We explain what the force of gravity is, how and by whom it was discovered. Also, some examples of this force.
What is the force of gravity?
The force of gravity (or simply “gravity”) is one of nature's fundamental interactions which causes bodies with mass to attract each other with greater intensity to the extent that they are more voluminous or closer to each other. The principle that governs this interaction is known as “gravitation” or “gravitational interaction”, and responds in physics to what is described by the Law of Universal Gravitation.
This is the same attraction that the Earth exerts on bodies and objects that are close to it, including us, and that makes things fall. Also determines the movements of the space stars (planets orbiting the Sun or moons and artificial satellites orbiting said planets in turn.
Unlike the other fundamental interactions in the Universe (which are the strong and weak nuclear forces, and electromagnetism), the force of gravity predominates inexplicably over enormous distances while the others occur over much shorter distances.
Gravity is studied in different theoretical frameworks depending on whether it is a mechanical (classical) or relativistic approach.
Usually the units used to work with gravity are units of weight such as kilograms of force, or Newtons (N). This is because the weight of a body is equal to its mass times the acceleration of gravity that the Earth's gravitational force exerts on it. That is, gravity should not be confused with gravitational force. Gravity is an acceleration and not a force like weight.
The acceleration of gravity on the Earth's surface reaches about 9.80665 m/s2.
Who discovered the force of gravity?
The force of gravity was not properly “discovered”, since its effects have been known since the beginnings of humanity and thought. However, the Law of universal gravitation which explains it and allows it to be calculated was proposed by Isaac Newton in 1687, supposedly after being hit on the head by an apple while resting in the English countryside.
This episode would have revealed to the English scientist that the same force that makes things fall to the ground, keeps the planets in their orbit with respect to the Sun and their satellites with respect to them. This was a turning point in the history of modern physics.
Later, the physicist Albert Einstein in the 20th century, based on Newton and his own findings, postulated his General Relativity Theoryin which he reformulated some aspects of Newtonian gravitation.
Thus a new perspective on gravity was inaugurated, called “relativistic.” According to her, gravity is not a universal measure of force, but a variable one, and it affects not only space but also time.
Examples of the force of gravity
The force of gravity can be studied in the following examples:
- The free fall of a body on the Earth's surface The mass of the planet attracts us to it and acts on our mass, creating an acceleration. Therefore, an object that falls for one minute has a stronger impact than one that falls for one second.
- An object thrown into the sky A cannonball, for example, will fly in a straight line until it suffers a loss of acceleration, resulting from the force of gravity, curving its trajectory. When this exceeds the initial force of the explosion, the object will fall and stop moving.
- The orbit of the moon around our planet This movement is due to the fact that the moon is trapped in the Earth's gravitational field, at such a distance that it cannot move away in a straight line, nor can it collapse towards us and fall.
- The fall of meteorites Attracted by their enormous force of gravity, many meteorites enter the atmosphere of Jupiter, Saturn and other very massive planets, torn from their natural orbit around the Sun.
