term "gravitational field" appeared in physics at once.First, this type of interaction is considered under the law of universal gravitation.The modern term came much later.There is a concept for centuries.
under gravity to understand the nature of bodies mutually attracted, and the property itself is associated with the weight of the bodies.Today in physics, gravity is considered as the curvature of space-time near massive bodies.
bodies create force fields around it.The intensity of the gravitational field at any point characterizes the force which acts on another body at that particular point.This strength of the gravitational field g is the ratio of force F, acting on the body of a certain mass m, the weight of the body in the gravitational field.
The field strength coincides with the direction, magnitude and units of measurement with the known acceleration of gravity, but in the physical sense is a different size.The field strength characterizes the state space at a certain point, and acceleration, and appear only when the power at this point is the body.
Newton in 1687 found that two bodies attract with a force directly proportional to the square of the distance at which they are to each other.This conclusion was made on the basis of their experience of the laws of planetary motion.
The gravitational field is a type of physical field, through which the attraction of bodies (gravitational interaction).This may be an interaction between the planets of the solar system, the planets and their satellites, the Earth and the bodies near it.
Earth's gravitational field is a force field, which is due to the attraction of its weight and the centrifugal force arising as a result of Earth's rotation.It is dependent (though slightly) from the attraction of the moon, sun and other bodies, and mass of the earth's atmosphere.
The gravitational field of the planet is characterized by the force of gravity, and the potential number of different derivatives.Part of the building is called the geopotential (it is due only to the attraction of the Earth).In order to address the various challenges it is presented as a series of functions (spherical).
The gravitational field of the Earth consists of two parts, which are called normal and abnormal.The first is basic, it corresponds schematized model of the planet, is depicted as an ellipsoid of revolution.It is consistent with the real planet.The anomalous part of the value is less, and measured a very complex way.Once the position of the moon and sun relative to Earth is constantly changing, it happens occasionally and the variation of its gravitational field.This contributes to the tidal deformations of the Earth, including causes tides.
In addition, there are tidal changes in the Earth's gravitational field arising from mass redistribution in the depths of earthquakes, tectonic movements, movement of water and air masses, volcanic eruptions, changes in the instantaneous axis of rotation of the Earth per day, as well as its angular velocity.Many of the magnitude of such changes can not be observed, so they are measured only in theory.
Earth's gravitational field is the basis for the determination of the geoid, which is characterized by gravimetric figure of the Earth.In this figure, set the height of the surface of the planet.In the gravitational field of a conclusion on the state of hydrostatic equilibrium of the planet and arising from this tension in its depths, explore the elastic properties of the Earth.
Earth's gravitational field helps to make calculations of the orbits of satellites, trajectory of the missile.Anomalies in the field to help recognize the distribution of density inhomogeneities in the crust, upper mantle, tectonic zoning of conduct to seek minerals.
