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I thought when a theory carries paradoxes, and they go unresolved, eventually they get called inconsistencies and the theory is assumed wrong somewhere.

GR doesn't work at distances, say between adjacent galaxies. The answer I got about that was that at such distances what does it mean to talk about the velocity of Andromeda.

The reason that's unconvincing is while it's obviously true in objective reality, A set of abstract theory and equation don't have to worry about practical realities...they work with simplified scenarios, and if they fall down, then normally we say the theory is wrong. Not absolutely wrong...no one ever means that. But wrong...or Right let's say, within limiting bounds.

I didn't say that at the time, but what was said to me was that GR is a LOCAL theory only. I don't think that true in the sense of a formal position. And this matters because if GR is wrong outside a certain bounds, then by informally saying it's always been a local theory, what we're really doing is avoiding the issue.

But let's say it is a local theory, and this is the context of my question.

If GR is a local theory, why is being used in other contexts as a primary source for large scale observables and knock-on cosmology theory out to the very edge AND BEYOND the visible universe?

And that's not the only 'edge' GR gets extended. The implied properties of Spacetime, now results in serious scientists apparently, arguing for BlockTime as a candidate for inclusion in our most precious and hard won incumbent knowledge. l

And actually the space time relatedness between points is very similar to what is being asked in that Andromeda paradox. This seems so wrong.

Sorry had to take back the total surrender :)

I think it's a reasonable question (not the one above) why paradoxes in GR are treated differently. The Andromeda Paradox, no matter what purpose its invention was to serve, demonstrates a result of the tools, that wouldn't happen.

Why is it preferable to entertain something like blocktime that totally dehumanizes us, but not see fit to entertain that a paradox has a traditional context in science of signalling a problems in theory

Lucy Meadow
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You are misunderstanding the word local in this context. GR deals with long distance gravitation just fine, even between here and Andromeda. Local means that at a given time the gravitational response of an object (like the Milky Way) just depends on the fields that are around it, and that the fields only depend on the fields nearby a little earlier and the nearby masses. In other words, the theory expresses everything in space and time differential equations. GR gives us the way to calculate those fields and how they evolve in time. The only known problem with GR is at very short distances and very high energy densities where quantum effects come into play.

The Maxwell equations are local by the same definition. They also work fine for predicting the light we see from Andromeda. Newton's gravity is not local. It would say that the Milky Way would react gravitationally to where Andromeda is now, not 2.5Myr ago.

Ross Millikan
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Let me give a simple example from computer graphics:

Suppose I am given the task to fit a three dimensional shape, lets say a mountain, so that I can then plot it any way I want in three dimensions. I would take a set of mathematical complete functions, as an example take the Fourier series because the mountain has many ups and downs, and will fit with the expansion up to as many terms as necessary to give me a good three dimensional resolution form of the mountain.

There will be many components of sines and cosines adding up to my final fit.

Does this mean that the mountain is composed by different bits of sines and cosines added up?

General Relativity gives us a complete set of functions to describe our observable universe and has been validated where ever it has been tested, i.e. it predicts and it fits known observations. It is a very successful physics theory , locality and all : no action at a distance, all interactions happen at (x,y,z,t) four dimensional points.

It is a successful theory and can be used to evaluate unobservable situations in the same way that there will be coefficients for all the fourier transform terms in the model above, but it makes little sense to tie up oneself in a knot about unphysical "predictions" in GR, i.e, that no experiment can be made and no observations of it. Physicists tend to trust the predictions because the parts that can be tested work. The rest is mathematics.

anna v
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