Why No One Has Measured The Speed Of Light
6 人推荐 · 跨 7 个月 · 2020–2024
中文导读
科普顶流 Veritasium 的烧脑之作：人类至今测得的其实永远只是光速的“双向往返速度”，而“单向光速”在物理上从未被真正独立测量过，因为校准时钟的过程本身就已经预设了光速不变的前提。
为什么 HN 推它
物理学讨论区里的常客与基准引用，每当探讨光速定义、爱因斯坦钟慢同步以及物理学中不可被证伪的前提假设时，大家都会推荐这篇思想实验。
「即便仅仅把它当成一个思想实验来看，我也觉得这个视频极具说服力。」HN 网友原话：I found the video very compelling even as a thought experiment.
英文原摘要（HackerTube / Claude 整理）
Veritasium explains why the one-way speed of light has never been measured, only the round-trip speed, since measuring it requires synchronized clocks that assume the answer. It explores the implications for relativity.
Used as the standard reference in threads about light speed, clock synchronization and untestable assumptions in physics.
HN 上的提及
there is no way to prove the speed of light is uniform, only that the round trip speed is 'c'.
Veritasium just had a good video which discusses this
I found the video very compelling even as a thought experiment.
There is a Veritasium video really fun to watch which exmplains with examples why you cannot measure one way speed of light
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