An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 2 Search : dilation
dilation
  فراخش   
farâxeš (#)

Fr.: dilatation   

The act of dilating; state of being dilated. Also dilatation.
Physics: The increase in volume per unit volume of a homogeneous substance. → time dilation.

Verbal noun of → dilate.

time dilation
  فراخش ِ زمان   
farâeš-e zamân

Fr.: dilatation du temps   

A phenomenon related to special and general relativity.
1) In → special relativity, the apparent shortening of time that occurs at speeds approaching that of light. A clock moving relative to a stationary observer will appear to slow down by a factor √(1- v2/c2), where v is the velocity and c the speed of light. → twins paradox.
2) In → general relativity, a clock in a stronger gravitational field runs more slowly. The dilation factor is given by: √(1- 2GM/rc2), where G is the gravitational constant, M the mass of the object creating the gravitational field, r a radial coordinate of the observer, which is analogous to the classical distance from the center of the object, and c the speed of light.

time; dilation, verbal noun of dilate, from M.E. dilaten, from O.Fr. dilater, from L. dilatare "make wider, enlarge," from → dis- "apart" + latus "wide."

Farâxeš, → dilation; zamân, → time.