THE EARTH AND THE SOLAR SYSTEM

        

            THE EARTH AND THE SOLAR SYSTEM

Our Sun: Our sun is much closer to us than any other star. Light from the Sun takes about eight minutes to reach the Earth. Our Sun is now about halfway through its middle age. It is estimated that it will continue to give us light and heat for another 500 million years. It is an average size star.

The Sun is a huge ball of burning gases. It has a diameter of about 13,00,000 kilometres or nearly 100 times that of the Earth. By volume it is about 10,00,000 times larger than the Earth. It is estimated that the temperatures on the Sun's surface is about 6,000 degree Celsius. It has a gravitational pull which keeps the planets from moving too far away from its orbit. It is about 150 million kilometres from the Earth.

 

Why Sun is important in our lives?

Sun is important in our lives, because of the following :

1) It is the biggest source of heat and light on the Earth . Without these the Earth would have been too cold to sustain life.

2) The heat and light from the Sun is essential for plants to make their own food.

3) The Sun is important as it helps in changing seasons on Earth. 

4) The Sun causes water and   air currents which cause movements and weather.

What is universe?

The universe includes all celestial bodies, animals, plants, minerals, gases, everything we can see, feel and sense.

What is Nebula?

 

Nebula is a very mass of gas and dust. It created celestial bodies. All stars are formed by Nebula and thus it is also called the mother of all stars and celestial bodies.

What are stars?

Stars are a huge mass of burning gases. They emit light and heat. Stars are of varying in sizes and are very far apart.

What are Constellations?

Some stars have a similarity in position and movement . Therefore, they look like fixed patterns in the sky. Such patterns are called constellations. The Ursa Major, the Cassiopeia, the Orion's Belt, the Ursa Minor. etc. are some commonly known  Consellations.

What is Galaxy? 

Many constellations, the Sun and all the stars form one galaxy. The belt of stars is a galaxy is also called Akash Ganga. There are many such galaxies in the universe.

What are planets?

Planets are celestial bodies which are solid in nature and revolve around a star. They have a fixed path called the orbit. Plants are of many sizes. They do not have their own light or heat but reflect the light of the star they revolve around.

What is the Solar System?

The Sun along with its set of planets and other natural objects moving around it are jointly referred to as a system called the Solar System. This  is also commonly known as the Sun and its family. There are eight planets in the solar system. These are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Mercury: Mercury is the closest planet to the Sun.It does not have any satellite. It takes 88 days to complete one revolution around the Sun. It rotates on its axis in 59 days.

Venus: Venus is the second planet from the Sun. It is also known as the twin of the Earth. It is also known as the morning or evening star because it is easily visible in the sky in early morning and early evening. It has no satellite. Venus takes 255 days to complete a revolution around the Sun. It rotates on its axis in 243 days.

Earth: Earth is the third planet from the Sun. It takes 365 1/4 days to complete one revolution around the Sun. Due to large amount of water on it , it is also known as Blue Planet.It has one satellite or the Moon. The Earth rotates on its axis in one day. 

                                  The Earth is like a flattered ball, slightly bulging in the middle and slightly flat at the top and bottom. Such a shape is called a geoid.   It spins like a top and completes one rotation in nearly 24 hours.It also keeps revolving around the Sun in an anticlockwise direction.

Why Earth is a unique planet?

Earth is a unique planet, because -

1) Earth is the only planet in the Solar System where life exists.

2) It has water, land and air. 

3) It is favourable to sustain life as it is not too cold and not too hot.

4) Presence of various gases like oxygen, carbon dioxide and nitrogen in its atmosphere support life.

Mars: It is the fourth planet from the Sun. It is also called the red planet due to the large presence of red-oxides in its soil. It revolves around the Sun in 687 days. It has two satellites or moons revolving around it. It spins on its axis in one day. 

Jupiter : It is the fifth planet from the Sun and the largest planet of the Solar System. It takes 11 years and 11 months to revolve around the Sun.It finishes one complete rotation in 9 hours and 56 minutes or nearly 10 hours. It has 16 satellites or moons revolving around it. 

 Saturn: Saturn is the sixth planet from the Sun and is the second largest planet of the Solar system. It has rings around it and this makes it one of the distinct and beautiful planet of the solar system.The rings are made of dust, rocks and ice. It revolves around the Sun in 29 years and 5 months. It rotates at a high speed of 10 hours and 40 minutes on its own axis.It has over 30 satellites or moons.

Uranus : Uranus is the seventh planet from the Sun. It is the third largest planet of the Solar System.This also has a ring around it. It orbits around the Sun in 84 years. It rotates in 17 hours and 14 minutes on its axis. Uranus has 17 satellites or moons revolving around it.

Neptune: Neptune is the eighth and the furthest planet of the Solar System. It is the fourth largest planet. This also appears blue due to the presence of methane gas. It revolves around the Sun in 164 years. On its own axis, it rotates in 16 hours and 7 minutes. It has eight satellites or moons around it.

Some other Celestial Bodies: 

Moons: Moons are satellites of the planets. They revolve around the planet in their own orbit and continue to do so while the planet revolve around the Sun. Mercury and Venus have no moons around them. There ate other man made satellites which sent to orbit around the Earth. Such satellites are called artificial satellites.

Earth's Moon: The Moon is the only natural satellite of the Earth. It is about 3,84,000 kilometres from the Earth. The Moon rotates around the Earth in 27 days and  8 hours and it also takes the same time to spin on its axis.It has no light of its own but appears to shine because it reflects the light of the Sun falling on it. 

ASTEROIDS: Asteroids are small rocky celestial bodies moving around the Sun between the orbits of Mars and Jupiter.

METEOROIDS : Meteoroids are small rocky pieces which float freely around the Sun in outer space.

COMETS: Comets are a type of asteroid. They are visible from Earth on rare occasions.Halley's Comet is one example of comet which was seen in 1986 and will be visible after 76 years. In India, it is known as Pucchal Tara . It would be visible again in 2062.

* Aryabhata was the first satellite launched by India.

*ISRO - Indian Space Research Organisation.

* Neil Armstrong was the first astronaut to put his foot on the surface of the Moon in July 1969.