4th Class Science Our Universe Natural Phenomenon Related to Stars and Planets

         Natural Phenomenon Related To Planets and Stars

The natural phenomenon in the universe, which is associated with the heavenly bodies, like sun, earth, moon, etc., is spinning on their axis, an imagining line on which they spin.

           Rotation of Heavenly Bodies

When the axis of rotation lies within the body of the object itself, the body is said to rotate upon itself or spin. Most of the heavenly bodies in our galaxy like the planets, moon and the sun spin or rotate upon itself. This spin is better known as rotation. While rotating these bodies move around a central point called revolution. The process of revolution is not a property of planets alone. Moons also revolve with planet at its centre Sun and the other stars revolve around the centre of our galaxy. Our solar system has eight planets with their moons and the sun. The moon spic around itself while moving around their respective planets in their fixed orbit All the planets in a similar manner spin on their axis while they revolve around the sun Most of the planets in our solar system, including the earth spins in the same direction as they orbits the sun. The two exception to this are the planet venus and uranus.

Now let us look the effect of rotation and revolution on earth and its effect on us Te Earth spins around a line passing through its centre. Axis of earth is tilted at an angle of 23.5°. This titled imaginary line is called the axis o rotation. We all know that the rotation causes day and night. Earth completes one rotation in 24 hours. Thus our one day is 24 hours long. When the earth rotates on its axis, half of the earth faces the sun and it is day then that part. At the same time half of the earth which is away from the sun are dark and so that part has night time. This is the reason for the difference in the time across the world. When it is active day time in our country, people of America has night.

Rotation of the Earth around Its Axis  

         Revolution of Heavenly Bodies

Revolution is the movement of the earth around the sun in its fixed orbit. The time taken by the earth to complete one revolution is approximately 365.24 days. This is considered as 1 year. The revolution of the earth around the sun causes change in season. The main reason for the different seasons is the tilted axis on which the earth spins.

                 Showing the Revolution of the Earth  

Depending upon which hemisphere of the earth is closer to the sun and which one is farther we have summer and winter respectively. The half of the earth which gets more sunshine has summer while the other half has winter. This summer or winter lasts for six months and the situation reverses. There are situations when both the hemisphere are equidistant from the sun, then there is spring or autumn. Spring and autumn are pleasant time when it is neither very cold nor very hot. The path of the earth around the sun during revolution is an ellipse (elliptical orbit) rather than a circle and this is the reason why earth is closer to the sun sometimes and farther form it at other times. This is the cause of seasonal fluctuations.    

The Earth spins at 1,000 mph but it travels through space at an incredible 67,000 mph.

The moon weighs 81 billion tons.

More than 1 million earths would fit inside the sun.

A space vehicle must move at a rate of 7 miles per second to escape the earth's gravitational pull.

Star: Shines with its own light.

Planets: Do not have their own light.

Satellites: Object revolving around a planet. Moon is our natural satellite.

Eclipse: When view of one object is blocked by the shadow of the other.

Galaxies: Huge groups of stars in a define area of the universe.

Phenomenon related to the planets and stars: It is their movement around the central point and its axis.