Light and Time

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Alex (@hollowinfinity)    2 years, 4 months ago

My question is do we simply base time measurement off of light? Is it possible to measure time at all without light and its constant speed? If so, how can we be sure of time at all? We measure our time based on light from the sun, and its not constant because of all the mediums it must pass through. Since the sun is the source of light, then do stars have no sense of duration at all?
Secondly, if distances literally converge when going the speed of light, or really fast, and we measure things based off of light, then how are we certain there is actually space at all? All distances could be converged upon itself into a point, yet there is no way for us to know because we don’t move fast enough.

3 votes, posted 04.18.2012 at 9:40 am
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Alex (@alexishungry)2 years, 3 months ago ago

@kushna According to most scientists, a period existed after the big bang that was completely dark (the dark ages), BUT… you do bring up a good point. Because Einstein’s relativity theory states that time is warped with increased speed in order to keep light’s speed constant in all relative situations, why would this still apply without light around?

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Alex (@hollowinfinity)2 years, 3 months ago ago

Isn’t it just as likely though, that the big bang happened with such tremendous force that it covered/created A LOT of space/time virtually in a blink of an eye. The entirety of the dark ages could’ve really, relatively happened instantaneously. Did the big bang need time?

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Kushna Mufeed (@kushna)2 years, 3 months ago ago

@alexishungry, I do know that the early universe was opaque and not transparent as it is now. However, that doesn’t mean that photons still couldn’t exist within it. Just that they would be emitted and absorbed quickly.

I looked up the Dark Ages and according to Wikipedia, “There is light but not light we could observe through telescopes.” https://en.wikipedia.org/wiki/Chronology_of_the_universe#Dark_ages

@hollowinfinity, If you check out the link above, you’ll see that many stages of the early universe happened in extremely short amounts of times. So while not instantaneous, the initial expansion of the universe happened in a relatively short amount of time. However, by the Dark Ages lasted quite some time, “between 150 million to 800 million years after the Big Bang.”

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Alex (@hollowinfinity)2 years, 3 months ago ago

This is what gets me though. Time/space is relative. If we lived a billion light years away, we might think the Universe is younger than we thought, and if we lived later than now, all that light would be quite far away to detect, and we might as well assume the universe is younger too (or older)
We measure duration mostly from light, so in a sense we can never be sure if our own sun uses time to its advantage. This is what confuses me about people saying, “Oh this star will supernova in a couple million years.” How do we know this, when we are confined to observation from this rock?

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John (@iamhigh)2 years, 3 months ago ago

“Oh this star will supernova in a couple million years.” How do we know this, when we are confined to observation from this rock?”

THISSS!!!!!

AND

TIME IS NOW!

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