Search results
Results from the WOW.Com Content Network
Gravitational time dilation is a form of time dilation, an actual difference of elapsed time between two events, as measured by observers situated at varying distances from a gravitating mass. The lower the gravitational potential (the closer the clock is to the source of gravitation), the slower time passes, speeding up as the gravitational ...
A more explicit description can be given using tensors. The crucial feature of tensors used in this approach is the fact that (once a metric is given) the operation of contracting a tensor of rank R over all R indices gives a number — an invariant — that is independent of the coordinate chart one uses to perform the contraction. Physically ...
In 1964, Pound and J. L. Snider measured a result within 1% of the value predicted by gravitational time dilation. [36] (See Pound–Rebka experiment) In 2010, gravitational time dilation was measured at the Earth's surface with a height difference of only one meter, using optical atomic clocks. [26]
The measured elapsed time of a light signal in a gravitational field is longer than it would be without the field, and for moderate-strength nearly static fields the difference is directly proportional to the classical gravitational potential, precisely as given by standard gravitational time dilation formulas.
To calculate the changes in frequency in a nearly static gravitational field, only the time component of the metric tensor is important, and the lowest order approximation is accurate enough for ordinary stars and planets, which are much bigger than their Schwarzschild radius.
Derivation of Newton's law of gravity Newtonian gravitation can be written as the theory of a scalar field, Φ , which is the gravitational potential in joules per kilogram of the gravitational field g = −∇Φ , see Gauss's law for gravity ∇ 2 Φ ( x → , t ) = 4 π G ρ ( x → , t ) {\displaystyle \nabla ^{2}\Phi \left({\vec {x}},t ...
It is characterized by a length scale r s, known as the Schwarzschild radius, which is defined by the formula = where G is the gravitational constant. The classical Newtonian theory of gravity is recovered in the limit as the ratio r s / r goes to zero.
where the numerator is the gravitational, and the denominator is the kinematic component of the time dilation. For a particle falling in from infinity the left factor equals the right factor, since the in-falling velocity v {\textstyle v} matches the escape velocity c r s r {\textstyle c{\sqrt {\frac {r_{\text{s}}}{r}}}} in this case.