Å·±¦ÓéÀÖ

“Dear Habicht, / Such a solemn air of silence has descended between us that I almost feel as if I am committing a sacrilege when I break it now with some inconsequential babble... / What are you up to, you frozen whale, you smoked, dried, canned piece of soul...?”
― Albert Einstein, Relativity: The Special and the General Theory

“If you've never done anything wrong it's probably because you have never tried anything new.”
― Albert Einstein, Relativity: The Special and the General Theory

“result: every description of events in space involves the use of a rigid body to which such events have to be referred. The resulting relationship takes for granted that the laws of Euclidean geometry hold for ‘distancesâ€�, the ‘distanceâ€� being represented physically by means of the convention of two marks on a rigid body.”
― Albert Einstein, Relativity: The Special and the General Theory

“Silence is the hardest scream”
― Einstein Albert 1879-1955, Relativity; The Special and General Theory

“The struggle, so violent in the early days of science, between the views of Ptolemy and Copernicus would then be quite meaningless. Either CS [coordinate system] could be used with equal justification. The two sentences, “the Sun is at rest and the Earth moves,â€� or “the Sun moves and the Earth is at rest,â€� would simply mean two different conventions concerning two different CS.”
― Albert Einstein, The Evolution of Physics: From Early Concepts to Relativity and Quanta

“if, relative to K, Kâ€� is a uniformly moving co-ordinate system devoid of rotation, then natural phenomena run their course with respect to Kâ€� according to exactly the same general laws as with respect to K. This statement is called the Principle of Relativity (in the restricted sense).”
― Albert Einstein, Relativity: The Special and the General Theory

“Fundamental ideas play the most essential role in forming a physical theory. Books on physics are full of complicated mathematical formulae. But thought and ideas, not formulae, are the beginning of every physical theory.”
― Albert Einstein, The Evolution of Physics: From Early Concepts to Relativity and Quanta

“of the actual objects of physical reality. Physical objects are not in space, but these objects are spatially extended.”
― Albert Einstein, Relativity: The Special and the General Theory

“He might also interpret his experience thus: “My body of reference (the carriage) remains permanently at rest. With reference to it, however, there exists (during the period of application of the brakes) a gravitational field which is directed forwards and which is variable with respect to time. Under the influence of this field, the embankment together with the earth move non-uniformly in such a manner that their original velocity in the backward direction is continuously reduced.”
― Albert Einstein, Relativity

“Let us imagine ourselves transferred to our old friend, the railway carriage, which is travelling at a uniform rate. As long as it is moving uniformly, the occupant of the carriage is not sensible of its motion, and it is for this reason that he can without reluctance interpret the facts of the case as indicating that the carriage is at rest, but the embankment in motion. Moreover, according to the special principle of relativity, this interpretation is quite justified also from a physical point of view.”
― Albert Einstein, Relativity

“In gravitational fields there are no such thing as rigid bodies with Euclidean properties; thus the fictitious rigid body of reference is of no avail in the general theory of relativity. ...
For this reason non-rigid reference-bodies are used, which are, as a whole, not only moving in any way whatsoever, but which also suffer alterations in form ad lib. during their motion...
This non-rigid reference-body, ... might appropriately be termed a "reference mollusc,"...”
― Albert Einstein, Relativity: The Special and General Theory

“An observer who is sitting eccentrically on the disc K' is sensible of a force which acts outwards in a radial direction, and which would be interpreted as an effect of inertia (centrifugal force) by an observer who was at rest with respect to the original reference-body K. But the observer on the disc may regard his disc as a reference body which is “at restâ€�; on the basis of the general principle of relativity he is justified in doing this. The force acting on himself, and in fact on all other bodies which are at rest relative to the disc, he regards as the effect of a gravitational field.”
― Albert Einstein, Relativity: The Special and General Theory w/Figures & Formulas

“The purpose of mechanics is to describe how bodies change their position in space with ‘timeâ€�.”
― Albert Einstein, Relativity: The Special and the General Theory

“We thus obtain the following result: every description of events in space involves the use of a rigid body to which such events have to be referred. The resulting relationship takes for granted that the laws of Euclidean geometry hold for ‘distancesâ€�, the ‘distanceâ€� being represented physically by means of the convention of two marks on a rigid body.”
― Albert Einstein, Relativity: The Special and the General Theory

“In gravitational fields there are no such things as rigid bodies with Euclidean properties; thus the fictitious rigid body of reference is of no avail in general relativity.”
― Albert Einstein, Relativity: The Special and the General Theory

“You can only ride a bicycle ,if you are on top.”
― Einstein, The Evolution of Physics: From Early Concepts to Relativity and Quanta