Stars and the Solar System
Solar System
It consists of the Sun, the eight Planets and their Satellites (or moons), and millions of smaller celestial objects such as Asteroids, Comets and Meteoroids.
Planets- Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
The gravitational force of the Sun keeps the Solar system together and controls the movements of planets and other members of the Solar System.
Stars
Star is a luminous body because it can emit its own light.
We can see them in night only because during day, the light of the sun is so intense that it becomes difficult to see them.
We have a star named Pole star. It is also called a stationary star because it does not move and it is the brightest star. It is situated on the axis of earth that is why it appears immovable.
Constellations
The stars forming a group that has a recognizable shape is called a constellation.
Different types- Ursa Major, Ursa Minor, Orion, Scorpius, Cassiopeia, Leo Major, Pleiades.
The shapes of constellations resemble objects familiar to those people.
Satellites
Natural Satellites
Artificial Satellites
Light year
The distance travelled by light in one year.
Astronomical unit
The average distance between the Earth and the Sun.
Asteroids
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.
Comets
Comets are also members of our solar system. They revolve around the Sun in highly elliptical orbits.
Meteors and Meteorites
A meteor is usually a small object that occasionally enters the earth’s atmosphere.
When a piece of meteoroid that makes it to the surface of the earth is called a meteorite.