Mach's principle, GR and the nature of space

Thread starter epovo
Start date Jun 16, 2013
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Gr Nature Principle Space

In summary, Mach's principle came from the notion that empty space is nothingness. This is not the prevalent idea now. Space seems to be a bubbly thing after all, and filled with the Higgs field. Is this the thing against which rotation happens? What is the current thinking about this?

Jun 18, 2013

WannabeNewton

Science Advisor

Nabeshin said:

Do you know how this relates to the calculation of the Chern-Pontryagin invariant? I was given the impression the CP invariant also tells you about the 'spin' in a spacetime (region). However, I don't entirely understand it outside the trivial case of kerr, and know it (oddly enough) produces zero for the godel universe.

The only thing I know about the CP invariant is that it is related to the winding number of an instanton. The rest is beyond me however, sorry to say

You might try ch22 of Frankel's "Geometry of Physics".

<h2>1. What is Mach's principle?</h2><p>Mach's principle is a concept in physics that suggests the inertia (resistance to change in motion) of an object is determined by the distribution of all other matter in the universe. This means that the motion of an object is not solely determined by its own mass, but also by the mass and distribution of all other objects in the universe.</p><h2>2. How does Mach's principle relate to the theory of general relativity?</h2><p>Albert Einstein's theory of general relativity is based on the principle of equivalence, which states that the effects of gravity are indistinguishable from the effects of acceleration. Mach's principle is incorporated into general relativity through the idea that the distribution of matter in the universe affects the curvature of spacetime, which in turn determines the motion of objects.</p><h2>3. What is the nature of space according to general relativity?</h2><p>General relativity describes space as a dynamic, four-dimensional entity known as spacetime. According to this theory, the presence of matter and energy in the universe causes spacetime to curve, resulting in the effects of gravity.</p><h2>4. How does general relativity explain the behavior of objects in space?</h2><p>General relativity explains the behavior of objects in space through the concept of geodesics, which are the shortest paths between two points in curved spacetime. Objects follow these geodesics, which are determined by the curvature of spacetime, resulting in the observed effects of gravity.</p><h2>5. Can Mach's principle and general relativity be tested?</h2><p>There have been attempts to test Mach's principle and general relativity through various experiments and observations, such as the Pound-Rebka experiment and the detection of gravitational waves. However, the nature of these concepts makes it difficult to definitively prove or disprove them. Further research and advancements in technology may provide more insight into these theories.</p>

1. What is Mach's principle?

Mach's principle is a concept in physics that suggests the inertia (resistance to change in motion) of an object is determined by the distribution of all other matter in the universe. This means that the motion of an object is not solely determined by its own mass, but also by the mass and distribution of all other objects in the universe.

2. How does Mach's principle relate to the theory of general relativity?

Albert Einstein's theory of general relativity is based on the principle of equivalence, which states that the effects of gravity are indistinguishable from the effects of acceleration. Mach's principle is incorporated into general relativity through the idea that the distribution of matter in the universe affects the curvature of spacetime, which in turn determines the motion of objects.

3. What is the nature of space according to general relativity?

General relativity describes space as a dynamic, four-dimensional entity known as spacetime. According to this theory, the presence of matter and energy in the universe causes spacetime to curve, resulting in the effects of gravity.

4. How does general relativity explain the behavior of objects in space?

General relativity explains the behavior of objects in space through the concept of geodesics, which are the shortest paths between two points in curved spacetime. Objects follow these geodesics, which are determined by the curvature of spacetime, resulting in the observed effects of gravity.

5. Can Mach's principle and general relativity be tested?

There have been attempts to test Mach's principle and general relativity through various experiments and observations, such as the Pound-Rebka experiment and the detection of gravitational waves. However, the nature of these concepts makes it difficult to definitively prove or disprove them. Further research and advancements in technology may provide more insight into these theories.