class 6 sst geog 2016

EARTH AND THE SOLAR SYSTEM

B1. A group of stars which forms a definite pattern is called a constellation.

2. Millions of stars together form a group called a galaxy. Our sun belongs to the galaxy :- Milky way .
3. The moon takes 27 days and 8 hours to go round the earth once.
4. An object designed by man to revolve round the earth or any other heavenly body is called an artificial satellite . Eg. INSAT 1.
5. The small celestial bodies that revovle around the sun , which are between the orbits of Mars and Jupiter are called asteroids or minor planets.

C1. The two stars at the head of the Big Dipper of the constellation Great Bear always point towards the pole star.They help navigators to find out the north direction.

2.A faint band of light in the sky is called the Milky Way . It is a band of stars in our galaxy. The sun is a part of this galaxy.

3.Planet Venus is the brightest planet. Mars looks red and Saturn has rings around it.

4. When meteorids enter the earth's atmosphere they start burning and cause a flash of light as they fall. We call them shooting stars or meteors.

D1. The Solar system consists of the sun, the eight planets , the moons, and other celestial bodies that move around the sun.Besides there are dwarf planets ,asteroids, meteoroids also move round the sun.

2. The planets have two types of motions_ rotation and revolution.
   Rotation:- Each planet spins or rotates on its axis. A day on a planet is the time taken by it to complete one rotation.eg. The earth takes 23 hours 56 minutes to complete one rotation.
   Revolution:- All the planets move round the sun on its orbit.
   3. The earth is the only planet which has life on it. The factors that support it are:-Moderate temperature, Water in liquid form and favourable atmosphere.

E2. Neptune is the coldest planet because it is the farthest planet from the sun.