Why 1/137 is important?

[Martin]

when relativity is quantized you get a bunch of plumbing connectors able to fit a new universe onto the bottom of a black hole.

 

the bigbang and blackhole singularities (breakdowns of ordinary Relativity) go away and you get to connect the bottom of a black hole to the beginning of a new universe

 

Leonardo Modesto

"Disappearance of the Black Hole Singularity in Quantum Gravity"

http://arxiv.org/gr-qc/0407097

 

So you get this monstrous plumbing nightmare Multiverse where a typical universe has millions of black holes form sometime during its history and each one of those buds off and makes a baby universe which then expands and has black holes of its own.

 

And one of the dominant numbers in all these universes is 1/137-----that is the logical consequence of Smolin's hypothesis that the fundamental numbers dont change very much as you go thru a hole into a new universe.

 

Because it being 1/137 and not a fraction of percent different like 1/138 or 1/136 helps a universe have lots of babies.

 

This is smolin's Multi and he didnt wait for Modesto. he had advance notice of getting rid of the blackhole singularity so he knew someone would do what Modesto has done and he just went ahead and conjectured and challenged people to shoot it down. Smolin Multi does make testable predictions (like about pulsar masses) so you can experimentally shoot it down.

 

OK so we should understand this number 1/137.

It is a key feature of the universe and on the short list of fundamental constants that really matter, and maybe it evolved a la Smolin Multi, or maybe it did not and there is some other explanation that will come up.

 

Right now Smolin has the leading candidate explanation of why it is what it is.

 

Lee Smolin

Scientific Alternatives to the Anthropic Principle

http://arxiv.org/hep-th/0407213

 

What is 1/137? It is called alpha, and also called "fine structure constant".

considerable evidence has accumulated in the last 2 or 3 years that it has NOT EVER changed in the history of the universe although there was some little speculation and buzz a few years earlier that it might have changed

slightly. Even when that was fashionable the estimated changed did not amount to much so we may as well take it to be constant.

 

What is this number? does anyone want to give a brief exegesis?

[Martin]

for starters, everybody should know the Newton gravitational constant and the Coulomb constant

 

they tell you the force between two charges (or "masses" in gravity case) a certain square distance apart

 

Force = constant times product of charges/distance square

 

[math]F = G \frac{MM'}{R^2}[/math]

 

[math]F = k \frac{QQ'}{R^2}[/math]

 

in electricity Q is the letter for charge

in gravity M is the letter for mass, sort of the charge that goes with gravity

 

to find the force between two point-charges you multiply the two charges together and divide by the square distance---and you multiply by the appropriate constant.

 

it is terribly basic, the constant k here is called Coulomb, just like the constant G is called Newton constant. Monsieur Coulomb. Henry Cavendish got it first, around 1798 IIRC, but Coulomb published first.

 

G and k are fundamental proportions in your universe

 

 

alpha, 1/137, is the value of the Coulomb constant in nature's units

 

1/137 is the value that Coulomb's constant takes on if you express it in Planck units with the charge on the electron serving as the unit charge.

 

There is more to say. Would anyone like to do a little exposition about the fine structure constant?

[Primarygun]

[math]F = k \frac{QQ'}{R^2}[/math]

what's that?

Is it the force created by magnetism of particles?

[Martin]

what's that?

Is it the force created by magnetism of particles?

 

nearly right

was that just a lucky guess?

realistically, if you have to ask then this thread is probably not cut out for you, Gun. I am not teaching a review of basic physics in this thread.

 

JaKiri and various others could set up a basic physics review thread.

Maybe you should ask them to do it, or whoever you like listening to.

 

Look, in the next thread I will offer an explanation. I have to at least try. But I expect you wont like it so ask JaKiri about Coulomb's Law of Electrostatic Attraction/Repulsion. Or Sayonara.

[Martin]

we all the time experience static electicity things sticking to each other raising hairs on back of my hand, picking up bits of lint, giving shocks on a thick rug

 

basic law is two charges attract or repell with a certain force which you can calculate

 

western civilization is based on the idea that you can use algebra to calculate things and if you dont like to do that screw you---this is the fundamental tenet.

 

so the basic act of the communion with nature is to calculate the force.

 

it is very simple. You just multiply the two charges together and divide by the square of the distance separating!

 

but then there is this constant called Coulomb you have to also multiply in to make it come out.

 

Gun I worked an example of coulomb law for you in another thread:

http://www.scienceforums.net/forums/showthread.php?p=73343#post73343

[Primarygun]

Gun, I enjoy having my nick name!

It seems that you are deeply pofessional in physics, aren't you?

What made you have an idea of 1/137?

[Martin]

Gun' date=' I enjoy having my nick name!

It seems that you are deeply pofessional in physics, aren't you?

What made you have an idea of 1/137?[/quote']

 

it was not my idea

Richard Feynmann said every physicist should take piece of paper

and write 1/137 on it

and put it up on the wall in his study or workspace

to remind himself to always be wondering

why 1/137 is what it is, and not something slightly different

 

IIRC that is in the popular book QED, or maybe some other book,

i cant remember

 

dammit Gun I am anonymous---I dont have a profile.

 

the fine structure constant is one of the short list of most basic

numbers that make our universe be how it is, and not some other way.

It is not my idea. It was originally Sommerfeld idea around 1920, I think.

Anyway it is much older than Feynmann

 

people dilute the mystery of this number by talking like "that is not the real number, 1/137 is the low-energy limit that manifests another deeper number" but it is all the same mystery and the easiest way to get a handle on the mystery is to look at 1/137.

 

I read in SciAm one time that if 1/137 were a little different then when they tested the H-bomb in the Pacific there would have been a chain fusion reaction and all the hydrogen in the water of the ocean would have fused into helium like one big H-bomb.....it is the number which, by being right, causes 92 stable chemical elements to exist and not to be always decaying radioactively or fissioning and fusing one kind into another. What a horrible thought. The SciAm author was obviously trying to make a point but he went a bit over the top with his imagery, dont you think?

[Martin]

For physics, as I see it, this moment in its history is

characterized by an encounter with the absolute numbers

and efforts to understand why they are what they are

 

the particle Standard Model has about 26 pure numbers

(this is taking Planck units as the units to express masses and stuff)

 

and cosmology Standard Model has about 10 pure numbers

 

so that is why Smolin says there are roughly 35 'dimensionless parameters" which we need to explain

(see his "Scientific Alternatives to the Anthropic Principle" essay)

 

and it doesnt hurt to just look at the top 3

because that shows the situation in a nutshell.

 

Physics is encountering and being forced to account for

these three numbers

 

fine structure constant 1/137

planck proton mass ratio 13E18

cosmic length scale 2.7E61

 

 

the "cosmological constant" in this context just means the inverse square of the cosmic length scale-----and we dont even rightly know what value to attribute to it since we only just ran smack into it in 1998 with the data on accelerating expansion.

I just picked the length scale to be roughly what Smolin says, so if you take its inverse square you get what they estimate for the cos. const. or

"darkenergy"---it is pretty obscure but there seems to be some large length scale in the cosmos

the other two are more straightforward and have been around in human ken longer-----1/137 and the reciprocal proton mass.

 

 

the reciprocal of the proton's mass is 13E18, that is 13 quintillion, and

nobody has yet explained this number, why it is that.

 

A couple of years ago FrankWilczek, an eminent theoretical physicist, had a series of 3 articles in Physics Today about the number 13E18 and efforts to understand it.

They are online if anybody wants.

 

String theory has since January 2003 been thrown into some confusion by the number 2.7E61

Just one number will do it---in this case it was the cosmological constant.

IMO the important thing now is to confront the basic absolute numbers

and realize how ignorant we are and see what, if anything, can be done about it

 

I am a physics-watcher and I chose to align my perspective with Frank Wilczek and Lee Smolin---so I see roughly eye to eye with them about this moment in physics history.

[swansont]

92 stable chemical elements to exist

 

81

[Martin]

81

 

good, Swanson, was hoping you might be around

[Martin]

Swanson, just to take a test-drive with the constants,

I think I can calculate the colors hydrogen glows

just using 1/137 and maybe 13E18

I might also need the number 1836 too, which I know you recognize

as the proton/electron mass ratio. right now not sure what it will take.

but those 3 numbers should be sufficient.

 

do you poo-poo this, or do you find it interesting

[Martin]

yes, the Hartree energy will be easy to calculate.

it is twice the ionization energy of the H-atom

and from there all the energy levels are approx. just 1/n²

 

so all I have to do is calculate the hartree in the natural unit, the planck energy unit.

 

that means divide the planck energy unit by 13E18, by 1836, and by 137²

 

planck energy is 2 GJ, so if we want we can get the answer in joules and compare it with what the NIST Fundamental Constants website says about the hartree.

[jana]

Interestingly, wolfgang pauli at one time turned to the kabbalah in attempts to gain insight into the value of the fine structure constant.

[Martin]

Interestingly, wolfgang pauli at one time turned to the kabbalah in attempts to gain insight into the value of the fine structure constant.

 

God jana, that is really interesting. you have earned your keep for a whole month.

 

now we dont have to consider any of those mediocre numerologist crazies. Because pauli has topped them all!

[swansont]

do you poo-poo this, or do you find it interesting

 

It's interesting to a point. But there's a point in all this where it crosses over from science to philosophy to mysticism, where I expect a link to Deepak Chopra and "Fine Structure Crystals for better quantum holistic living"

[Severian]

[math]alpha = \frac{e^2}{4 pi epsilon_0 hbar c}[/math] (sorry, I don't know how to do hbar in html...)

 

It is only 1/137 at macroscopic distances, and then it is really 1/137.03599976, so it isn't realy exactly 1/137. It also changes with energy - at energies of the W-mass for example it is approximately 1/128.

[Martin]

You give the correct conventional formula for alpha, here. I will rewrite it so as to be a little more legible. This is the definition I assume here:

 

[math]\alpha = \frac{e^2}{4 \pi \epsilon_0 \hbar c}[/math]

 

The value I use for most purposes is 1/137.036, because it is a little more accurate than 1/137, and I really don't need all the accuracy of 1/137.03599976.

 

You are correct that at very high energies and short distances alpha increases. this is a good point to make:

 

It also changes with energy - at energies of the W-mass for example it is approximately 1/128.

[Severian]

Yeah - it looks a bit crap, but I can't figure out how to edit these posts.....

[Cap'n Refsmmat]

If you want to edit it, there's a button near the lower right corner of your post that says "Edit".

[Severian]

No there isn't - I only have 'Quote' and 'Quick reply'....?

[Martin]

Severian, I still have a serious question. I assume you are familiar with Planck units. If you wanted to you could no doubt express some of the basic constants in physics in Planck terms, as opposed to the usual SI metric terms. what I want to know is this. Is it obvious to you that in Planck units the value of the Coulomb constant is alpha?

 

that is, taking the electron charge as the unit of charge.

 

If not obvious, can you at least prove it to yourself by a little algebra?

 

If not then I have some explaining to do---my approach to discussing such things is not working

[Cap'n Refsmmat]

No there isn't - I only have 'Quote' and 'Quick reply'....?

Are you sure it's your post?

Try logging out and loggin in. If that doesn't work, go to the bottom of the page to the "Posting Rules" thingy and see if it says you aren't allowed to edit your posts.

[Martin]

[math]alpha = \frac{e^2}{4 pi epsilon_0 hbar c}[/math] (sorry' date=' I don't know how to do hbar in html...)

 

[/quote']

 

Dont worry just start over and put a backslash in front of the greek letters and the hbar

 

then it looks

\alpha = \frac{e^2}{4\ pi \epsilon_0 \hbar c}

 

and it makes the right formula

 

[math]\alpha = \frac{e^2}{4 \pi \epsilon_0 \hbar c}[/math]

[Severian]

You can't derive the dimensionless constants this way but you should be able to see consistancy with units (or in other words you should be able to derive the unit dimensions of alpha.

 

Planck units are [math]c = \hbar = 1[/math], and since you know c and hbar in SI units you can write 1 metre in terms of c etc...

 

Looking at your earlier formulae, your problem could be that for gravity you are using masses in the numerator in one case, which are dimensional, whereas for electromag you are using charges which are not?

[Severian]

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Hmmm....