- Books Name
- Class-8 Science Book
- PathSet Publications
- CBSE Class 8
Some Other Members of the Solar System
- Like other planets, there are certain celestial bodies that are found in the solar system. Asteroids are small rock-like objects that are found orbiting the sun.
- They are generally found between the orbits of Mars and Jupiter. This region is also called the Asteroid belt. However, asteroids can also be found in other places in the solar system.
- Comets are big pieces of ice and rock that also revolve around the sun in elliptical-shaped orbits.
- Comets are the leftover pieces of rocks that were formed at the time when the solar system was beginning its formation.
- Comets are often observed to have a tail. This tail appears as a comet approaches the sun.
- At that time, dust and gas are discharged from the comet due to the heat of the sun. Since the comet is approaching the sun, the tail of the comet is always in the opposite direction of the sun.
- As the distance between the sun and the comet increases the size of the tail of the comet also increases.
- Since comets revolve around the sun they can be viewed at periodic times from the Earth.
- For example, Halley's Comet appears after every 76 years. It was last viewed in 1986.
Meteoroids and Meteors
- The asteroids in space sometimes collide with each other and form meteoroids. Hence the small pieces of an asteroid can be called meteoroids.
- From these meteoroids, meteors are formed.
- When a meteoroid enters the atmosphere of the Earth it appears as a streak of light in the sky or a meteor. The Meteors generally have high speed as they enter the atmosphere. Thus, they get heated up due to the friction of the atmosphere.
- Hence the meteors light up as a streak of light. However, they get evaporated in the sky before reaching the Earth's surface and this streak of light is therefore visible for a short period only.
- Meteors are also called shooting stars because of their characteristic feature however they are not stars but just a piece of rock.
- When the earth crosses a comet's tail a large number of flying meteors can be observed in the sky. This is called a Meteor shower. Certain meteor showers occur periodically in the sky.
- These are the man-made satellites that are sent out into space to revolve around the earth. They orbit nearer to the earth as compared to the moon. Functions of artificial satellites:
- Weather forecasting
- Transmission of signals of radio and television
- Remote-sensing - acquiring information about an object from a distance, for example, the artificial satellite can acquire information about the earth from a distance
- Telecommunication - transmission of information using radio signals and electromagnetic systems.
Some Indian Artificial Satellites of the Earth:
How artificial Satellite is different from a Natural Satellite?