the solar system.pdf

7/29/2019 The Solar System.pdf

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HARI OM MAURYA HARI OM MAURYA HARI OM MAURYA

The Solar System

The Sun and bodies revolving around it, which includes 8 planets, satellites, comets, meteors andasteroids, together constitute the solar system. The source of energy for the sun is the nuclear

fusion reaction in which Hydrogen changes into Helium.

The Sun

The part of the sun that we can see in known as photosphere. The outer most part of the sun,

which is visible only at the time of a solar eclipse, is known as corona. A storm of hot atoms

which dissipates from the photosphere of the Sun, overcomes its gravity and goes into the outer

space, is known as Solar Flares. When Solar Flares reach the Earth's atmosphere, after colliding

with the air and dust particles, it produces a spectacular colourful effect. In the North-Pole

region, this effect can be seen as Aurora Borealis and in the South-Pole region as AuroraAustralis. The regions from where the solar flares originate, some dark spots are seen, these arecalled Sun Sport. ISRO (Indian Space Reserch Organisation) is planning to launch a satellite

called Aditya to study the sun. Time taken by the light to reach the earth form sun is 8 min 18

sec.

The Planets

These are the celestial bodies, originating from the sun and are revolving around it. They do nothave their own light and receive light and heat from the Sun. All the planets revolve round the

sun from west of east. But, Venus and Uranus are the exceptions, which revolve around the sun

from east to west. 'Terrestrial Planet' are Mercury, Venus, Earth and Mars because of theirstructure being similar to that of the Earth. 'Jovian Planets' are Jupiter, Saturn, Uranus

and Neptune bacause their structures are similar to the Jupiter.

Mercury : This is nearest to the Sun and it is the smallest planet of the solar-system. Ittakes 8 8 days to complete one revolution of the sun. Life is not possible on this planet

because of the absence of atmosphere. This member of the solar family has no natural

satellite. Mariner-10 was the only artificial satellite.

Venus : It is the Second closest planet to the Sun. This planet, unlike other planets, goesaround the Sun from east to west and is the nearest planet to the Earth, it is the brightest

object seen in the sky, after the Sun and the Moon therefore it is called 'Morning star' is

well as 'Evening star'. Being almost similar to the Earth in size and mass it is also calledthe sister planet of the Earth. Its atmosphare is mainly composed of C02 (90-95%), which

produces a 'Pressure cooker condition' on this planet. Venus also has no natural satellite.

Earth : it rotates on its axis from west to east. It is tilted on its axis by 23%. It takesabout 365% days to complete one revolution around the sun. Its average distance from

the sun is about 150 million km. It looks blue when seen from the outer space due to the

presence of large amount of water, hence it is also called the 'Blue Planet'.

Mars : It is called 'Red Planet' bacuse of its red appearance. It is the only planet, besidesearth, where the possibility of life exists, because of the presence of atmosphere andglacial water as observed by the artificial satellite, 'Mars Odyssey'. Its rotation is like that

the earth. It has two natural staellites-Phobos and Domos, the smallest satellites of the


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solar system. The highest point on this planet is Nicks Olympia which is three times as

high as Mt. Everest.

Jupiter : This is the largest planet of the solar system. It has 28 natural satellites goingaround it wherein Ganymede is the largest satellite of the planet as well as of the solarsystem. Ayo, Europa, Calisto, Almethia, etc are other satellites. The atmosphere of the

planet is composed of Hydrogen, Helium, Methane and Ammonia. It possesses the

quahties of both a planet and a star, as it has its own radio energy. Its most distinguish

feature is the great red spot, which is believed to be a complex storm in the atmosphere of

the planet.

Saturn : Its most spectacular and mysterious characteristic is the presence of fullydeveloped rings around it. These rings are composed of Small particles, which go around

this planet collectively, due to its gravitational force. It is also called the 'Gaseous Globe'Galaxy like Planet. It appears yellow in the sky. Like Jupiter, the atmosphere os Saturn is

also composed of Hydrogen, Helium, Methane. 30 Natural satellites of this planet have

been discovered, till date, of which Titan is the largest, having the size.comparale toMercury and its Own atmosphere and the gravitational force. Other satellites of Saturn

inclued Mimansa, Ensiladu, Tethys, Phobe etc. Saturn is the last planet of the solarsystem that can be seen through the naked eyes.

Uranus : Due to higher inclination of axis, it is also known as 'Lying Planet'. Uranusreloves the sun from east to west. Its atmosphere is composed of Hydrogen, Helium and

Methane. When seen through the telescope, it appears green. Being very far from theSun, it is very cold. It has 5 rings around it like Saturn (having 7 rings). These Delta and

Epsilon. This planet has 21 natural satellites. The Sun rises in its west and sets in its east.

Neptune : It was discovered by a German astronomer, Johan Galle. Its atmosphere isvery dense, consisting of Hydrogen, Helium and Methane. It appears light yellow in

colour. It has 8 natural satellites, of which Tritan and Mereed are important. Pluto: It was discovered in 1930 by Clyde Tombagh and was considered as the ninth and

the smallest planet of our solar system. But at the summit of International Astronomical

Union (IAU) held in Prague (Czech Republic) on 24 August 2006, scientists withdrewthe status of planet form it.

Satellites

These are the celestial bodies which revolve their respective planets and around the sun as well.

Like planets, satellites also do not have their own light and shine with the light of sun. Likeplanets, their orbits are alsoelliptical.

Asteroids

These are found between the orbits of Mars and Jupiter. These are celestial bodies with sizes

ranging from a few meters to hundreds of the kilometres of diameter, revolving around the sun.They have originated by the disintegration of the planets.

Planets according to their decreasing size:

1. Jupiter 2. Saturn 3. Uranus 4. Neptune 5. Earth 6. Venus 7. Mars 8. Mercury


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Planets according to their decreasing mass:

1. Jupiter 2. Saturn 3. Neptune 4. Uranus 5. Earth 6. Venus 7. Mars 8. Mercury

Planets according to their decreasing density:

1. Earth 2. Mercury 3. Venus 4. Mars 5. Neptune 6. Jupiter 7. Uranus 8. Saturn

Terrestrial Planets:

1. Mercury 2. Venus 3. Earth 4. Mars

Jovian Planets:

1. Jupiter 2. Saturn 3. Uranus 4. Neptune

Planets according to decreasing revolution period:

1. Mercury 2. Venus 3. Earth 4. Mars 5. Jupiter 6. Saturn 7. Uranus 8. Neptune

Meteors and Meteorites

Meteors are the celestial bodies composed of dust and gases. After coming under the influence of

earth's gravity, they move with a great velocity towards the earth. But, due to collision with theparticles of the atmosphere they burn and get converted into ash. Meteors which are large in sizeand do not burn completely and reach the surface of the earth are called meteorites.

Coments

There are the bodies composed of dust, ice and gases, which come from the colder and darker

areas, awayfrom the sun. They go around the sun in large and irregular orbits. While moving intheir orbits, when they come very close to the sun, they start glowing with a bright gaseous tail

always pointing away from the sun. Many a times, comets are visible to the naked eye and

present a very spectacular sight. Comet Halley, discovered by Edmund Halley, returns after

every 76 years.

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