Maharashtra Board Class 5 EVS Part I Chapter 1 Our Earth and Our Solar System PDF Download

Our Earth And Our Solar System

When we look up from an open ground, we see the sky. In a clear night sky we can see many stars. They are very far away from the earth.

Some stars are prominent while some are tiny and faint. If we look at them carefully, we find that many of them twinkle, but some do not.

The sun and the moon are comparatively close to the earth. So, we can see their round shapes clearly. The sun, the moon, the stars, the planets, etc. are all known as heavenly bodies.

Try This

Observe the sky on two clear nights, keeping a gap of about a week between them. Base your observation on the following points:

The brightness of the heavenly bodies

Whether they twinkle

Their colour and size

Changes in their positions

On both nights, draw a picture of the illuminated portion of the moon and note how it changes from day to day.

For teachers: For the sky-watching activity, call the children along with their guardians to a large open area on a clear dark night.

Stars

The heavenly bodies that twinkle are called stars. Stars have their own light.

The sun is a star. It is closer to us than any of the other stars. Hence, it appears big and brilliant. In its bright light, during the day, we cannot see other stars.

Planets

The heavenly bodies that do not twinkle are called planets. Planets do not have light of their own. They get light from the stars. Planets revolve around a star, even as they rotate around themselves.

The Solar System

Our earth is a planet. It gets its light from the sun. It moves around the sun. Its movement around the sun is called the revolution of the earth.

Besides earth, there are seven other planets that revolve around the sun. They are Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune.

Teacher's Note

You can see the moon at night because it reflects the sun's light. Just like how we see things in a mirror, the moon shows us the sun's light.

Exam Trick

Remember: Stars twinkle, planets do not. Think of it like this - twinkling lights blink on and off, just like stars.

Points to Remember

Stars have their own light and they twinkle.
Planets do not have their own light. They get light from stars.
The earth is a planet that revolves around the sun.
There are eight planets in our solar system.
The sun is the centre of the solar system.

Every planet in the solar system revolves around the sun along a specific path. This path is known as that planet's orbit. The sun, which is a star, and the planets that revolve around it are together called the solar system. Besides the planets, the solar system also includes various other heavenly bodies.

Other Heavenly Bodies In The Solar System

Satellites

Some heavenly bodies revolve around planets. These are called satellites. Satellites too get their light from the sun. We see the moon at night. It revolves around the earth. Hence, it is called a satellite of the earth.

Most of the planets in the solar system have satellites. The planets revolve around the sun along with their satellites.

Dwarf Planets

There are some smaller heavenly bodies that revolve around the sun. They are called dwarf planets. Of these, the most well-known is Pluto. Dwarf planets revolve independently around the sun. They have an orbit of their own.

Asteroids

Between the planets Mars and Jupiter, there is a band of numerous small heavenly bodies. They are called asteroids. Asteroids also revolve around the sun.

Compared to the sun, other heavenly bodies in the solar system are much smaller. The moon is closest to the earth. That is why, it appears to be so big although it is actually very much smaller than the sun.

A diagram of the solar system is given below. In it, you see the sun in the centre, the heavenly bodies that revolve around it and their orbits. The planets, satellites, dwarf planets and asteroids are all part of the solar system.

Teacher's Note

The moon is our earth's only satellite. Like how a son revolves around his father, the moon revolves around the earth.

Exam Trick

Remember: Satellites = revolve around planets. Planets = revolve around stars. Think of it like a chain - star, planet, satellite.

Points to Remember

Satellites are heavenly bodies that revolve around planets.
The moon is the earth's only satellite.
Dwarf planets are smaller heavenly bodies that revolve around the sun.
Asteroids are small rocks between Mars and Jupiter.
All these bodies together make up our solar system.

India's Space Missions

A New Word - Space

The emptiness between and beyond the stars and planets is called space or outer space.

Chandrayaan

On 22 October 2008, the Indian Space Research Organization, ISRO, launched a spacecraft to the moon. The mission is known as Chandrayaan-1.

Mangalyaan

Mangalyaan is another important Indian space mission. It is known as M.O.M. or Mars Orbit Mission. It was launched on 5 November 2013. It got established in an orbit around the planet Mars on 24 September 2014. ISRO achieved this feat in its first attempt. Both these missions are unmanned, i.e. there were no people on board these spacecraft. The objective of the missions is a deeper study of the moon and Mars.

Can You Tell?

Look at the picture of the solar system and answer the following questions.

(1) Which planet is nearest to the sun?

(2) At what position is the earth from the sun?

(3) Which planet is placed between the earth and Mercury?

(4) Name the planets beyond the orbit of Mars in serial order.

(5) Which planet in the solar system is furthest from the sun?

Gravity

All heavenly bodies exert a force of attraction or a pull on one another. This force is called the force of gravity.

The sun exerts a gravitational pull on all planets whereas the tendency of the planets is to move away from the sun. As a result of these two forces, a planet keeps revolving around the sun at a fixed distance in a fixed orbit. In the same way, satellites revolve around their planets.

In Which Direction Do These Things Fall?

(1) Leaves, flowers, fruits from a tree.

(2) Rocks that come loose from a hillside.

(3) Rain falling from the sky.

Due to the earth's gravity, all things on the earth remain on it. Even if we throw something upwards with great force, it finally falls down to the ground.

Teacher's Note

Gravity is the force that pulls things down to earth. When you throw a ball up, gravity brings it back down, just like how ISRO uses rockets to fight against gravity.

Exam Trick

Remember: Gravity = pull down. All things fall down because of gravity. Think of gravity like an invisible string pulling everything to the earth.

Points to Remember

Gravity is a force that pulls things towards the earth.
All things fall down because of gravity.
The sun's gravity pulls planets around it.
Planets' gravity pulls satellites around them.
Even light things fall down because of gravity.

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