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:
“What our children have to fear is not the cars on the highways of tomorrow but our own pleasure in calculating the most elegant parameters of their deaths.”
—J.G. (James Graham)
“I work all day, and get half-drunk at night.
Waking at four to soundless dark, I stare.
In time the curtain-edges will grow light.
Till then I see what’s really always there:
Unresting death, a whole day nearer now,
Making all thought impossible but how
And where and when I shall myself die.”
—Philip Larkin (1922–1986)
“Keep on adding, keep on walking, keep on progressing: do not delay on the road, do not go back, do not deviate.”
—St. Augustine (354–430)