Strong Force

[Fallingstar1971]

Does the strong force taper off with distance like gravity?

Star

 

[azure_infinity]

Well, it is thought that in the very early universe that the SNF was combined with the others in the EMF, and in this way, it would propagate at the speed of light, and with a quadratic fall-off like electromagnetism.

Since the SNF is what it is today, it operates on Planck scales, and it is no more meaningful to say that it has a "falloff" as it is to say that it has a consise boundary with no falloff inside that boundary.

 

[Saiph]

....right. Can't make much sense out of Azure's reply.


The strong force does drop off over distance, but not like gravity. It's much, much sharper of a decline. Despite being immensely powerful, it's affects don't really reach beyond the nucleus of an atom.

 

[darkmatter4brains]

....right. Can't make much sense out of Azure's reply.


The strong force does drop off over distance, but not like gravity. It's much, much sharper of a decline. Despite being immensely powerful, it's affects don't really reach beyond the nucleus of an atom.

Saiphs response is correct, but there is a catch - quark confinement. The details are complicated and I forgot most of them, so did a quick search and came up with this:

http://hyperphysics.phy-astr.gsu.edu/hb ... or.html#c1

"A property of quarks labeled color is an essential part of the quark model. The force between quarks is called the color force. Since quarks make up the baryons, and the strong interaction takes place between baryons, you could say that the color force is the source of the strong interaction, or that the strong interaction is like a residual color force which extends beyond the proton or neutron to bind them together in a nucleus.

Inside a baryon, however, the color force has some extraordinary properties not seen in the strong interaction between nucleons. The color force does not drop off with distance and is responsible for the confinement of quarks. The color force involves the exhange of gluons and is so strong that the quark-antiquark pair production energy is reached before quarks can be separated. Another property of the color force is that it appears to exert little force at short distances so that the quarks are like free particles within the confining boundary of the color force and only experience the strong confining force when they begin to get too far apart. The term "asymptotic freedom" is sometimes invoked to describe this behavior of the gluon interaction between quarks.

 

[Saiph]

now you've gone and made my head hurt.

Expect a bill for 2 advil in the mail....

 

[darkmatter4brains]

now you've gone and made my head hurt.

Expect a bill for 2 advil in the mail....

only 2! I had to take 4 after reading that :lol:

 

[bushwhacker]

yikes, i bought a whole bottle

 

[Fallingstar1971]

I ask mainly due to the scale, and whether or not the strong force could be gravity itself working at quantum scales.

Star

 

[azure_infinity]

You probably read that here:
http://arxiv.org/html/physics/0010059

I don't accept it though, for whatever that's worth. :mrgreen:

 

[Fallingstar1971]

Not before you posted it....no.

I was just thinking, gravity causes galaxies and planets and stars and dust and gas to attract to one another, the closer the objects, the stronger the attraction.

The SNF causes protons to stick together

But.......if protons attract through gravity, why do massive atoms not have electron/nucleus collisions. If the attracting mass increases, but the speed of the inner electrons in orbits one and two stay the same, then gravity should cause the electrons orbit to decay.

On the other side of the coin, if I decrease the mass of the nucleus without changing the speed of the electrons then the atom should fly apart.

*sigh*

So I guess it cant be gravity after all

Could electrons just exist free in space? In other words, If I stick 8 protons and 8 neutrons together, will they attract 8 electrons automatically to create Oxygen? Is there a way to test this? Or are there examples in nature?

Star

 

[MeteorWayne]

The gravitational attraction between protons is swamped by the Strong Force, and the reulsion of the electromagnetic force.

Seems like you really need to do some research on the standard model of physics. It will take forever for us to teach you everything one question at a time.

 

[Fallingstar1971]

I am aware of how atoms and gravity work, and how the SNF is an independent phenomena than gravity. I know that the SNF works best at point blank range. I know that gravity is directly related to mass. I went to trade school to be an electrician. That makes me familiar with the electromagnetic force.

What I don't understand is that if you don't want to teach, then you don't want to answer questions. If you don't want to answer questions, then stop responding or better yet, find a new job! You really have no business in a forum designed to teach and answer questions.

So while I may need some research on standard models, you need some research on what you really want to do with your life. I can point you in the right direction by telling you NOT to be a teacher.

Star

 

[darkmatter4brains]

But.......if protons attract through gravity, why do massive atoms not have electron/nucleus collisions. If the attracting mass increases, but the speed of the inner electrons in orbits one and two stay the same, then gravity should cause the electrons orbit to decay.

To give you an idea of why gravity doesnt play much of a role when you start to think about things that are the size of atoms, check out the relative strenghts of the four forces:

Strong --> 1
Electromagnetic --> 1/137
Weak --> 10^-6 or 0.000001
Gravity --> 10^-39 or 0.000000000000000000000000000000000000001

As you can see, gravity is incrediby weak compared to the strong and electromagnetic forces. Now, check out the relative ranges:

Strong --> 10 ^-15
Electromagnetic --> infinite
Weak --> 10^-18
Gravity --> infinite

You can see just how quickly the strong and weak forces fall off, and how gravity predominates on large scales. But, wait, the EM force is also infinite, so seems like that would predominate over gravity on large scales, right? Well, on large scales, most objects are neutral, so the EM force doesn't come into play here.

The reason you don't really have electron/nucleus collisons is because of quatum mechanics. When you get down on small scales everything is quantized. The electron can only exist in certain discrete orbits, NOT just any orbit. As a result, any small-scale bound system, such as an atom, will have a ground state, or lowest allowed orbit. The electron will not orbit in any closer than this.

Now that's not to say an eletron and proton will not ever come into contact. In the collapse of a neutron star, electrons and protons are essentially squeezed into each other to create neutrons. But this is an extreme environment.

Could electrons just exist free in space? In other words, If I stick 8 protons and 8 neutrons together, will they attract 8 electrons automatically to create Oxygen? Is there a way to test this? Or are there examples in nature?

Yeah, the oxygen atom can exist with anywhere between 0 and 8 electrons. These are just different states of ionization of the oxygen atom. The hotter the temperature, the more likely an atom may be ionized to some extent. Cool things down and let an electron pass by and it will fall into an orbit on that atom. Heat things up again and it may get torn off.

A neat example of free electrons and ionization is the re-entry of space vehicles like the shuttle. You know that "blackout" period they have? This is because, during reentry, the vehicle is coming in so fast and experiencing so much friciton with the atmosphere, that it heats it up to an extent that it actually ionizes the "air" around it. All the free electrons created during this period carry a negative charge and interfere with EM communications.

Ultimately, all the four forces really are the same force. They only seem different to us because of the low energy regime we live in. If you plot the coupling constants of the forces versus temperature/energy they appear to merge at extremely high energy regimes like the early Universe.

 

[Saiph]

On your last bit, Electrons can and do exist freely in space. No problem there at all.


Also, if you stick 8 protons & 8 neutrons together, you get Oxygen. No need for any electrons at all.

The presence of electrons around the oxygen nucleus dictate how it behaves chemically, but it is still fundamentally oxygen with 0 electrons, or 8. Or 6....

 

[rabraha3]

Back on topic, Darkmatter4brains touched upon the behavior of the strong nuclear force. It has a finite range (slightly larger than the size of a proton/neutron). Outside that range, the strong nuclear force has zero effect. Inside, however, the force is similar to a spring. The further apart two particles get, the stronger the force and visa versa. The closer the particles, the weaker the force. This is what was meant by quark confinement. By the time two quarks are separated enough to bring them outside the influence of the strong nuclear force, enough energy has been put into the system to spontaneously create more quarks which immediately pair up with the original "separated" quarks.