Could the values of the physical constants (the speed of light, for example) been anything different than what they are?
Or do they exist a priori, and the value of a physical constant couldn’t differ any more than a shape with 3 sides can be a square?
Perhaps the underlying mechanics that determine the physical constants are intertwined with all other properties of the basic fundamental structure of existence, such as geometry (there is up, down, left, right, forwards, backwards, and presumably nothing else besides a combination of those) and mathematics. Perhaps there is only one physical constant that exists independently (probably the speed of light) which all other physical constants are derived from, therefore all physical constants are variables defined by one another in an interconnected virtual formula.
For example, perhaps the speed of light has to be 299,792,458 meters/second because what is perceived as “distance” by us is fundamentally based off of the speed of light, and the size of the matter that makes us up was also determined by the speed of light – so hypothetically, if a universe existed where the speed of light was 600,000 meters/second (by our measurements) instead of 299,792,458, the matter in that hypothetical universe would be twice as large as a result, and all other physical constants would be twice what they are in our model of physics; but to the inhabitants of that hypothetical universe, we would appear to be 1/2 their size, and our matter and particles would be 1/2 as large.
Although if all physical constants are interconnected, then such a hypothetical universe would likely be impossible to exist.
My understanding is that there are a fairly narrow set of physical constants that would actually make a stable universe – or at least a universe that is stable given what we know. There was a nifty graph somewhere that provided a nice pithy explanation but my google-fu is weak right now.
Yes. And they aren’t constant even now. Take a look at this report on a super-accurate optical clock. It’s so precise that you can see two of these clocks losing synchronisation when they’re separated by only a foot of vertical elevation. Now take a look at wiki re time dilation, and note the bit that says consider a simple clock consisting of two mirrors A and B, between which a light pulse is bouncing. When you simplify the optical clocks to parallel-mirror light clocks, when they lose synchronisation this is what’s happening:
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The light’s going slower at the lower elevation.
No.
Pretty much. The best place to see this “intertwining” is in the fine-structure constant alpha, wherein α = e² / 4πε[size=85]o[/size]ħc. It’s a running constant. Which means it isn’t constant. See NIST for more on this. The important bit is “Thus α depends upon the energy at which it is measured, increasing with increasing energy, and is considered an effective or running coupling constant”. But note that the article talks about screening and alpha varying because e varies, e being “effective charge”. That rather muddies the water, in that something like an electron has unit charge. The effect of this varies, because the environment it’s in varies. You’ll probably be aware that c = √(1/ε[size=85]o[/size]μ[size=85]o[/size]). So imagine you’ve got a unit-charge electron in front of you, and you can measure the effect of that charge increasing and reducing. Where are you? You’re in an elevator.
Geometry does come into it, but 4π is still 4π. There’s nothing fancy or mysterious going on.
I’d say they’re all interconnected, but that vacuum impedance Z[size=85]o[/size] = √(μ[size=85]o[/size]/ε[size=85]o[/size]) is most important.
Pretty much. Suppose I could snap by fingers and double the speed of light at a stroke. You wouldn’t be able to tell the difference.
Light moves at the speed that it does. We use the motion of light to define the second and thence the metre. Then we use them to measure the speed of light. That’s why the locally-measured speed of light is always the same. You might measure the speed of light to be 299,792,458 m/s, and so might I. At different elevations our metres are the same because slower light and bigger seconds cancel each other out. But our seconds are still different, so those two speeds are different too.
Look at the links in my post, the most important one refers to a NIST web page which includes this:
Thus α depends upon the energy at which it is measured, increasing with increasing energy, and is considered an effective or running coupling constant..
A running constant isn’t constant. Most people just don’t know about running constants, and instead they get fed the multiverse woo about other universes where the “fundamental constants” are different. It’s garbage. They don’t know about Einstein’s variable speed of light either. Here’s something I’ve written previously:
I’m not kidding you about this, Peachy. Do some research. But most importantly think about those optical clocks. Clocks don’t actually measure “the flow of time”. They clock up some kind of motion, usually a regular motion, and give you a tally that you call the time. It doesn’t matter whether it’s a pendulum clock, a quartz wristwatch, or an atomic clock. If the clock’s going slower, the motion’s going slower, and that’s it.
With respect to Farsight’s post I agree in principal.
However, he quotes Einstein, always a dangerous thing to do, and worse yet Einstein’s equation is wrong for multiple reasons in this particular case.
The particular quote:
“Einstein wrote:If we call the velocity of light at the origin of co-ordinates co, then the velocity of light c at a place with the gravitation potential Φ will be given by the relation c = co(1 + Φ/c²)”.
If you have a winning argument, it is best not to support it with faulty data.
If you want to know why Einstein is wrong on this equation you can read:
That’s the data. There’s no “time flowing slower” to be seen, just light moving through space. Einstein didn’t get everything right, but he was right that the speed of light varies with gravitational potential. This has been rather swept under the carpet in what might be called “the modern interpretation of general relativity”. See arxiv.org/abs/physics/0204044 for an essay on the difference between it and “the Einstein interpretation”.
A pleasure Ed. There’s some odd stuff going on in physics, but you don’t always realise it. I was pretty shocked when I read some original material, and found out that what I’d been taught wasn’t at all like like what was actually said by the likes of Maxwell and Einstein.
There are many studies suggesting the possibility that universal “constants” evolve with time. I personally find this to be the most aesthetic perspective, thinking that they simply change slowly with respect to our livespans, and that our current laws of physics are perhaps “riding the tangent line” to these changes. However, the studies that suggest that the constants aren’t constant are nowhere near sufficiently compelling to be mainstream. The right thing to say about it is “possibly, but there’s no rational basis for certainty.”
Are you saying that some light moves at different speeds than other light?
the speed of light in a vacuum is the speed of light in a vacuum. Velocity is relative, therefore c (the speed of light) is a constant. Get used to it.
Mass and energy are equivalent - and a photon (light) is the only particle which has energy but has no mass (well, an infinitely small mass anyways)-- it is the smallest elementary particle that can exist, the smallest unit of “something”, which is why it moves the fastest (because it takes less energy to move something that is smaller).
Unless there are quanta of light flying around with a mass that’s different from each other (which there isn’t), then you lose.
why? you didn’t prove it. if you happen to turn out right, it’s no better than a guess. if you own a green shirt, you should find this post and give me some credit, cuz i’m guessing you have a green shirt.
I’ve a feeling that I remember vacuum energy (lambda) has a few stable values stepping down towards zero (but not actually reaching it) but a switch to another lower value would irrevocably erradicate all life in the universe as we know it.
So if we changed the value of the speed of light (say, increasing or decreasing the speed), everything else (including things as fundamental as ‘distance’ itself) would change with it, and therefore it would seem like nothing changed?
There’s a lot of scope in claiming the speed of light isn’t or hasn’t always been constant. There’s no real evidence but constants should or should I say could change over time, perhaps not just in the early universe…?
There are some constants that have to be within a range to support life, the fine structure constant for example. But there is no reason constants cannot change within a range.
Exactly true.
For all we could ever know, the speed of light for the entire universe could be universally oscillating up and down all the time.
As long as there was no phase shifting of any kind, nothing would change from our perspective.
Of course it is irrational to bother with notions that propose such variation because; “Existence rationally defined; If it has absolutely no affect, it doesn’t exist.”
Thus a rational metaphyscist declares that such oscillations simply do not exist merely because it is an irrational waste of thought to do otherwise.
That, from my perspective, is merely the view from our new age Quantum Religion.
The absolute nature of the speed of light has been privately proven (for whatever that’s worth to you guys).