explainer · general · evergreen
The Speed of Light is NOT About Light
PBS Space Time · Oct 7, 2015 · 12m 46s
What this video covers
PBS Space Time argues that the speed of light is better understood as the speed of causality, the universal limit on how fast cause and effect propagate. Light travels at that speed because it is massless, but the limit itself is a property of spacetime.
Why it surfaced in Hacker News
HN commenters send people to it whenever a thread confuses the speed of light with a light-specific limit, and several say it deepened their understanding of relativity.
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- distinct recommenders
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- recommendation months
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- strong recommendations
Recommendation context
Short excerpts from positive mentions. Open the source to read the full Hacker News discussion.
“The video about “the speed of causality” is the one that caused me to level up”
“it is a great thing to watch when you've got a short wait for something”
“These PBS Spacetime episodes should help”