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Time is a dimension, but not like space

(bigthink.com)
171 points belter | 1 comments | 17 Oct 24 15:29 UTC | HN request time: 0s | source
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heed ◴[20 Oct 24 05:48 UTC] No.41893173[source]▶
Also consider the speed of light is also the speed of causality. If there was no such limit it means it would be possible for effects to precede causes which would lead to a very different kind of universe!
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MattPalmer1086 ◴[20 Oct 24 09:18 UTC] No.41894129[source]▶
How could an effect precede a cause if there were no speed limit to causality?

No matter how fast an effect propogates, it is always after the cause (with an infinite speed, I guess effects happen instantaneously, but not before).

Of course, this doesn't fit with a universe described by general relativity, where time can be different for different observers. But you wouldn't have a universe described by general relativity without that constraint in the first place.

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andsoitis ◴[20 Oct 24 14:30 UTC] No.41895599[source]▶
> How could an effect precede a cause if there were no speed limit to causality?

> No matter how fast an effect propogates, it is always after the cause (with an infinite speed, I guess effects happen instantaneously, but not before).

If everything happens instantaneously then there is no real cause and effect, and the universe would be over before it really got started.

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amelius ◴[20 Oct 24 14:48 UTC] No.41895699[source]▶
No speed limit does not mean that everything goes infinitely fast.
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lazide ◴[20 Oct 24 14:56 UTC] No.41895745[source]▶
If the speed limit is infinite, what else would you expect to happen?
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1. jncfhnb ◴[21 Oct 24 11:51 UTC] No.41903128{3}[source]▶
The speed limit being infinitely large does not intuitively imply that anything should be able to go at infinite speed.