|microgravity (mī'krō-grāv'ĭ-tē) Pronunciation Key
A condition in which an object in the gravitational field of some other body (such as the Earth) is accelerated freely as a result of the gravitational force. Free-falling objects, such as a skydiver or a satellite orbiting the Earth, are in a condition of microgravity, while objects held up by forces resisting gravity (as in the case of objects resting on the Earth's surface) or held up by aerodynamic forces (as in the case of birds or aircraft) are not. Since the normal experience of weight on Earth is the result of forces that resist gravity, objects in microgravity appear weightless. Not all effects of gravity are eliminated in such conditions; tidal forces, for example, still affect bodies in microgravity, especially large bodies such as the Earth and the Moon.
a measure of the degree to which an object in space is subjected to acceleration. In general parlance the term is used synonymously with zero gravity and weightlessness, but the prefix micro indicates accelerations equivalent to one millionth (106) of the force of gravity at Earth's surface. When microgravity (mug) is used as a unit of measure, a specific environment can be characterized as providing, for example, 20 mug (20 microgravities).
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