(a) How does a planet differ from a star

Planet

• They are celestial bodies that do have light of their own but reflect the light from the sun
• They are spherical in shape
• There are eight planets in our solar system
• E.g. Earth

Star

• They are celestial bodies that have their own light and heat
• They are huge bodies made up of gases
• There are numerous starts in our galaxy.
• E.g. Sun

(b) What is meant by the ‘Solar System’?

The solar system means various objects that travel in orbit around it. It refers to the sun, the eight plants, dwarf-planet, satellites, asteroids, meteoroids and dust particles.

(c) Name all the planets according to their distance from the sun.

The planets according to the distance from the Sun:

1)Mercury

2)Venus

3)Earth

4)Mars

5)Jupiter

6)Saturn

7)Uranus

8)Neptune

(d) Why is the Earth called a unique planet?

• The Earth is called a unique planet because-
• Only it has conditions that are favourable to support life.
• It has suitable temperature for life. It is neither too cold nor hot.
• It has water and air, which are a must for survival.
• It has ozone layer that protects the life from harmful radiations.

(e) Why do we see only one side of the moon always?

We can see only one side of the moon always-

• It revolves around the Earth in about 27 days.
• It takes exactly the same time to spin on its axis.
• Therefore, the places on the moon always correspond to the places on the earth

(f) What is the Universe ?

The universe is an endless space that holds everything from the smallest particle to the biggest galaxy. It consists of innumerable galaxies, celestial bodies, clouds of dust particles, gases, etc.

Fill in the blanks-

(a) A group of ________ forming various patterns is called a ________.

(b) A huge system of stars is called________.

(c) ________is the closest celestial body to our earth.

(d) ________is the third nearest planet to the sun.

(e) Planets do not have their own________ and ___________________.