Elements of space

Solar Eclipse 

   

A solar eclipse occurs when the shadow of moon falls on earth. It occurs only on new full moon day.

Types of solar eclipse

1.Total Solar eclipse:-

  It occurs when the moon completely covers the sun , as seen from earth . 

    

 2.  Partial solar eclipse

 It can be observed when only the partially shaded outer region of the shadow cast moon (Lunar penumbra) touches the earth.

3.Annular ecilpse

It occurs when the moon appears smaller than the sun as it passes centrally across the solar disk and a bright ring or annulus of sunlight remains visible during ecilpse.

    

4.Hybrid ecilpse

These are the rare form of solar ecilpse, which changes from an annular to a total solar eclipse along its path.

    

Lunar eclipse

A lunar eclipse occurs when the earth's shadow falls on moon . It occurs only on full moon day.

1.Total Lunar eclipse

 It occurs when the earth's shadow (Umbra) obscures all of the moon's visible surface.

    

2. Partial lunar eclipse 

It can be observed only when part of the moon's visible surface is obscured by the earth's shadow.

     

3. Penumbral lunar eclipse

It happens when the moon travels through the partially shaded outer region of the shadow cast by earth(earth's penumbra).

     

 The solar system

The sun and the celestial bodies which revolve around it form the solar system. It consists of large number of bodies such as planets,comets,asteroids and meteors . The gravitational attraction between the sun and these objects keeps them revolving around 

it.

  The earth revolves around the sun. It is a member of the solar system . It is a planet. There are seven other planets that revolve around the sun . The eight planets in there order of distance from sun are :-

Mercury,Venus,Earth,Mars,Jupiter,Saturn,Uranus and Neptune.

   

The Sun

The Sun is nearest star to us. It is continuously emmiting a huge amount of heat and light . The sun is the source almost of all energy source of earth. In fact , the sun is the main source of heat and light for all planets

The Planets

The Planets look like stars but they don't have their light of their own . They merely reflect the sunlight which falls on them.

     A planet has a define path in which it revolves around the sun it is called orbit. The time taken by a planet to complete one revolution is called 'Period of Revolution'.

      Some planets are known to have moons/satellites revolving around them . Any celestial body revolving around them is called it's satellite . 

Mercury

The planet Mercury is nearest to the sun . It is the smallest planet of the solar system. Because Mercury is very close to sun , it is difficult to observe it, as most of time it is hidden in the glare of sun. It can be observed just before sun rise or Just after the sunset. 

     So it is visible only at places where trees or building do not obstruct the view of horizon. Mercury has no satellite of it's own.

    

Venus 

Venus is earth's nearest planetary neighbour . It is the brightest planet in the night sky . Sometimes Venus appears in the eastern sky before the sunrise.

  Sometimes It also appears in the western sky. Venus has no satellite of it's own. Rotation of Venus is somewhat different . It rotates from east to west.

     

Earth

The earth is the only planet in the solar system on which life is known to exist.

       Some special environmental conditions are responsible for existence and continuation of life on earth. These include the right distance from the sun so that it has right temperature range, the presence of water,suitable atmosphere and a blanket of ozone. From space , the earth appears blue and green due to the reflection of water and landmass on it's surface . The earth has only one moon revolving around it . 

       

Mars

The first planet outside the orbit of earth is Mars. It appears slightly reddish and therefore it's a red planet. Mars has two natural satellites.

   

Jupiter

Jupiter is the largest planet of the solar system. It is so large that about 1300 earth's can be placed in this giant planet. However the mass of Jupiter is about 318 time more than the earth. It rotates rapidly on its axis. 

Jupiter has 71 natural satellites. 

      

Saturn

Beyond Jupiter is Saturn that appears yellowish in colour. There rings are special to see. These rings are not visible with naked eye. Saturn has 62 satellites of it's own . 

    

Uranus and Neptune

These are the outermost planets of the solar system . These can be only seen by large telescopes. Like Venus Uranus also rotates from east to west . The most remarkable feature of Uranus is it has highly tilted axis. As a result, in its orbital motion it appears on it's side.

    

Other Elements of Space

Asteroids

There is a large distance between Mars and Jupiter . This gap is occupied by a large number of small objects that revolve around the sun. These are called Asteroids.

    

     

Comets

Comets are also members of our solar system. They evolve around the sun in highly elliptical orbits. However , their period of revolution round the sun is very long. A comet generally appears as a bright head with a long tail . The length of tail grows in size as it approaches the sun. The tail of comet is always directed away from sun. 

     

Meteors and meteorites

These are commonly known as shooting stars , although they are not stars . They are called meteors . A meteor is usually a small object that occasionally enters the earth's atmosphere. It has a very high speed. The friction due to the atmosphere heats it up. It glows and evaporates quickly. That is why bright streak lasts for short time. Some meteors are very large as they can reach the earth before evaporating completely. The body that reaches earth is called meteorite.