What is a gravitational field?
We explain what gravitational fields are and how to measure their intensity. Examples of gravitational field.
The Moon orbits our planet by the gravitational forces of the Earth’s mass.
The gravitational field or gravitational field is the set of forces that represent, in physics, what we commonly call the force of gravity: one of the four fundamental forces of the universe, which tends to attract the masses of matter to each other.
According to the logic of gravitational fields, the presence of a body of mass M will subject the space around it to gravitational forces, altering the properties (the trajectory, for example) of everything around it.
In fact, if another body of mass m approaches the gravitational field of M, we will notice that its movement is altered by the force of gravity.
And, according to the theory of relativity, even time itself would be affected by such forces, distorting it and giving rise to singularities such as black holes, astronomical objects whose gravitational fields are so strong that not even light can escape them.
Gravitational fields were for many years eminently theoretical in nature, understood by classical physics (Newtonian) as a vector field, and by relativistic physics as a second order tensor field, but the discovery in 2016 of gravitational waves by the scientists of the LIGO experiment seems to shed new light on this matter.
Gravitational field strength
Intensity is commonly defined as the force per unit mass.
The intensity of the gravitational fields or, in other words, the acceleration of gravity (or simply gravity) is represented in classical physics by the symbol g and as a field of vectors, i.e. lines with sense and direction.
It is commonly defined as the force per unit of mass that a given particle will experience in the presence of a mass distribution. It is usually expressed in Newtons per kilogram (N/kg).
The formula for your calculation, then, would be:
g = lim m→0 F/m, where m would be a test mass and F the gravitational force acting on it.
The gravitational potential of a gravitational field is, in Newtonian mechanics, a scalar magnitude measured in joules per kilogram (J/kg), which is defined as the amount of work per unit of mass required to transport a body at a constant velocity from infinity to a given point in the gravitational field in question.
The gravitational potential is calculated on the basis of the following formula:
V = – GM/r, where V is the gravitational potential, G is the universal gravitational constant and r is the distance from the determined point of the gravitational field to which the mass M is displaced.
Examples of gravitational field
An example of a gravitational field are the planets orbiting around the sun.
A perfect example of a gravitational field is the solar one, that is, the one presented by our planetary system, in which the planets orbit around the sun, attracted by the gravitational forces of its mass.
Another possible example is the Earth’s own gravitational field, which we can feel every time we drop an object on the ground.
Compared to our size, the Earth’s mass of 5974 x 1024 kg is so massive that the properties of its field are difficult to pinpoint with the naked eye.
However, the Earth’s gravity is estimated to be about 9.8 N/kg, i.e. an acceleration of 9.8m/s.
The Earth’s gravity is estimated to be about 9.8 N/kg, i.e. an acceleration of 9.8m/s. This value can oscillate minimally depending on the geographic location, but in general it presents that value and tends towards the very center of the Earth.
Likewise, the gravitational field will be more intense in the vicinity of the Earth’s surface than in the outer layers of the atmosphere.