The gravity field is the field of force, caused by the gravitation of the Earth, and influenced by the Earth rotation, the atmosphere and by geological bodies. In physics, as defined by Asimov, a force is that which can impose a change of velocity on a material body. ... This article covers the physics of gravitation. ...

The field can be described by several observationables like

• scalar of the gravity - at the surface from 9,78 up to 9,83 m/s², see gravimetry and geophysics
• direction of the vertical - with vertical deflections from 2" up to 50" in the mountains, see geodetic astronomy and geodesy
• the surface of the geoid
• gravity gradients - see Roland Eötvos and gradiometry
• levelling - see trigonometry and surveying
• potential differences - see potential theory and height systems.

The last developments of Astronautics has caused a higher interest in the gravity field of other celestial bodies, too - e.g. of the planet Mars and some asteroids like Eris or Ida, and on a theoretical basis also on stars or extreme masses like black holes, and in the theories of cosmology. Gravitation is the tendency of masses to move toward each other. ... Gravimetry is the measurement of gravitational force, weight, or density. ... Geophysics, the study of the earth by quantitative physical methods, especially by seismic reflection and refraction, gravity, magnetic, electrical, electromagnetic, and radioactivity methods. ... An object is in a vertical position when it is aligned in an up-down direction, perpendicular to the horizon. ... The vertical deflections (deflections of the plumb line, astro-geodetic deflections) are important parameters of the local gravity field. ... Mount Cook, a mountain in New Zealand A mountain is a landform that extends above the surrounding terrain in a limited area. ... This article or section should include material from Geodetic datum. ... A geoid is a close representation, physical model, of the figure of the Earth. ... In construction, level (as an adjective) is to horizontal what plumb is to vertical. ... Trigonometry (from the Greek trigonon = three angles and metro = measure) is a branch of mathematics dealing with angles, triangles and trigonometric functions such as sine, cosine and tangent. ... Surveying is concerned with the application of mathematics and physics in obtaining accurate measurements for the determination of the position of points on the Earths surface. ... In physics, a potential is a scalar quantity that can be used to analyze the effects of complicated vectorial forces and similar quantities by means of simple conservation laws. ... Potential theory may be defined as the study of harmonic functions. ... Astronautics is the branch of engineering that deals with machines designed to work outside of Earths atmosphere, whether manned or unmanned. ... Mars, with polar ice caps visible. ... An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... The Pleiades star cluster A star is any massive gaseous body in outer space, just like the Sun. ... An artists impression of a black hole with a closely orbiting companion star that exceeds its Roche limit. ... Look up Cosmology in Wiktionary, the free dictionary For the jazz band, see: Cosmology (band) Cosmology, from the Greek: κοσμολογία (cosmologia, κόσμος (cosmos) world + λογια (logia) discourse) is the study of the universe in its totality and by extension mans place in it. ...

See also

• Astronomy
• Geosciences
• Planetology
• Electro-optics
• Tacheometer
• Space techniques