gravitational field

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variation in Earth's gravitational field

gravitational field

physics

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variation in Earth's gravitational field — variation in Earth's gravitational field The variation in the gravitational field, given in milliGals (mGal), over the Earth's surface gives rise to an imaginary surface known as the geoid. The geoid expresses the height of an imaginary global ocean not subject to tides, currents, or winds. Such an ocean would vary by up to 200 meters (650 feet) in height because of regional variations in gravitation.

A gravitational field is a region of space where a mass experiences a force due to the presence of another mass. This concept is central to understanding gravity, which governs the large-scale behavior of the universe.12

Newtonian Gravity

Historically, Isaac Newton described gravity as a force acting directly between any two objects with mass. His law of gravitation states that this force is proportional to the product of their masses and inversely proportional to the square of the distance between them: (F = G\frac{m_1m_2}{R^2}).3

Field Theory and General Relativity

Modern physics, particularly Albert Einstein's theory of general relativity, views gravity not as a force but as a geometric property of space-time. In this framework, mass curves space-time, and objects follow the paths (geodesics) created by this curvature. This field theory approach is consistent with special relativity, which states that information cannot travel faster than the speed of light. Gravitational fields can also radiate energy as waves, as detected by observatories like LIGO.415

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Earth
Basic planetary data
Earth’s gravitational field (see gravitation) is manifested as the attractive force acting on a free body at rest, causing it to accelerate in the general direction of the centre of the planet. Departures from the spherical shape and the effect of Earth’s rotation cause gravity to…
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Earth’s gravitational field (see gravitation) is manifested as the attractive force acting on a free body at rest, causing it to accelerate in the general direction of the centre of the planet. Departures from the spherical shape and the effect of Earth’s rotation cause gravity to…
Read More

radiation
The field concept
As one example, a gravitational field exists around the Earth and indeed around every particle of mass that moves with it. At every point in space, the field has direction in respect to the particle. The strength of the gravitational field around a specific particle of mass, m, at…
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As one example, a gravitational field exists around the Earth and indeed around every particle of mass that moves with it. At every point in space, the field has direction in respect to the particle. The strength of the gravitational field around a specific particle of mass, m, at…
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Saturn
The interior of Saturn
…is obtained from studying its gravitational field, which is not spherically symmetrical. The rapid rotation and low mean density that lead to distortion of the planet’s physical shape also distort the shape of its gravitational field. The shape of the field can be measured precisely from its effects on the…
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…is obtained from studying its gravitational field, which is not spherically symmetrical. The rapid rotation and low mean density that lead to distortion of the planet’s physical shape also distort the shape of its gravitational field. The shape of the field can be measured precisely from its effects on the…
Read More

plasma
Regions of the Sun
…of plasma in the Sun’s gravitational field had one solution that allowed the gas to become supersonic and to escape the Sun’s pull. The solution was much like the description of a rocket nozzle in which the constriction in the flow is analogous to the effect of gravity. Parker predicted…
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…of plasma in the Sun’s gravitational field had one solution that allowed the gas to become supersonic and to escape the Sun’s pull. The solution was much like the description of a rocket nozzle in which the constriction in the flow is analogous to the effect of gravity. Parker predicted…
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celestial mechanics
Tidal evolution
However, the gravitational field of one body in close orbit about another will tidally distort the shape of the other body. Dissipation of part of the energy stored in these tidal distortions leads to a coupling that causes secular changes (always in the same direction) in the…
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However, the gravitational field of one body in close orbit about another will tidally distort the shape of the other body. Dissipation of part of the energy stored in these tidal distortions leads to a coupling that causes secular changes (always in the same direction) in the…
Read More