Free Fall in General Relativity
In GR, an object in free fall is subject to no force and is an inertial body moving along a geodesic. Far away from any sources of space time curvature, where spacetime is flat, Newtonian theory of free fall agrees with GR but otherwise the two disagree. The experimental observation that all objects in free fall accelerate at the same rate, as noted by Galileo and then ambodied in Newton's theory as the equality of gravitational and inertial masses, and later confirmed to high accuracy by modern forms of the Eötvös experiment, is the basis of the Equivalence Principle, from which basis Einstein's theory of general relativity initially took off.
Read more about this topic: Freefall
Famous quotes containing the words free, fall, general and/or relativity:
“I don’t know how long it has been since my ear has been free from the roll of a drum. It is the music I sleep by, and I love it.... I shall remain here while anyone remains, and do whatever comes to my hand. I may be compelled to face danger, but never fear it, and while our soldiers can stand and fight, I can stand and feed and nurse them.”
—Clara Barton (1821–1912)
“Compassion is frequently a sense of our own misfortunes, in those of other men; it is an ingenious foresight of the disasters that may fall upon us hereafter. We relieve others, that they may return the like when our occasions call for it; and the good offices we do them are, in strict speaking, so many kindnesses done to ourselves beforehand.”
—François, Duc De La Rochefoucauld (1613–1680)
“A private should preserve a respectful attitude toward his superiors, and should seldom or never proceed so far as to offer suggestions to his general in the field. If the battle is not being conducted to suit him, it is better for him to resign. By the etiquette of war, it is permitted to none below the rank of newspaper correspondent to dictate to the general in the field.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)
“By an application of the theory of relativity to the taste of readers, to-day in Germany I am called a German man of science, and in England I am represented as a Swiss Jew. If I come to be regarded as a bête noire the descriptions will be reversed, and I shall become a Swiss Jew for the Germans and a German man of science for the English!”
—Albert Einstein (1879–1955)