Why are lightyears used to measure distance in the universe when time is not constant?

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Why are lightyears used to measure distance in the universe when time is not constant?

Post by deleted-301813 »

I was watching interstellar and had this thought. I based it on the theory that time is not constant due to its relationship to gravity.
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Re: Why are lightyears used to measure distance in the universe when time is not constant?

Post by SciB »

Hi,

Are you referring to the postulate that as an object's velocity approaches the speed of light, it's time reference slows down relative to an object going slower? I think it is called time dilation, right? I freely admit that i don't understand spacetime--but wish i could. In physics i was taught that light could be treated mathematically as a particle although as far as i know it has a mass of zero. If a photon DID have mass, one would expect the time frame for the light ray to be altered by the time dilation phenomenon, right?

You should post this query on the physics forum since those experts are more likely than us to be able to explain this apparent anomaly. I am curious to know the answer to your question. I wonder if there's a science project we could propose to test this.

Good luck!

Sybee
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