Universe ,Solar System and Earth Rotation

8/13/2019 Universe ,Solar System and Earth Rotation

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6 The Earth is 23½o tilted on its axis and thus makes 66½o angle. It takes 23 hours 56 minutes and 4.091seconds to rotate on its axis. It takes 365 days, 5 hours and 48 minutes to revolve around the Sun. Mars isknown as Red Planet due to presence of Iron minerals. Phobos and Demos are natural satellite ofit.Jupiter is the largest planet and also known as “ Winter Planet” due to low temp .Ganymede is its oneof satellites ,it is also the haviest satellite of solar system.

7-Saturn satellite Titan shows antigreen house gas effect.Uranus is also known as Green Planet due topresence of Methane.William Heshel discovered it in 1781.T his is the first planet discovered by the

help of Telescope.Uranus and Venus rotate from east to west which is just oppoiste to all othersplanets. The axis of Uranus has large inclination so that is appears to be lying down, hence it bears thename “A Planet on its Side”.Neptune is very similar to Uranus and considerd its Twin.

8-Asteroids are known as minor planet. They are objects that revolve around the sun.They are mostlyfound between the orbits of Mars and Jupiter. Certain asteroids may have satellites. Trojan asteroids

are found in two clouds moving in the orbit of Jupiter, one moving ahead of it and the other moving behind

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it.

9-Miteors and Miteorits: Meteors and Meteorites are also called shooting stars.Meteors are fragments of

rocks, coming towards the earth, formed due to the collision of asteroids with one another.Meteors areusually small and due to heat produced by air resistance, burn up before they reach the Earth’ssurface.When meteors are large and do not burn up completely, they land on the Earth’s surface and areknown as Meteorites.

10-Comets: Comets move around the Sun in regular orbits, but their orbits are elongated ellipses that it

takes them hundreds and sometimes even thousands of years to complete one revolution around theSun.they are made of frozen gases.it is visible when it passed to sunIts ice melts and the gas and dust isswept back into a tail.The tail always points away from the Sun. So if it is travelling away from the Sun, ittravels tail first.

11-Constellation: To enable astronomers to roughly identify the position of the stars, the sky has beendivided into units. The units are known as Constellations.These constellations were named in honor ofmythological characters.At present 88 constellations are recognized.

MOTION OF EARTH AND THEIR IMPACT:

Rotaion of Earth:it rotated from west to east.thats why sun rising in east and sets in west. Therotation speed varies at different places on Earth, at any point upon the equator is at the rate ofapproximately 1,038 miles per hour, decreasing to zero at the poles.

Tilted axis and its impact: The Earth’s axis is not vertical. It makes an angle of 23 0 30’ with the verticalor 66 0 30’ with the plane of the Earth’s orbit. Rotation of the Earth on its tilted axis causes days and nightsto be of different lengths in different parts of the Earth. Since the Earth’s axis is tilted in the samedirection, the orientation of the Earth’s axis to the Sun’s rays is constantly changing as the Earth movesaround the Sun. Solstice is one of the two dates in the year on which the sun reaches greatest altitudenorth or south of the equator and is directly overhead along one of the lines of the tropics. Equinoxes are

the two days in a year when day and night are equal throughout the world are equinoxes. The two datesare March 21 and September 23

Coriolisis Force: The Coriolis force is defined as the evident deflection of objects moving in a straight

path relative to the earth's surface.The main cause is earth rotation. As a result of this Coriolis force thewinds moving in the Northern hemisphere are deflected rightwards, while those in the Southernhemisphere are deflected leftward. As latitude increases and the speed of the earth's rotationdecreases, Coriolis effect increases.

Revolution of earth: Earth revolves around the Sun in a counter-clockwise direction .It takes 365 days

6 hours, 9 minutes and 9.5 seconds to complete one revolution around the Sun.The path taken by Earth

for this revolution is known as the Earth's orbit . It is elliptical.Perihelion is the position of the earth or anyother planet in its orbit when it is at its nearest point to the sun. Aphelion is the position of the earth orany other planet in its orbit when it is at its greatest distance from the sun

Eclipses: An eclipse is an astronomical event which occurs when an astronomical object is temporarily

hidden, either by passing into the shadow of another body or by having another body pass between it andthe viewer. An Eclipse occurs when the sun, moon and earth are in a straight line.In solar eclipse the

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Moon's shadow crosses the Earth's surface. A solar eclipse occurs when the moon passes directly infront of the sun so that its shadow lies on the earth. In other words, the moon lies between the sun and theearth. A solar eclipse takes place on new moon day. The lunar eclipse takes place when the earth comesin between the sun and the moon and the shadow of Earth falls on moon. A lunar eclipse takes place on afull moon

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Universe ,Solar System and Earth Rotation