Absolutely all bodies that have finite mass interact with each other due to the so-called gravitational force or gravity. We give the definition of gravity in the article, and also consider what role it plays in nature and space.
What is gravity or gravity?
In physics, the definition of gravity or gravity is given by the following: this is the force with which two bodies with mass are attracted to each other. This means that every person is attracted to any subject that he meets in his life. However, this force is so small that it is not felt.
The manifestation of gravity is noticeable when among the interacting bodies there is an object with a huge mass, for example, our planet. In many problems in physics, the definition of gravity reduces to the concept of attraction of objects to the Earth. In the latter case, they talk about body weight, which is calculated by the formula P = m * g. Here m and g are the mass of the body and the acceleration of gravity, which is approximately equal to 9.81 m / s 2 .
Sir Isaac Newton and gravity
For the first time, the great English scientist Isaac Newton gave an exhaustive definition of gravity at the end of the 17th century. He was able to combine the fragmented knowledge and empirical observations that existed at that time (Galileo's concept of the inertia of bodies and Kepler's laws) and put them in the form of a harmonious theory, called “Celestial Mechanics”.
According to Newton, all bodies are attracted to each other with the force, which is written by the following formula
F = G * m 1 * m 2 / R 2 , where
m 1 and m 2 are the masses of bodies,
R is the distance between them,
G = 6.674 * 10 -11 N * m 2 / kg 2 - universal gravitational constant.
The force of gravity (gravity) F acts at absolutely any distance, is directed to the center of mass of the bodies and rapidly decreases with increasing distance between them.
If we substitute the value for the mass and radius of the Earth into the marked formula, then we can obtain the acceleration g mentioned above.
Effects due to the existence of gravity
The definition of gravity was given above, but it was not said what role it plays in our lives. Firstly, due to its existence, we do not soar in the air, but stand firmly on the surface, and the air itself does not fly into outer space. Secondly, any thrown body falls back to the ground. Thirdly, when calculating the flight paths of free bodies, taking into account the influence of this force is fundamental. Finally, the force of gravity is the main factor that determines the features of the motion of our planet around the Sun, and in general the movement of any cosmic bodies.
Currently, scientists around the world are trying to combine gravity with other fundamental interactions to create a unified physical theory of our universe.