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Hockey’s Jadoogar – Dhyan Chand

Dhyan Chand popularly known as hockey's jadoogar. Dhyan Chand was born on 29th August, 1905 at Allahabad. His father was in the British Indian...
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Astronomy and Solar System

Our Solar System

The Sun, the nine known planets, their 31 known satellites, a great number of asteroids, and some other bodies like comets and meteors constitute the solar system.


The incandescent, approximately spherical heavenly body around which the planets rotate, is known as the Sun. It is one of some 1.00,00,00,00,000 stars which constitute our galaxy, its mean distance from the earth is approximately 9,29,00,000 miles, diameter about 864,000 miles, mass 2×10^27 tons and its average density 1.4 grams per cc.

Sun’s Temperature

The outer surface of the Sun, called photosphere, has a temperature of about 6000 C and its interior temperature is about 13,000,000 C. Such a high temperature inside the sun give rise to thermonuclear reactions in which Hydrogen is converted into Helium.The heat produced in this reactions makes up the loss of heat by Sun`s radiation, thereby keeping the sun’s temperature constant and high.


These are the region on the Sun`s photosphere visible are irregular dark patches scattered on either side of sun’s equator, emitting strong magnetic field which disturbs wireless communication and produces magnetic storms on the earth.

Production of holes

A luminous ring sometimes observed around the sun or Moon called halo is caused by the reflection of light by ice crystals present in the atmosphere.


The bodies revolving around the sun are called planets.These are not self-luminous but shines by radiating the light received from the sun.The orbits of all planets are elliptical.Their sizes, speeds, and distances from the sun vary.

Names of planets

There are nine planets so far known. In order of their nearness to the sun, they are (i) Mercury, (ii)Venus (iii)Earth (iv)Mars (v)Jupiter (vi)Saturn (vii)Uranus (viii) Neptune (ix)Pluto.

Farthest and Nearest planets

Pluto is the planet farthest from the sun while mercury is the planet nearest to the sun.

Largest and smallest planets

Jupiter with its diameter of about 85,750 miles (about eleven times of earth’s diameter) is the largest known planet of the solar system. Mercury with a diameter of about 3,030 miles is the smallest known planet.

Brightest planet

Venus appearing as a brilliant crescent is the brightest known planet.

Heaviest planet

Jupiter is the heaviest planet (314.5 times heavier than the earth).

Planets with the largest number of satellites

Jupiter has the maximum number of satellites (69).
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