COMPOSITION OF THE SOLAR SYSTEM

The Sun

It’s the centre of the universe.

Characteristics of Sun

• It’s a star.

A star is a heavenly possessing its own light which it transmits. Nebula/galaxy is a cluster of stars.

The earth is in a galaxy called The Milky Way.

1. It’s made of very hot gases mainly hydrogen (70%) and helium (30%).
2. Has a diameter of 1392000km.
3. Surrounded by a layer of gas which has boiled from its surface which is called corona.
4. Rotates on its own axis in anticlockwise direction.
5. Has gravitational pull which holds all the planets in orbit around it.

An orbit is a path which a planet or a satellite follows around a star or a planet.

1. Temperature at its centre is 15m◦c and at the surface is 5500◦c.
2. Radiates solar energy which is very important for all forms of life on the earth.

 

The Planets

Planets are large spherical celestial/heavenly bodies in space.There are 9 planets in our solar system.

Characteristics of the Planets

1. Spherical in shape
2. Don’t have their own light but reflect it from the sun.
3. Revolve around the sun in anticlockwise direction.
4. Have their own force of gravity
5. Only one is known to support life.

 

The following are the planets arranged in order from the one nearest to the sun.

Mercury

1. Nearest from the sun
2. Its 58m km from the sun
3. Has no satellites
4. Takes approximately 88 earth days to revolve around the sun

Venus

1. 2nd planet from the sun
2. It’s 108m km from the sun
3. One of the brightest planets
4. Can be seen clearly with naked eyes
5. Takes approximately 225 earth days to revolve around the sun
6. Slightly smaller than the earth
7. Has no satellites
8. Together with the earth they are called twin planets due to having many similarities

 

Earth

1. The 3rd planet from the sun
2. The earth and the heavenly bodies make the universe
3. The only planet that supports life
4. The home of man
5. Approximately 149m km from the sun
6. Takes 365 ¼ days to revolve around the sun
7. Has one satellite, the moon

Mars

1. Also called The Red Planet because when it’s observed through a telescope it appears reddish.
2. The 4th from the sun
3. Slightly smaller than the earth
4. Approximately 228m km from the sun
5. Takes 687 earth days to revolve around the sun
6. Between Mass and Jupiter there are small celestial bodies called planetoids.
7. Has no satellite.

Jupiter

1. 5th planet from the sun
2. Approximately 778m km from the sun
3. Largest in the universe
4. Rotates on its own axis at very fast speed
5. Has flattened poles due to its fast speed of rotation
6. Has very thick layers of ice on its surface
7. takes 12 earth years to revolve around the sun
8. Has 16 satellites

Saturn

1. 6th planet from the sun
2. Second largest planet
3. Approximately 1427m km from the sun
4. Takes 29 ½ earth years to revolve around the sun
5. Has a ring around it
6. Has 18 satellites

Uranus

1. 7th planet from the sun
2. About 4 times bigger than the earth
3. Approximately 2870m km from the sun
4. Also rotates very fast
5. Also has flattened poles due to fast speed of rotation
6. It appears greenish foe being surrounded by methane gas
7. Has 8 satellites
8. Takes 84 earth years to revolve around the sun

Neptune

1. One of the farthest from the sun
2. 8th planet from the sun
3. Approximately 4497m km from the sun
4. Has 8 satellites
5. Takes 165 earth years to revolve around the sun
6. Very similar in size, colour and character with Uranus

Pluto

1. 9th planet from the earth
2. Farthest from the sun
3. The smallest
4. 1/6 the size of the earth
5. Approximately 5900m km from the sun
6. Takes 248 earth years to revolve around the sun
7. Has one satellite
8. Very little is known about it Other Celestial Bodies