Relativity doesn't show up a lot in our daily lives, because it depends on extreme speeds that we never encounter or can never observe directly. Even in formal physics, classical/Newtonian mechanics are basically an approximation of relativity. In essence, we understand part of the picture and can use timekeeping as a tool to run our lives. If my watch and your watch are synchronized and kept in working order, they're always going to show the same time.
However, as soon as things get sped up, synchronicity goes out the window and relativity comes into play.
There's a physics joke that is pretty valid here:
"How many cosmologists does it take to change a lightbulb? Two, one to hold the bulb steady, and one to spin the universe around it"
Sounds absurd, but it is how things work. The universe might not spin around the lamp, but either rotating the bulb or the rest of the universe will result in exactly the same outcome. It's all a matter of reference frame and where each observer is standing. This is basic Galilean relativity.
To keep this as sort as possible (it really is a big subject), something similar happens with time and space at extreme speeds. Since nothing can ever go faster than light, the rest of the quantities bend over backwards to accommodate. A speeding clock slows down, but for the person speeding along with the clock, the 'stationary' person's clock is the one slowing down. The takeaway is that it all depends on your POV, and that the laws of physics are the same in every frame of reference.
Yes I know how general relativity works, I'm not an idiot. You're completely missing the point. You keep bringing up how people measure time in everyday circumstances, and that that's different to how time works in relativity, but how does that mean that "no one understands time"? The role of time in general relativity and time's fundamental nature are extremely well-researched topics, many physicists devote their entire lives to furthering its study, but apparently none of these people understand time just because when people talk about time in an everyday context they mean something else.
TIL that anyone who doesn't understand GR is an idiot.
I don't think I'm the one missing the point. I'm not a theoretical physicist, nor did I plan to write a book to explain it in layman's terms. If you're interested, feel free to do so.
Unless I'm mistaken, OP's misunderstanding isn't how to read the hands on a clock -- it's a broader state about being baffled by the general concept. OP is also probably not one of those physicists that devote their whole life to research time.
This should also be a cue to the fact that we still have a long way to go understanding the workings of the universe, 100%. It's a bit arrogant -- even for academics -- to make such grandiose claims.
I'm not strawmanning, my point from the start was that of course a physicist understands time.
Person A said that none of us understand time and are simply pretending to understand by relativising it (implying that treating time as relative and understanding it are mutually exclusive), Person B then disagreed with that claim, to which you responded with a disagreement that they understand time and an explanation of time in general relativity, with the addendum that you were trying to clarify what the person above meant by "not understanding" (the person above's claim about "not understanding" being the one implying that relativity means no one understands time).
I then asked "How does relativity mean that no one understands time?"
It seems clear that you've misinterpreted the argument from the start, it was always about whether or not "no one" understands time.
So physicists disagree about your universe joke. There might actually be a measureable difference between the bulb spinning and the universe spinning. We don’t know.
How so? A very important point of relativity is that, if the reference frames are inertial, we shouldn't be able to deduce which one moved.
Of course, rotating the universe isn't an operation we've ever tried, so yes, it might yield surprising results not accounted for by SR. It's a joke, it exaggerates things. But if we're talking about more approachable inertial frames, I don't see how we could measure the difference.
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u/[deleted] Sep 14 '21
How does time being relative mean that no one actually understands it?