2. THE SOLAR SYSTEM
The solar system consists of the sun ,the eight planets and their
satellites and thousands of other small heavenly objects such
as comets, asteroids and meteors.
3. THE EIGHT PLANETS
The eight planets in their order of distance from the sun are :
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus and
Neptune
4. THE SUN
The sun is the nearest star from us.
The sun is 150×1000000 kilometres from the earth.
The sun is 109 times bigger than the earth.
The diameter of the sun is 14×100000 kilometres.
The temperature of the surface of the sun is 6000 degree C while
the temperature at the centre is 15 million degree celsius.
It is believed that the sun was formed about 5 billion years ago.
5. MERCURY
The planet mercury is the nearest to the sun.
It circles the sun at the shortest time .It takes only 88
days to complete one revolution.
The side facing the sun receives more light and heat, so
it is very hot .The other side away from the sun is quite
cold.
It has no natural satellite .
It is the smallest planet .
6. VENUS
Venus is the brightest planet in the night sky .
It has no natural satellite .
Unlike Earth ,it rotates from east to west .
It also shows phases like the moom .
It is visible 1-3 hours before sunrise and 1-3 hours after sunsrt .
7. EARTH
The Earth is the only planet in the solar system on which life is known to exist .
It has some special environmental conditions like the right temperature range, the presence of water, a suitable
atmosphere and a blanket of ozone responsible for the existence and continuation of life on Earth .
From space, the Earth appears blue-green due to the reflection of light and landmass on the surface .
The Earth has only one natural satellite –the moon .
The axis of the Earth is not perpendicular and is of 23½ degrees which is responsiple for the change of seasons
.
8. MARS
Mars is a reddish planet .Its red colour comes from the rust
in its soil .That is why mars is called the red planet .
It has two tiny natural satellites .
It is nearly half size of the Earth .
It possesses an atmosphere of carbon-di-oxide .
9. JUPITER
Jupiter is the largest planet of the
Solar system .
The mass of Jupiter is 318 times of our
Earth .
It has 63 known satellites .The Ganymede is one of the
biggest satellite and is also bigger than mercury .
10. SATURN
Saturn has the most visible and beautiful rings that encircle the
planet, made of ice and rock particles .
It appears yellowish in colour .
It has 60 confirmed satellites .
It is the least dense among all the planets .Its density is less than that
of water .
11. URANUS
Uranus also has a ring system .
It has 27 natural satellites .
Like Venus ,Uranus also rotates from east to west.
The most remarkable feature of Uranus is that it has
a highly tilted rotational axis which is inclined at 97
degrees .The Earth spins like a ball while Uranus rolls
like a ball .
12. NEPTUNE
Neptune also has a ring system .
We need a telescope to see it at the night sky .
It has 13 known satellites .
