Page 88 - ACTIVE SCIENCE 4 TOC

Artificial Satellites

Artificial satellites are those objects which are made by man and sent into
space to orbit a planet. They are launched using powerful space rockets and keep

revolving around a planet. The first man-made satellite was Sputnik 1, launched
by Russia in the year 1957. Since then thousands of satellites have been made by

different countries. India made its first satellite in the year 1975 and named it
Aryabhatta.

Let’s Recapitulate

Fill in the blanks.
1. ______________ is the largest object in the solar system.

2. ______________ is also called the blue planet.
3. ______________ is the second largest planet after Jupiter.

4. The farthest planet from the sun is ______________.

S tars

Stars are small twinkling objects in the sky which

can be seen only at night. They are huge balls of hot
gases which produce their own heat and light. They
are of different colours and sizes. There are millions

of stars in our galaxy, Milky Way, and some of them
are larger than the sun. We cannot see the stars
during daytime because the sun is much brighter

as compared to them. They are far from the earth
so they look like tiny spots. The sun is the nearest Milky way

star to the earth and therefore appears so big and North
bright. Pole
Equator Axis of
23.5 0 Rotation
Motion Of The Earth
Northern
The earth not only revolves around the sun on its orbit Hemisphere
but also rotates on its own axis. The axis is an imaginary

the line passing through the North Pole, South Pole and Southern
centre of the earth. The earth is tilted at an angle of Hemisphere
23.5 degrees on its axis and rotates from west to east.

Another imaginary line that divides the earth into South
Pole

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