4879 kilometers in the diameter, Mercury is the closest planet to the Sun at a distance of only 57.9 million kilometers. It only takes 58.65 days to revolve once on its axis which means that it has a day which is equal to 180 Earth days. Like Venus, Mercury does not have any moons: Mercury has the highest orbital velocity because of which it takes 88 days to complete on revolution around the Sun.

Venus

• Next to Mercury, Venus is the hottest and the brightest planet in the Sun family. Venus has a diameter of 12,104 kilometers and is located 108 million kilometers from the Sun. Venus rotates on its axis in a clockwise direction in 243.16 days thus having a four year day. It travels at a speed of 35 kilometers per second and takes about 225 days to orbit the Sun once.

Earth

• Our planet , the Earth, is a part of the Sun’s family and is located about 150 million kilometers away from it. The Earth took close 100 million years to become a glowing ball comprising of molten rock. Volcanoes on the surface regularly threw out this molten rock and other gases.

Mars

Mars, the fourth planet in the Sun’s family and has a diameter of 6,794 kilometers and its orbits at a distance of 228 million kilometers from the Sun. The surface gravity on Mars is 0.38 of the Earth’s gravity. Mars moves at a 24 kilometres per second and takes about 780 days to complete one revolution around the Sun. One rotation on its own axis is completed in about 24 hours and 37 minutes. It has two moons called Phobos, which is 23 kilometres in diameter and Demos which is 13 kilometres in diameter.

Jupiter

Jupiter is largely made out of liquids, gases and swirling clouds of hydrogen and helium. These liquids and gases become denser and denser as we move towards the planet’s center. Jupiter is the largest planet in the Solar System with a diameter of 1,42,884 kilometres. Besides this it is also the fastest spinning planet, it takes only 9 hours and 50 minutes to complete one rotation. It is a cold planet with temperatures as low as -150o centigrade.

Saturn

• Saturn is the sixth planet, in order of the revolution, in the family of the Sun. It has a diameter 1,20,536 kilometres and is located in orbit about 1427 million kilometres away from the Sun. Saturn is 95 times larger and has a surface gravity 1.16 as compared to Earth.

Uranus

Uranus was discovered by William Herschel in the year 1781. Herschel built the largest telescope of that age to do so. Located at about 2890 kilometres from the Sun, Uranus is the seventh planet in our Solar System. Third largest in size, Uranus has a diameter of 51,118 kilometres and it is about 15 times the size of Earth but has a surface gravity of only 0.93 as compared to Earth. Uranus takes 17 hours to spin on its axis and about 84 years to complete one revolution around the Sun.

Neptune and Pluto

Neptune is the eighth planet and farthest planet from the Sun in the Solar System. Till around 1929, the outermost planet known to man was Neptune. In 1915, the American astronomer; Percival Lowell discovered that the movement of Uranus and Neptune was affected by something which existed beyond Neptune. This opinion led to the search of the new planet and it was in February 1930 that an astronomer named Tombaugh discovered Pluto, the ninth planet. Pluto has a diameter of about 2445 kilometres which is about one- fifth of the Earth’s and it takes 6 days and 9 hours to complete one rotation around the axis.

Atmosphere• The Earth is surrounded by a thick blanket of air, called the

atmosphere, which is made up of about 20 gases. The two main gases are oxygen and nitrogen. It also contains water vapor and dust particles.

• Air is matter and, like all matter, it has weight. Weight is the measure of the pull of gravity on matter. If you place a stone on a pair of scales and it weighs 5 kilograms, it means that gravity is pulling the stone with a force of 5 kilograms.

• Earth's gravity pulls on each particle of gas and dust in the atmosphere. If it was possible to place this on a pair of scales it would weigh about 5,700,000,000,000,000 (quadrillion) tons !

Water Vapor

• Water vapor exists as an invisible gas in air. The amount of water vapor in air varies according to the temperature and density of air. The amount of water vapor ranges from a trace amount up to 4% of the mass of air. Hot air can hold more water vapor than cold air, so the amount of water vapor is highest in hot, tropical areas and lowest in cold, polar regions.

How many moons does each planet have???

• All planets have at least one moon, except for Mercury and Venus, which have none. Earth has only one moon, Mars has two, Jupiter has 63 known moons, Saturn has 61, Uranus is orbited by 27 moons and Neptune has a total of 13 moons. Although Pluto is no longer considered a planet, we do know Pluto is orbited by 3 moons too.

Solar Eclipse

• A solar eclipse in when the Moon passes in front of the Sun casting a shadow on the Earth (this is also known as an occultation). As the Sun’s distance from Earth is around 400 times the Moon’s distance and the Sun’s diameter is around 400 times the Moon’s diameter, the Sun and the Moon as seen from Earth appear to be approximately the same size. There are several sorts of eclipses; partial, annular and total.

Glossary

• frequently: often many time; at short intervals• Prominences: an eruption of a flamelike

tongue of relatively cool, high- density gas from the solar chromosphere into the corona where it can be seen during a solar eclipse or by observing strong spectral lines in its emission spectrum.

• Orbital velocity: the minimum velocity at which a body must move to maintain a given orbit.

Glossary (page 2)• Surface gravity: something that pulls you to the

ground.• Contraction: The change in a muscle by which it

becomes thickened and shortened.• Comprising: Ex: My classroom was comprising 6

Indians, 7 British, 1 Australian, 2 Indonesian, 2 Japanese, 1 Vietnamese, 1 Dutch, 1 German,1 Belgian.

• Hydrogen and helium: 2 different type of gases

Glossary( page 3)

• Diameter: a straight line passing through the center of a circle or a sphere and meeting the circumference or surface at each end.

• Revolution: A procedure or course, as in a circuit, it goes back to the starting point.

• Astronomer: an expert in astronomy; a scientist observer of celestial bodies.

• Axis: The line about which a rotating body , such as the earth, turns.

Glossary page 4• Density: The relative heaviness of objects, measured in units

of mass or weight per units of volume.

• water vapor: A dispersion, in air, of molecules of water, especially as produced by evaporation at ambient temperatures rather than by boiling.

• oxygen and nitrogen: Two main type of gases in the atmosphere

• Occultation: the passage of one celestial body in front of another, thus hiding the other from view: applied especially to the moon's coming between an observer and a star or planet.

• annular: shaped and formed of a ring

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