Relativity posts
Max Jammer’s book Concepts of Simultaneity (Johns Hopkins UP, 2006) describes the significance, meaning, and history of simultaneity in physics. Here are a few excerpts from his Introduction: … Einstein himself once admitted: “By means of a revision of the concept of simultaneity in a shapable form I arrived at the special relativity theory.” p.3 […]
This relates to the post here. There are three dimensions of motion with two measures of the extent of motion, which makes a total of six metric dimensions of motion. But these six metric dimensions collapse into two structures of one and three dimensions as the conversion factor approaches infinity. With the pace of light,
Is color an absorption phenomena or an emission phenomena? The answer is that it’s both. But absorption works subtractively whereas emission works additively. The question then is whether color is subtractive or additive. Again the answer is that it’s both. Color is a duality. Does an artist work with subtractive colors or additive colors? Here
Einstein stated his second postulate as (see here): light is propagated in vacant space, with a velocity c which is independent of the nature of motion of the emitting body. Since the one-way speed of light cannot be measured, but only the round-trip (or two-way) speed, let us adopt Winnie’s Round-Trip Light Principle as a
Galilean relativity requires the speed of light to be infinite (i.e., zero pace). Because the one-way speed of light is not known, it may be infinite as long as the two-way speed of light is finite. Such a situation is possible if light is conceived as in half-duplex telecommunications: one direction at a time is
From Galileo’s Dialogue Concerning the Two Chief World Systems, translated by Stillman Drake (UC Press, 1967): Salv. Now imagine yourself in a boat with your eyes fixed on point of the sail yard. Do you think that because the boat is moving along briskly, you will have to move your eyes in order to keep
The Principle of Relativity states that the laws of physics are the same in all inertial frames of reference (IRF). Since a frame of reference includes an orientation, that is, a convention as to which rectilinear semi-axes are positive (and so which are negative), and since there is no preferred frame of reference, each frame
This is a follow-on to posts here and here. It is common to derive the Lorentz transformation assuming velocity reciprocity, which seems to say that if a body at rest in frame of reference S´ is observed from a frame of reference S that travels with relative velocity +v, then a body at rest in
Galilean relativity is a relational theory of motion as a function of time, which leads to the Galilean transformation. Here is a defense of Galilean relativity from two postulates: (1) The Galilean principle of relativity, which states that the laws of mechanics are invariant under a Galilean transformation. (2) A convention that rectilinear coordinates for
Velocity reciprocity in relativity theory is the relation between two observers, each associated with a frame of reference and moving at different, but constant, velocities. That is, an observer-frame S observes another observer-frame S´ traveling with velocity +v relative to observer-frame S. A velocity reciprocity relation concerns the velocity of S that is observed by
