Questions tagged [relativity-theory]

For questions regarding either the special or general theories of relativity.

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Who first discussed the Lorentz force with respect to special relativity?

The fact that a Lorentz force in a reference frame 1 can become a Coulomb force in another reference frame 2 has always astonished me, especially because the velocities involved are really small. I ...
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478 views

How did Einstein know tensors would be needed in the EFEs?

I'd really never studied tensors until I started studying the Einstein Field Equations. Since then, I have realized they are fairly common tool in physics and pretty basic to understanding many areas. ...
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188 views

Did Einstein ever refer to the coordinate speed/velocity of light?

In modern parlance we talk about two different speeds of light in general relativity. We distinguish between the local speed of light, which is always $c$, and the coordinate speed of light, which can ...
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208 views

First paper introducing the concept of four-vectors

I'm trying to find the first paper in which the concept of four-vectors was introduced. I read "Principle of Relativity" by H. Minkowski but he only presents the notion of metric and invariant space-...
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46 views

First discussion of radial/volume excess in General Relativity

A well-known (but usually only cursorily discussed) feature of General Relativity is the so-called radial (or volume) excess due to the curvature of spacetime in the presence of mass/energy (or more ...
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82 views

What was Einstein's reasoning to conclude particles follows geodesics through spacetime?

When formulating General Relatvity Einstein proposed that freely falling particles, that is those subject to no forces other than gravity, follows geodesics through spacetime. In other words, those ...
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66 views

Historical interpretation of symmetries required by Principle of Relativity

Einstein's 1905 paper discussed electromagnetism and the laws of mechanics. But did not discuss gravity, and of course did not discuss the strong or weak nuclear forces. Principle of Relativity - (...
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1answer
128 views

What is a spacetime continuum?

A very common expression I see in pop science is "the spacetime continuum". This expression isn't commonly used in modern discussions of general relativity, but looking at some older papers on the ...
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59 views

Who first noticed that the radiation pressure formula $p=U/c$ agreed with $E=pc$ from special relativity?

Does anyone know behind stories? As it seems that $p=U/c$ was known before the advent of special theory of relativity, (Halliday, Resnick, Walker says that Maxwell derived this.) when $E=pc$ was first ...
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93 views

Modification of Newtonian Gravity based on Maxwell's Theory

As is well-known, Maxwell's equations were already consistent with Special Theory of Relativity while the Newtonian law of Gravitation wasn't. It can be shown by solving the equations of Maxwell for a ...
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93 views

First appearance of the timelike cylinder spacetime

Spacetimes with causality violations go back a bit of a way (at least as far back as Herman Weyl's "Space, Time and Matter" in 1922, followed by the Gödel spacetime in 1949), but one of the simplest ...
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1answer
58 views

Was the pre-special relativity discussion a hot topic in the late nineteenth and early twentieth century?

We know that low-dimensional materials and topological materials are some of the current hot topics in Physics. Did this happen with the pre-special relativity discussions in the late nineteenth and ...
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Were Christoffel symbols used by Riemann?

The answer to the question would appear to be "no" looking at the transcription of Riemann's 1854 Ueber die Hypothesen, welche der Geometrie zu Grunde liegen lecture. However, Bernhard Riemann (1826-...
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132 views

Was Einstein original formula E =1/2 m c^2?

I read somewhere that, but unfortunately I cannot retrace where, can you help me find a reliable source? Actually, they said a sad story, hardly believable: They stated that Einstein had circulated a ...