Wednesday, November 3, 2021

There is a charge, i.e., mass-energy in gravitational waves: are there longitudinal waves, too?

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In electromagnetics, a wave carries a zero charge. We believe that there exist no longitudinal electromagnetic waves. But assume that the wa...

Pressure involves tidal effects in general relativity

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Assume that we have a spherically symmetric mass, and inside it springs which prevent contraction.                           ● spherical mas...
Monday, November 1, 2021

SOLVED: How to make the Einstein Ricci tensor coordinate independent - we do not need to

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We had a confusion about tensors. In the Einstein field equations, each side is a tensor. To change to a new coordinate system we have to tr...
Sunday, October 31, 2021

How to make the Einstein Ricci curvature definition coordinate independent?

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UPDATE November 1, 2021: We do not need to make Ricci curvature coordinate independent. A tensor -  by definition - is coordinate dependent!...
Saturday, October 30, 2021

Riemann and Ricci curvature as defined by Albert Einstein are coordinate dependent

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UPDATE November 1, 2021: Of course, the Ricci curvature tensor is coordinate dependent. A tensor is something that you have to transform  to...
Friday, October 29, 2021

Friedmann equations have a solution for a mix of matter - even for a sudden jump in pressure

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We presented a hypothesis in our blog post on October 20, 2021 that a mixture of slow massive matter and radiation has no solution for both ...
Monday, October 25, 2021

Friedmann equations and changing the metric of time

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UPDATE October 29, 2021: We updated the text to reflect the fact that the theorem in the October 16, 2021 blog post is erroneous. ---- Our p...