We’ve finished three of the four forces that make up the universe in last article. So now we can look at the fourth and talk about big things. In the case of physics, this force considers being weak. These forces are the equations of the interactions between atomic particles of size Ignore. One reason for this is that gravity positively correlates with the mass of the objects it is operating on.

## 04. Gravity

At present, particles such as electrons are approximately ‘massless’ particles, so this force is approximately zero between them.

That is, even if the force of gravity attracts two electrons, the gravitational force is negligible compared to the electromagnetic interaction we saw in the previous article.

The largest objects in the universe are galaxies.They have billions of massive stars, planets, cosmic gases, and dust. In spite of the large gap between the two galaxies, the intermediate gravitational pulling causes one to collide.

Gravitational force is the invisible force that attracts the two objects. All masses of matter have gravitational potential.

To calculate the force of gravity acting on an M1 object and M2 at a distance R,

#### F=G M1M2 / (R*R)

G = gravity constant.

Before the time of Galileo, scholars believed that the weight of an object would change with the speed of the drop.

(When a stone is left with a bird’s feather, the stone rapidly falls to the ground, and the feather slows due to the atmospheric constraint.)

That is, the rock and the bird are drawn to the earth in the same ‘acceleration’ (G). The acceleration is the ratio of both the force and the mass of the object. That is,** F = ma. **This is Newton’s second law.

As the mass (m) increases, the force (F) increases, but the acceleration (a) remains the same.

This is the most important law of physics.

To understand how practical this is, let me tell you an easy way to measure the depth of a pit using the Newtonian law of everyday life.

#### S = ut + ½ at2

This is called the Newtonian equation of motion. Whenever a constant force is acting on an object, the motion of the object can calculates using the kinetic equation mentioned above, and the distance past that object.

“S” is the distance that the object moves at a specified time interval, and “a” is the constant acceleration of the object.

Now, let’s see how we can measure the depth of a deep hole in just two or three minutes using only a handheld cell phone. This acceleration, due to gravity, calls (g).

g = 9.8 meters / second ^ 2. This acceleration (g) unchanged on the surface of the earth. The reason for our body weight is that the acceleration does not change much at a depth of the surface. More importantly, we drop the stone into the well. Since we do not throw the stone, its initial velocity is “u” 0 (zero). Initial velocity (u = 0) is the Newtonian equation “ut = 0”. The equation we need is S = ½ gt ^ 2. The stone that is left out of the mouth (a black stone does not work in the son a small pebble will disappear because the weight will increase in mass). For example, if it took 2.2 minutes to fall to the bottom of the stone, for example, the distance that the stone passed over this period, ie, the “s” is the depth of the hole

s = 1/2 * 9. 8 * (2. 37) 2 = 27.52 meters. So the depth of the hole I measured is 27.5 meters or 80 feet. Our measurement capability (using only the eye and ear) is limited but at a more accurate value. We can get the answer.

We know that Newton and Einstein have explained gravity from two angles. He said that not only the apple but the apple also attracts the earth.

Now you have a little understanding of Newtonian gravity. Let’s take a brief look at Einstein’s gravity now.

For this, we must also consider the fourth dimension, which we never thought of. This fourth dimension is nothing else. It is time to comfort us, sometimes to make us miserable.

Einstein said that not only the space around us but space and time are colliding with time. That, according to Newton, time and space are constants that do not affect.

But after Einstein’s arrival, it became clear that objects could change space and time. Einstein claims to have asked two questions about gravity.

## Why does gravity always attract objects? Why not repel?

If we change the distance between two objects, the gravitational force between them must change immediately … that is, gravity must move at an infinite speed. “It is not a force. It is a ‘crater’ in the space around which heavy objects like the earth are,” he said.

According to Newton’s first law, an object moves along a rigid line until it exerts a force on it or stays at rest.

The speed at which the Earth throws from the sun at that moment, at the same speed, at this moment, in a raging line !!! Because there is no external force to stop it, but because of its large mass, the sun is creating space around it. The Earth has been rotating in a straight line for 4.543 billion years.

Some scientists say that humans will never be able to see or understand the nature of the real universe.

The illumination of indirect time is also indirect. The light left here will reappear millions of years back here.

The biggest challenge for physicists today is to combine these four forces to formulate a fundamental law and discover the secret of the universe.

The reason is in the next article.