Eli5: How can light not experience the passage of time if it travels at 670 million MPH – a measurement of time (and space)

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If light travels at 670 million miles per hour, then that means in one hour it will travel 670 million miles. At 2 hours it will travel 1214 million miles etc. This to me sounds like a measurement of time, just on such a huge scale that we can’t comprehend it. But in the grand scheme of the cosmos this is not that crazy of a scale. I would think it’s just saying light doesn’t experience time *relative* to us. But Einstein says no- no matter what, light’s speed doesn’t change and, what, relativity just doesn’t matter? It feels like a paradox

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Anonymous 0 Comments

First off, it’s impossible for anything with mass to reach the speed of light. But let’s allow it for this hypothetical.

Think of it like this, from your own perspective, there is no limit on how fast you can go. There is a speed so fast that you will reach your destination instantaneously, no matter how far it is. That’s what it’s like for light and why it experiences no time lapse while traveling. But because of special relativity, any outside observer would see you traveling at the fixed speed of light. Even an observer going 95% the speed of light would see you going the full speed of light relative to them, because the speed of light is a constant no matter how fast the observer is going, and that is all made possible because of time dilation.

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