Stars and the Solar System

• Mercury: It is the nearest planet to the sun. It is the smallest planet of our solar system. It is very close to the sun so it is quite difficult to observe it. It has no satellite of its own.
• Venus: It is the Earth's nearest planetary neighbour. It is the brightest planet in the night sky. Sometimes it appears in the eastern sky before the sunrise, and sometimes in western sky just after the sunset. Thus it is also called morning or evening star. It has no satellite of its own.
• Jupiter: It is the largest planet of the solar system. It rotates very rapidly on its axis. It has a large number of satellites. It also has a faint ring around it.
• Saturn: Saturn lies beyond Jupiter; it contains beautiful rings around it which is not visible with the naked eye. It has a large number of satellites. It is least dense among all planets.

Outermost planet of solar system includes planets like Jupiter, Saturn, Uranus and Neptune.

• Uranus: It can be seen via telescope only. In its orbital motion it appears to roll on its side. It rotates from west to east.
• Neptune: It can be seen via telescope only. Neptune has a planetary ring system, though one much less substantial than that of Saturn.

Group of stars having a recognisable shape is called constellation. Constellation is an internationally defined area of celestial sphere. For example: Ursa Major, Orion etc.

Ursa Major can be seen in the sky during summer time in the early part of the night, it is also known as Big Dipper or Saptarashi. There are seven prominent stars in this constellation; it appears like a big question mark or ladle.

Orion can be seen in the sky during winter in the late evenings. It has seven or eight stars. The brightest star Sirius is located close to the Orion.

Cassiopeia is a constellation that can be seen in the northern sky. It is visible during winter in the early part of night. It looks like distorted letter W or M.