Gravity

We explain what gravity is and how this constant of nature can be measured. Also, its units and some examples.

Gravity
The Law of Universal Gravitation was formulated by Isaac Newton in 1687.

What is Gravity?

Gravity or force of gravity is a phenomenon of nature by which bodies that have mass attract each other reciprocally with greater intensity the more massive these bodies are. It is one of the four fundamental interactions of matter, and is also known as “gravitation” or “gravitational interaction.”

This attraction is what planet Earth exerts on all objects on it, and causes things to fall. But it can also be observed among space stars, such as the planets that orbit the Sun (attracted by its gravity) or meteorites that are attracted by the mass of our plane and end up disintegrating in the atmosphere.

The general law of physics that governs gravitational action is (in classical mechanics) the Law of Universal Gravitation, formulated by Isaac Newton in 1687. In it the English scientist explains that the same gravity that makes things fall to the ground is the that keeps the planets in their orbit with respect to the Sun.

Much later, in the 20th century, the physicist Albert Einstein postulated his Theory of General Relativity, in which he reformulated certain aspects of gravitation and inaugurated a new perspective on the phenomenon: the relativistic one, according to which gravity would not only affect the space, but time.

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Unlike the other fundamental interactions in the Universe, gravity appears to be the predominant force over great distances (the other three occur at much more immediate distances), responsible for the movement of the celestial bodies and for many interactions of stellar matter.

How is gravity measured?

The force of gravity is measured in relation to the acceleration it imparts on the objects on which it acts, as long as no other forces intervene. This acceleration has been calculated, on the Earth's surface, at about 9.80665 m/s2.

On the other hand, the gravitational force can be measured through different formulas depending on the specific physical approach (classical or relativistic mechanics), and is usually represented, like other forces, in kilograms of force or in Newtons (N).

Gravity measurement units

As we said just now, gravity It is usually measured in Newtons (N) when we refer to the gravitational force, and in m/s2 when we talk about the acceleration caused by the attraction of a massive body on another with a smaller mass. An example is the acceleration caused by the Earth on an object that is dropped.

Examples of gravity

Gravity
An example of the force of gravity could be the planets that revolve around the sun.

Some examples that confirm the action of the force of gravity are the following:

  • The acceleration presented by an object in free fall, as we said before: when the gravitational force due to the Earth acts on it, the speed at which it moves increases progressively over time.
  • The opposite case: an object thrown with all our strength in a straight line will suffer a slowdown in its movement due to the gravitational force that acts in the direction of the center of the Earth, and which ends up forcing it to fall freely.
  • The orbit of the planets around larger stars, such as the planets around the Sun, or the moons and natural satellites around the planets. This is the case with our own planet and our moon, for example.
  • Meteorites that approach or collide even with the Earth or other planets do so attracted by their large masses.
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