
Are the Constants of Physics Constant? - Hooke
http://blogs.scientificamerican.com/guest-blog/are-the-constants-of-physics-constant/
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whatshisface
M(n) = floor[A^3^n]

The above will give you primes, so long as A is filled in with the right
constant. So, in a strange way, you might imagine A as number that has
information about primes written inside of it. The formula could be thought of
as a decompressor to get that information out.

In a similar way, could some of our physical constants be "hiding" structure
inside of them? If we got all of the structure out and into math, could we end
up with a constant-less physics?

~~~
gizmo686
This is essentially what you get in String Theory. The problem is that String
Theory requires you to define the "shape" of the extra dimensions. Once you do
this, all of the fundamental constants naturally follow. However, there are so
many potential shapes that are mathematically valid that this essentially
moves the problem from out universe having arbitrary constants to our universe
being an arbitrary shape.

Unfortunately, it is possible that there is literally to elegant solution to
this. For example, consider our solar system. At one point, people tried to
explain the distance of the planets from the sun without invoking arbitrary
constants. We now know that the distance between the planets and the sun are
in largly arbitrary, because we are but one of many solar systems and other
solar systems have different distances.

Similarly, it is possible (although potentially non-provable and non-
falsifiable). That we live in but one of many universes, and that other
universes have different constants. If this is true then there is no way to
avoid the fact that our universe has some arbitrary constant (even if we
obscure it by calling it an arbitrary shape).

~~~
andrewflnr
Is there a finite or countable number of these "shapes"? That would still be
better than a handful of arbitrary-precision numbers. :)

~~~
Intermernet
Currently thought to be finite, but _very_ large. Some info at
[https://en.wikipedia.org/wiki/String_theory_landscape](https://en.wikipedia.org/wiki/String_theory_landscape)
and [http://physics.stackexchange.com/questions/2873/where-
does-t...](http://physics.stackexchange.com/questions/2873/where-does-
the-10500-estimate-for-the-number-of-stringy-vacua-come-from)

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lfowles
Tangential, but I found one of my favorite books on a thread related to this
topic, so I thought I would pass on the favor. Vernor Vinge's _A Fire Upon The
Deep_ is based on the premise that physics changes throughout the galaxy. The
inner "slow" sections have physics that is normal to us, but the outer
sections allow faster than light travel and incredible AI.

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acqq
Note, now we know, the measured mass ratio is 1836.15267389 which is not 6
times pi to 5 = 1836.1181087116884.

And the measured fine structure constant alpha^{-1} also isn't just 137 but
137.035,999,139(31)

[https://en.wikipedia.org/wiki/Fine-
structure_constant](https://en.wikipedia.org/wiki/Fine-structure_constant)

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spacejoe
The Gravitational Constant could conceivably not be a constant. Experimental
measurements are over the map - most only agree on 3 - 5 significant digits of
accuracy.

~~~
greglindahl
Note this text from Wikipedia: "Under the assumption that the physics of type
Ia supernovae are universal, analysis of observations of 580 type Ia
supernovae has shown that the gravitational constant has varied by less than
one part in ten billion per year over the last nine billion years.[13]"

The ref is: J. Mould; S. A. Uddin (2014-04-10), "Constraining a Possible
Variation of G with Type Ia Supernovae", Publications of the Astronomical
Society of Australia 31: e015, arXiv:1402.1534, Bibcode:2014PASA...31...15M,
doi:10.1017/pasa.2014.9

It's not the first paper to look into that issue, either!

Always fun to remind people that physics involves more than what happens
inside the lab.

~~~
spacejoe
Yet we don't have a high precision value for it.

From the same Wikipedia article:

"Published values of G have varied rather broadly, and some recent
measurements of high precision are, in fact, mutually exclusive.[4][6]"

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castratikron
Didn't even read the article, but there's at least one "constant" that has
been increasing over time. It's called Hubble's Constant, and it's used to
determine how quickly a galaxy is moving away from us. The farther away a
galaxy is from us, the faster it moves away (Hubble's Law). Since the universe
is expanding, the speed at which galaxies move is actually increasing, which
is why the value of Hubble's constant isn't actually constant, but also
increasing.

[http://hyperphysics.phy-
astr.gsu.edu/hbase/astro/hubble.html](http://hyperphysics.phy-
astr.gsu.edu/hbase/astro/hubble.html)

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ankurdhama
These constants are invented by humans so that we can make sense of the data
collected through measurement.

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daxfohl
They may alter by, oh, .0000000001 or way less than that, say, when a galaxy
cluster explodes or something. Which even if true may be essentially
impossible to notice given Planck. So how do we know what's going on at that
level? We can't explode galaxy clusters. And maybe there are thousands of
layers even below that; you'd need gajillions of universes exploding /
collapsing to notice the trend of some sub-Planckian thing happening
statistically per universe. And maybe even thousands of layers below that.

Or maybe not.

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dschiptsov
A constant is mathematical abstraction. There is no mathematics outside
people's minds. There are no numbers outside mind of an observer, no time, no
space.

Which abstractions are good enough approximations of laws of the Universe, and
which are mere creations of the mind is an open question since the first human
language has been established.) Upanishads and the Buddha have tried to
clarify the mess a bit, but...

According to the finest human philosophy, nothing is permanent, hence, nothing
is constant. Atoms - the basic building blocks, are "stable" as long as they
has been made inside a star, but they are not permanent or constant (they
might end up in another star). Their weights, electrical properties are stable
("constant" is not applicable here, being from another domain of pure
abstractions which we call mathematics).

Mathematical ratios could be computed, of course, given that measurements are
accurate enough, but they does not exist either. These are _rarest_ concepts
of the mind which reflect some aspects of reality _as it is_.

~~~
tremon
I think the article is talking about physical properties, like c, h, or G,
that we measure to be the same every time.

You seem to be talking about numerical representations.

~~~
hansen
c and ℏ don’t encode any physics, they just fix measuring units. Actually it’s
common to choose units s.t. ℏ = c = 1.

~~~
simonh
So the same constants can have different numerical representations. Isn't that
what tremon just said?

~~~
hansen
Maybe I haven’t understood him right, but he said:

> […] physical properties, like c, h […]

which is false, c and ℏ aren’t “physical properties”. The numerical values we
attach to them are merely a convention.

In SI units c isn’t even something that is measured. The second is defined via
a measurement, c has a fixed defined value (no measurement involved), and the
meter is defined via the second and c. In natural units this is even simpler:
ℏ = c = 1.

The fine structure constant is another thing. It caries no dimension and
encodes the strength of EM coupling. But as an interesting site note: These
coupling constant are pretty complicated things, they actually depend on the
energy/length scale of your experiment. The numbers you find in text books are
just the low energy limits.

~~~
tremon
Well, I did mean the physical properties behind the symbols, i.e. speed of
light, energy quantum, gravitational constant.

I understand that the numerical quantities we assign to those constants are
arbitrary, but even though they're not dimensionless, the physical properties
they represent are still considered constant, am I right?

~~~
hansen
> the physical properties behind the symbols

Maybe my interpretation is a bit mathematical and a physicist would disagree
but I wouldn’t call the speed of light or the Planck constant a “physical
property”.

In case of the speed of light the actually geometric thing, that exists w/o
resorting to some arbitrary choice of units, is causality. In the case of the
Planck constant there are different equivalent properties that I would call
“physical”, but it all boils down to representations of symmetries.

The gravitational constant is more complicated and I’m not quite sure what to
make of it. Setting it to 1 too means that we get rid of all units and we
measure length in multiples of the Planck length. But so far there is no
experimental evidence that the Planck unit is something special that could be
interpreted as some purely geometric property. I wouldn’t call it something
“physical” with what we know today.

~~~
tremon
_the actually geometric thing, that exists w /o resorting to some arbitrary
choice of units, is causality_

I can agree with that in principle, but continuing in that line of reasoning:
what remains is that the effects of an event ripple outward at a certain speed
(ignoring quantum entanglement for a moment). It is my impression that c
represents the upper limit of event propagation speed, and as such I would
classify it a physical property.

I'm a bit hazy about the exact physical implications of h-bar, but I thought
it represented the absolute lower bound of energy quantization. Whether that
is a real fundamental property or a consequence of underlying structure is yet
to be determined, I believe.

~~~
hansen
The term ’length’ in GR is pretty complicated and there is no such thing as a
canonical spacial distance between two events. There is no canonical splitting
of space-time into space and time, unless perhaps for very symmetric space-
times. E.g. we use the free falling galaxies in an isotropic universe as a
global clock and call the orthogonal complement ’space’, aka ’comoving
coordinates’.

Using the term ’speed’ in the sense of ’spatial distance per time’ implies
some non-trivial conventions. So the most accurate way to describe light rays
would be to say they are “light like curves” (the ones with zero velocity wrt
the Lorentian metric) which are exactly the geometric entities that describe
the causal past and future of events. So IMHO causality is the real physical
property of space-time and the ’speed’ of light is just a convenient way to
visualize it.

ℏ is probably best described as fixing the units for angular momentum. The
energy spectrum of QED is continuous. And using the properties of free
particles feels a bit fishy as they are just an approximation.

