Chapter Review:

• The stars, the planets, the moon and many other objects in the sky are called celestial objects.

• The day on which the whole disc of the moon is visible is known as the full moon day.

• The various shapes of the bright part of the moon as seen during a month are called phases of the moon.

• On the fifteenth day the moon is not visible. This day is known as the new moon day.

• The next day of the new moon day, only a small portion of the moon appears in the sky. This is known as the crescent moon.

• The distance travelled by light in one year known as light year.

• The stars forming a group that has a recognisable shape is called a constellation.

• A body revolving around another body is called a satellite.

• A planet has a definite path in which it revolves around the Sun. This path is called an orbit.

• The movement of planets around the sun on their orbit is called revolution. 

• The planets move on their own axis like top, Such movement s known as rotation. 

• Mars appears slightly reddish and, therefore, it is also called the red planet.

• Moon revolving round the Sun.

• The smallest planet is mercury.

• The mass of Jupiter is about 318 times that of our Earth.

• On July 21, 1969 (Indian time) the American astronaut Neil Armstrong
  landed on the moon for the first time.

• There is a large gap in between the orbits of Mars and Jupiter. This gap is occupied by a large number of small objects that revolve around the Sun. These are called asteroids.

• However we may see a bright streaks of light falling in the sky. These are commonly known as shooting stars, although they are not stars. They are called meteors.

• The Sun is nearly 150,000,000 kilometres (150 million km) away from
  the Earth.

• The artificial satellites revolve around the Earth. They are much closer than the moon.

• Venus is the brightest planet in the night sky.