From Minute Physics.
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This video is about how Russian physicist Aleksandr Fridman corrected Albert Einstein about the expansion of the universe. Einstein thought that general relativity implied that space had to be static and unchanging, but he had made a technical error regarding the differentiation of the metric (in particular, I believe he mistook the determinant of the metric for a scalar rather than a tensor density of weight 2). Friedmann didn’t make this differential geometric mistake, and the cosmologies he found from the Einstein Equations were more varied in their properties – they could be expanding, or contracting, or (with the cosmological constant), static.
Einstein Wrongly Criticizes Alexander Friedmann
Alexander Friedmann Corrects Einstein
Einstein Admits his Mathematical Mistake
Interrogating the Legend of Einstein’s “Biggest Blunder”
Cosmological Considerations in the General Theory of Relativity
On the General Theory of Relativity (Einstein)
The Field Equations of Gravitation
The Einstein Field Equations
Presentation about the Sequence of Events
Minute Physics provides an energetic and entertaining view of old and new problems in physics — all in a minute!
Created by Henry Reich