What happens in a particle accelerator?

  • #1
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I always hear that when protons slam together, they annihilate into pure energy. Then that energy sometimes reforms into other particles. How does that make any sense? Energy is just an arbitrary mathematical quantity.
 

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  • #2
ZapperZ
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I always hear that when protons slam together, they annihilate into pure energy. Then that energy sometimes reforms into other particles. How does that make any sense? Energy is just an arbitrary mathematical quantity.

What ever gave you the idea that energy is an arbitrary mathematical quantity? The conservation law means nothing to you?

Zz.
 
  • #3
SteamKing
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I always hear that when protons slam together, they annihilate into pure energy. Then that energy sometimes reforms into other particles. How does that make any sense? Energy is just an arbitrary mathematical quantity.

That's what the guy said after he got struck by lightning.
 
  • #4
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I mean it isn't anything physical. It's just the ability to something. The way I've heard this explained, there is a sort of physical energy that floats around after the collision and just sometimes transforms into particles.
 
  • #5
ZapperZ
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I mean it isn't anything physical. It's just the ability to something. The way I've heard this explained, there is a sort of physical energy that floats around after the collision and just sometimes transforms into particles.

It isn't anything "physical"? Give me an example of what you think is "physical", and I'll show you "energy".

We can explain what actually happens in a particle collider (this is not a particle accelerator question). However, what occurs in such a collision has nothing to do with your superficial understanding of the importance of energy concepts. It IS physical. In fact, Quantum Mechanics is built upon such a thing (look at what is involved in setting up the Schrodinger equation). So do you think your electronics actually work based on something that isn't physical? That heat you feel from the sun isn't physical?

Zz.
 
  • #6
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I feel like you know what I mean though. You don't get hurt by energy when struck by lighting, you get hurt by electrons flowing through your body, which is an imperfect conductor, bumping into things, which increases the atom's and molecule's kinetic motion. This irregular heat, or kinetic motion, is part of what harms you. A calculation of total energy will tell you how much current, the physical process, will flow through your body. A while ago i asked why string theory was sometimes explained in terms of vibrating strings of energy. The posters came to a conclusion that it was for lack of a better word, and that energy was not a physical entity.
 
  • #7
ZapperZ
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I feel like you know what I mean though. You don't get hurt by energy when struck by lighting, you get hurt by electrons flowing through your body, which is an imperfect conductor, bumping into things, which increases the atom's and molecule's kinetic motion. This irregular heat, or kinetic motion, is part of what harms you. A calculation of total energy will tell you how much current, the physical process, will flow through your body. A while ago i asked why string theory was sometimes explained in terms of vibrating strings of energy. The posters came to a conclusion that it was for lack of a better word, and that energy was not a physical entity.

And you buy that?

What if I tell you that energy is a physical quantity? Why won't you buy that? And I'm basing it on something we have verified! String theory has no experimental/empirical verification! You put your eggs in such an uncertain basket and called it a day? Is this rational? This is what happens when you try to run before even learning how to walk.

Look up in a classical mechanics something called "Lagrangian/Hamiltonian mechanics". It is ALL energy! It is as valid and as physical as forces, charge, etc.

You should had just asked what happened in a particle collider. Prefacing it with your lack of understanding of what energy is and how important it is has clearly derailed this thread.

Zz.
 
  • #8
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In your example, electronics work due to the electromagnetic force and the fact that electrons repel each other. The higher the electron pressure, voltage, in a sense, the more they physically want to get away from each other. Electricity is just a domino effect of electrons moving within a conductor. Energy is just a way to quantify what we will see happen in the physical world.
 
  • #9
ZapperZ
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In your example, electronics work due to the electromagnetic force and the fact that electrons repel each other. The higher the electron pressure, voltage, in a sense, the more they physically want to get away from each other. Electricity is just a domino effect of electrons moving within a conductor. Energy is just a way to quantify what we will see happen in the physical world.

Electronics work due to quantum mechanics. Quantum mechanics, if you care to learn it, is all about understanding the kinetic and potential energy term in the Hamiltonian. That is the starting point in describing any system.

"Forces" are directly related to energy. If you think energy is unphysical, and then so are forces.

Zz.
 
  • #10
ZapperZ
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If you think that energy is an arbitrary mathematical quantity, then yes, you will never make any sense out of what occurs in a particle collider. In fact, you will never make any sense out of practically every single phenomena you see.

So I think that answers your original question.

I'm done.

Zz.
 
  • #11
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Of course I want to learn it. I'm just giving you examples of how I am approaching the problem.

Can you give me an example of energy as a physical entity?

edit: I see you mentioned a force as an example of a physical manifestation of energy, but the electric charge of an electron, for example, doesn't change depending on the system your looking at, right? The fundamental charge is the fundamental charge. But the calculated number for the energy of a moving baseball could be trillions of joules relative to a distant galaxy, or fractions of a joule relative to earth. Hopefully you see where I'm getting a little confused.
 
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  • #12
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... well that was a friendly encounter.
 
  • #13
Drakkith
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I always hear that when protons slam together, they annihilate into pure energy. Then that energy sometimes reforms into other particles.

I won't get into whether or not energy is "physical" or not.

I will say that at no point is there energy just "floating" out there and it "sometimes" reforms into other particles. ALL of the energy of the collision is conserved. Some of it is turned into mass as particles are created, some of it is given to these particles as kinetic energy, and the rest is radiated away as EM radiation.
 
  • #14
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I won't get into whether or not energy is "physical" or not.

I will say that at no point is there energy just "floating" out there and it "sometimes" reforms into other particles. ALL of the energy of the collision is conserved. Some of it is turned into mass as particles are created, some of it is given to these particles as kinetic energy, and the rest is radiated away as EM radiation.

See this response makes more sense to me. Which is usually the case with Drakkith :).

You can't point to an area in space and say, there is some energy. But I can point somewhere in front of me and say, right there is a gravitational force that permeates space of 'x' strength. Thanks for not being so stubborn Drakkith.
 
  • #15
Drakkith
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You can't point to an area in space and say, there is some energy.

Mmmm.....maybe. If that volume of space contains EM radiation we might be able to say that. And I don't even want to get started on things like vacuum energy...

Suffice it to say that this is a *bit* more complicated than one might think.
 
  • #16
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... well that was a friendly encounter.

Because you come off as arrogant and stubborn about topics you know almost nothing about.

Do you think an atomic bomb is physical? Have you ever looked into the physics of how nuclear fission or fusion works? Just because something isn't easy to put into words or a simple picture, doesn't mean it's not "physical".

You seem to think that electrons are physical and that they are somehow simple and easy to grasp. Yet if you actually knew anything about quantum mechanics, you wouldn't be so sure anymore. You just associate an electron with a little ball, and you base what you call "physical" on these unrealistic and vastly oversimplified pictures.

By your standards, if you actually spent the time to appreciate the complexity, then nothing would appear physical to you.
 
  • #17
Drakkith
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Let's stop the blame game here, please. This simply boils down to an argument over what is "physical" and what isn't, which is mostly pointless and will get the thread locked.
 
  • #18
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Not really, because by any definition you pick, if you want to classify something like an electron as "physical" (which is an example the OP used) then energy is physical too.

Honestly it's a silly question, but there are occasions where in simple models you have predictions which don't map onto the real world (for example, the non-vanishing heat capacity of an ideal gas at absolute zero). These things are "non-physical", but energy isn't.
 
  • #19
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I guess I'm just considering something that has coordinates in physical space as physical. Even with fundamental particles, isn't it the case that you can never know where an electron is in space? If so, doesn't that mean it is still somewhere in space, we just don't know? So what I guess I'm really asking is, can you point to somewhere that energy is located in 3 dimensional space?
 
  • #20
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I feel like I haven't expressed my ideas very clearly so i'll try one more time. The vocabulary I used was probably incorrect. Tell me if this statement is correct:

Energy is always in different forms. Photons, kinetic motion, curved space-time, ect. But there is no such thing as pure energy.

Like in star trek, they run into a cloud looking thing and Spock says it's comprised entirely of pure energy. What the hell is pure energy? haha.
 
  • #21
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Your view of energy might have been valid before 1905, when Einstein introduced special relativity theory and shown that E=mc2. Only after that particle physics was possible to emerge.
Energy is equivalent to mass, and therefore as physical as electrons, if not more so, even with your definition of physical
 
  • #22
Drakkith
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Energy is equivalent to mass, and therefore as physical as electrons, if not more so, even with your definition of physical

Energy and mass are related but they are far from being the same thing. Mathematical equations are not definitions.
 
  • #23
meBigGuy
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Nobody has even bothered to try to describe the "pure energy" given off by proton annihilation. Instead a simple question and incorrect declarative statement is met with childlike derision. Unfortunate, and certainly unprofessional. Seems like a problem to me.

As for an attempt at an answer:

First off, I don't think proton-proton collisions result in total conversion to pure energy. Please correct me (politely, please) if I am wrong.

Proton - antiproton annihilation likewise is not that simple. Read the wikipedia article on Annihilation.

To the extent that "pure energy" is given off by any particle collision, it is in the form of photons. A photon is a "packet" of energy --- pure energy. The energy in a photon is tied to its wavelength. It has a definite physical basis. For that you should read more about photons, and even more about particles (like, what are particles, anyway).
 
  • #24
Drakkith
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Really? I thought I answered that in my first post.
 
  • #25
meBigGuy
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sorry Drakkith --- your answer was good, and I always appreciate your effort to clarify. Obviously the poster did also.
 
  • #26
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I guess I'm just considering something that has coordinates in physical space as physical.
Then nothing is physical.
Even with fundamental particles, isn't it the case that you can never know where an electron is in space?
You cannot even be sure that there is an electron.

Energy is not an object in space, I think that is what you mean. Particles and fields (and quantum field theory combines both) can have energy.

Like in star trek, they run into a cloud looking thing and Spock says it's comprised entirely of pure energy. What the hell is pure energy?
That does not make sense, right.
 
  • #27
Dale
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http://www.thefreedictionary.com/physical

Physical: "adj ... 3. Of or relating to matter and energy or the sciences dealing with them, especially physics"

Energy is clearly "physical".

You are probably thinking of "matter". Energy is not matter, but it certainly is "physical".
 
  • #28
Dale
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I always hear that when protons slam together, they annihilate into pure energy.
That is incorrect. Whatever source you heard this from is wrong. There are many other conserved quantities besides just energy. There is momentum, invariant mass, spin, charge, etc. All of these quantities are also conserved, so you never get anything which could reasonably be described as "pure energy".

The important quantity in a particle collider is the invariant mass, not the energy. The particles that they produce in a collider are very massive, and because invariant mass is conserved you have to have a very massive system of particles to produce a massive particle. The invariant mass of a system of particles includes some of the KE of the particles in the system, so the reason for the high energy of the colliders is to produce a lot of invariant mass in a small system of particles.

If you have more questions about invariant mass, I would recommend opening a thread in the relativity forum.
 
  • #29
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http://www.thefreedictionary.com/physical

Physical: "adj ... 3. Of or relating to matter and energy or the sciences dealing with them, especially physics"

Energy is clearly "physical".

You are probably thinking of "matter". Energy is not matter, but it certainly is "physical".

Ooooh ok, maybe physical is the wrong word. An electron, photon, and neutrino are all examples of matter. Energy is not matter, it governs how matter behaves. It doesn't take up space. Is this accurate?
 
  • #30
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I think let's sum it up by saying something like this , there is matter like atoms , molecules charged particles etc.
Now with photons I'm not so sure as they are basically in the role of energy transfer which is the so called " non physical" part of physical objects.

In other words you have matter , which you can see touch and feel both with your body or with a microscope or whatnot and then that matter under the right conditions releases it's potential energy or interacts with other matter and that is where energy comes in and all the fields etc.

Take for example the electric field , imagine you have only one proton in the whole universe , now you can see the proton because it's a physical thing , you cannot see the field nor it's interactions because there is only one proton , add another proton which is also physical and voula , you now see that they both repel each other so at first moment you probably think magic but then you go through the 20th century and prove that it's nothing more than fields in action , so here is where field or photon or energy no matter kinetic, or electromagnetic becomes real and physical , because it has real applications and it distorts spacetime and matter like gravity and influences it.
A ghost wouldn't do that now would it ?
 

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