Calculating Time Delay
In a near-static gravitational field of moderate strength (say, of stars and planets, but not one of a black hole or close binary system of neutron stars) the effect may be considered as a special case of gravitational time dilation. According to special relativity, the speed of light is constant for measurements in a local reference frame. However, this is not true for non-local paths along which a gravitational field is present. 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 near-static fields the difference is directly proportional to the classical gravitational potential, precisely as given by standard gravitational time dilation formulas.
Read more about this topic: Shapiro Delay
Famous quotes containing the words calculating, time and/or delay:
“Sin in this country has been always said to be rather calculating than impulsive.”
—Frank Moore Colby (1865–1925)
“Grief thief of time crawls off....”
—Dylan Thomas (1914–1953)
“Once we began to see our images
Reflected in the mud and even dust,
‘Twas disillusion upon disillusion.
We were lost piecemeal to the animals,
Like people thrown out to delay the wolves.
Nothing but fallibility was left us....”
—Robert Frost (1874–1963)