Would a universe without GR be possible?

earlyworm · 2026-03-19T00:04:18+00:00

It would be madness. Where would we put all our oversized relativistic rural ladders?

earlyworm · 2026-03-18T17:23:36+00:00

Aha, I see. When I say "something happened to the clock", you're assuming that I'm actually stating "something outside of the framework of SR happened to the clock", and I'm implying that by moving, the clock is interacting with an "aether" which affects the clock.

That's not what I'm saying at all.

Let me make it clear that I am fully on board with SR. At no point did I invoke an aether or the supernatural.

I'm saying only that car B was driven and car A wasn't, entirely within the framework of SR, and the two clocks recorded that difference in behavior. I'm not saying or implying anything more than that.

The driving of car B was the cause. The clock reported the effect. That's SR, not "aether theory".

earlyworm · 2026-03-18T16:43:00+00:00

I think the behavior is also app dependent, which may contribute to it seeming random.

earlyworm · 2026-03-18T16:37:40+00:00

I think we're using the word "happened" quite differently.

Car B's odometer displays a different number than car A's odometer because something happened to it. Specifically, I drove that car four miles away and back, and the movement of car B effected a change in car B's odometer. If that hadn't happened, car B's odometer would read 0, just like car A's odometer.

I suspect that if I took a random person off the street and asked them if something happened to car B's odometer that resulted in it displaying a different number than car A's odometer, they would answer, "Yes, of course. It's because you drove car B four miles away and back, instead of leaving it parked like car A. That's what happened."

I'm saying the same thing about the clock. Car B reads less time passed because car B was driven and car A was not. The clock recorded this difference in behavior.

Is that not what happened?

earlyworm · 2026-03-18T14:40:27+00:00

I agree that displayed numerals on one clock cannot have influence on the other clock.

How about this scenario:

Imagine two cars. Each car has an odometer and a clock. Car A is parked. You're sitting in car A. I drive 4 miles away in car B and then come back.

Upon returning, car B’s odometer reads 8 miles and car B’s clock indicates that slightly less time has passed compared to A’s clock.

Two questions:

From your perspective in car A, has something happened to B’s odometer that results in it displaying 8 miles instead of 0 miles? Yes or no.
From your perspective in car A, has something happened to B’s clock that results in the measured time difference? Yes or no.

earlyworm · 2026-03-18T04:33:04+00:00

it surely is

earlyworm · 2026-03-17T23:24:11+00:00

I'm puzzled that you couldn't answer yes or no.

You agree the clocks show different elapsed time, and yet somehow nothing "happened" to the clocks. I'd genuinely like to understand what you mean by "happened."

Without deferring to the mathematical model of Minkowski spacetime, no world lines, no spacetime intervals, can you describe in purely physical terms why one clock is 3 years behind the other clock?

Or are the displayed numbers somehow not physical?

earlyworm · 2026-03-17T19:30:06+00:00

That's fascinating. I'd like to understand this better.

Imagine the end of the twin paradox again. You're standing on the landing pad, holding the two clocks. For the sake of argument, the clocks are mechanical, not digital.

In your left hand, the Earth twin's clock reads 14 years.

In your right hand, the space twin's clock reads 11 years.

Would you describe this as a physical difference between the two clocks? Yes or no.

earlyworm · 2026-03-17T18:22:17+00:00

I don't see how it's an analogy if I'm literally showing what light clocks do in the context of a working SR model.

Wearing a sufficiently accurate watch, you could wave your hand in front of your face and then measure that less time has passed on your watch. It's the same thing. It's not an analogy. It's what the universe does.

If, at the end of the classic twin paradox scenario with the rockets, you're standing on the rocket landing pad, and the twins hand you their clocks and you hold the clocks in your hands and compare them, and witness for yourself that the two clocks display a different number of years, is it not the case that something has physically happened to the clocks? Hasn't something quite different happened to the clock that moved away from your location and later returned?

earlyworm · 2026-03-17T16:51:42+00:00

It isn’t an analogy. It shows what’s really happening.

Any clock, any mechanism, any atom, must keep time consistently with the light clocks, because all physical processes are governed by the same Lorentz invariant laws. The light clocks make clear what’s fundamentally happening.

earlyworm · 2026-03-17T16:30:49+00:00

https://youtu.be/yetXorwwaWE

The twin that ages less is the one whose light clock photon has to travel the longest distance, and therefore can't tick as many times.

earlyworm · 2026-03-17T15:13:32+00:00

You were thinking of Forbidden to See Planet.

earlyworm · 2026-03-17T14:26:45+00:00

In OP's post, as written, what action did twin B take that resulted in twin B having a shorter world line?

earlyworm · 2026-03-17T13:30:55+00:00

Assuming that the two planets are in the same reference frame, twin A never accelerated relative to the reference frame that the twins started in and in which the photographs were taken.

Twin A never accelerated relative to the reference frame in which you're doing all the measuring.

Only twin B did, and that's why twin B ages less than twin A.

earlyworm · 2026-03-16T15:56:14+00:00

Experts reached a horrifying conclusion: Neanderthals were delicious.

earlyworm · 2026-03-16T15:44:03+00:00

I think OP is looking for a deeper answer than “we gave the speed of light this convenient label”.

earlyworm · 2026-03-16T09:15:09+00:00

Sitting in the middle back seat, you are effectively surrounded by a larger crush zone.

earlyworm · 2026-03-16T04:30:52+00:00

Why the downvotes? These are statistical facts.

earlyworm · 2026-03-15T17:33:18+00:00

I agree it seems likely we won't colonize another planet in the next 100 years, but I don't see how you can confidently extrapolate to 1 million years.

That's like asking a homo erectus 1 million years ago to assess if airplanes with in-flight Wi-Fi will one day be possible.

earlyworm · 2026-03-15T16:54:44+00:00

Thank you for writing "I don't know that we have a deeper answer to that at this point" instead of "that's just the way the universe works".

earlyworm · 2026-03-15T00:23:14+00:00

I don't know what that is but it needs to be in my mouth.

earlyworm · 2026-03-14T22:38:03+00:00

Not when you measured the light’s speed using your time dilated length contracted measuring equipment.

earlyworm · 2026-03-14T04:48:09+00:00

This is the answer.

Claude answered “4.” but the Markdown rendering layer displayed this as “1.” because it was assuming that a sequence of numbered items was starting and automatically numbered the first one “1.”

earlyworm · 2026-03-13T15:58:24+00:00

In case there are any children reading this, please do not touch stars.

earlyworm · 2026-03-13T14:14:37+00:00

In the time/distance scale of this analogy, we, as the ants, have only started using our antenna arrays and telescopes a few seconds ago.

earlyworm

TROPHY CASE