2nd Class EVS Our Universe

OUR UNIVERSE

FUNDAMENTAL

• The sun and the planets form the solar system. The sun is exactly at the center of our solar system and planets revolve all around the sun. The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
• All the planets move around the Sun in fixed paths called orbits.
• Mercury, Venus, Earth and Mars are called inner planets because they are close to the Sun. They are made of hard rock.
• Jupiter, Saturn, Uranus and Neptune are called outer planets as they are far away from the Sun. They are also known as gas giants.
• The movement of the earth about its axis is called rotation. It takes 24 hrs. to rotate once.
• The movement of the earth around the Sun in an orbit is called revolution. It takes about 365 days for the earth to complete one revolution around the Sun.
• Revolution of the earth causes changes in seasons.
• Moon is the earth’s natural satellite.
• Changes in the shape of the moon are called phases of the moon such as new moon, crescent moon, half moon, gibbous moon.
• The moon is made up of rocks and dust. There is no air on the moon. So, there is no life on the moon.
• Neil Armstrong was the first man to land on the moon in 1969.
• Shadow is formed when light is not able to pass through an opaque object. The Sun casts long shadows in the morning and evening, as the Sun is at the lowest in the sky. The Sun casts the shortest shadow at midday, when the Sun is highest in the sky.