# Why gravity?

WHY GRAVITY?

Science is all about curious observations and the related experiments. Have you wondered, why is going uphill lot more tiring than going downhill? One of the long standing goals of physics is to understand the gravitational force- the force that holds you and me to earth. This force also reaches out through our milky way galaxy,holding together billions of stars in the galaxy and the countless molecules and particles between stars.

HISTORICAL INTRODUCTION People have always observed the movements of moon, planets, stars and other celestial bodies for thousands of years. The earliest model for planetary motion was geocentric model which was proposed stating that all the celestial bodies, stars,the sun and the planets all revolve around the earth which was regarded as the center of the universe. For about 1400 years,this model was widely accepted. Later it was Nicolas Copernicus who suggested and proposed that the earth and other planets revolved around the sun in circular orbits. It was Johannes Kepler who proposed the three laws of planetary motion by the name of Kepler's laws of planetary motion. Later it was Sir Isaac Newton who did the great achievement by proposing the universal law of gravitation.

Here are some reasons why gravity is interesting and necessary: Gravity will actually affect you more or less depending on the mass of the planet you are standing on.

In order to escape the earths gravity you would need to be travelling at seven miles per second,known as earth's escape velocity.

Gravity varies even on different parts of earth,that is mainly because earth is not a perfect sphere and it's mass is unevenly distributed.

Any objects that has mass right from the smallest grain to the biggest star in the sky has gravity.

Gravity is just one of four universal forces and it's actually very weak.

As you accelerate, you will be able to experience the larger effect of gravity.

In the absence of air resistance, all the objects falling down to earth due to gravity have the same speed.

If the sun disappeared right now, it would take eight minutes for us to realize it till the gravitational waves finally stops hitting us.

GRAVITY is a necessary and not an evil.