> This is the consequence of all the forces of physics being gauge invariant: absolute values don't exist—only differences matter
there's something about this quote that i really like, going to have to use it out of context on people
there's something about this quote that i really like, going to have to use it out of context on people
From images: information _is _ the differences between pixels
From opinions: my opinion alone is worthless, but a difference of opinions? now we've got something
From relationships, graphs, networks: edges are _differences_ between nodes. the edges are everything. nodes alone... are meaningless
From music: this one is a little easier to take at face value, you can't have a sound without a change (difference) over time. the speaker cone can only wobble...
Not sure about the absoluteness or correctness of this intuition, please criticize
Any time an absolute reference point is assumed, all downstream calculations are effectively absolutes
You can also ask a UI designer about "absolute" colors. One color needs to be different depending on the context it's in order to LOOK the same (it's size/thickness, background, what it's next to).
If OP had said “perceived color”, I would agree. But we’re talking at pixel level here.
Suppose you have a reference pixel but don’t know its value. You don’t get the color right but there is plenty of other information there, right? Which pixel also probably limits the range of values since your highest and lowest values are probably within a certain range.
Heck, even differences are usually non-physical; it's their ratio that matters. I.e. choosing feet or meters doesn't change the physics; the same goes for energy. So we have two free parameters: choice of origin and choice of units.
Baez only hints at this near the end of the above article, but we can actually fuse translations and scalings into a single group of elements that are combined translation + scale operations, an affine group. It turns out that this combined group is just a certain combination (semidirect product[0]) of the translation and scaling groups, as one would hope.
And once we are thinking about affine groups, it's natural to consider more complicated ones. Most famous is probably the Poincaré group[1]. That is, points in space are physically described by G-torsors over the Poincaré group!
Although - I had it explained to me that the fabric of space was entering a black hole faster than light could travel, which is why light couldn't escape.
Which made me wonder - is light (the massless object) travelling, or is it space travelling and carrying things at different velocities.
Wut. No there's not? Specifically for spacetime it's obvious to see that's not correct because the time axis has no upper bound.
Now, given that in quadrillions of quadrillions of years all black holes will evaporate and potentially even protons decay there could be a time in the universe where everything is mass less radiation.