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Everyone knows the famous example of gravity where two weights are placed on a stretched out sheet of fabric, and the two weights come together exemplifying gravity, but does anyone know who originally came up with this idea? I think I read that it was Einstein, but with all the false info out there who knows. Anybody?
For example, this metaphor at some level assumes the fabric, that is space, is somehow anchored at its perimeter and suspended in the middle like a trampoline. Why is the fabric not lying flat on a table? If space was a fabric laying flat on a table, this gravity metaphor would not work. Or, if it was not anchored at the perimeter, but only suspended, the two masses would both fall, without attraction. Attachment or not makes or breaks it.
Extending a 2D trampoline to gravity in 3D space does not work.The extra dimension you are missing is the impact on time dilation of massive objects.That's why you have to move from trampoline analogies to Einstein's Spacetime, instead of trying to produce a better trampoline analogy.
It has no more physical reality than other abstract nouns, such as "Motion".
Quote from: charles1948 on 21/02/2021 20:58:43It has no more physical reality than other abstract nouns, such as "Motion".There is nothing abstract about motion. If your motion changes too quickly it can kill you, or at least cause serious injury. Thatís not an abstract concept.
Is "Time" an actual physical thing. Which can "dilate"?
There's no "motion". You don't change your "motion". What you do, is move from one place to another.I think you're getting confused by the artificial linguistic distinction between verbs and nouns.
For example, suppose you said: "I drink more at the weekend".And I said: "No, you mean your drinkage increases at the weekend"How would you respond? Politely!
I think I read that it was Einstein"