What do you mean by "they are introduced"?Orodruin said:What do you mean by "useless"? Particles do not have an underlying "purpose" in physical theories. They are introduced because they are needed to provide a good description of how nature works. Asking if there is a "grand scheme" is a religious and philosophical question rather than a physics question.
This is not true. There is no deeper meaning in quarks and electrons forming atoms and it is not their "purpose" to do so. They have properties which make them do that, which in turn makes them a good description of observations.Brunolem33 said:What I mean, for example, is that we have the quarks and the electron, and that together these particles form atoms.
And here you are ore-supposing that there is an electromagnetic force. The implication is in the other direction, photons are introduced because they give a good description of observations, among them the emergence of the electromagnetic forces. There is no deep purpose in the existence of the EM force, it is just a good description of observations.Brunolem33 said:Or there is the photon which carries the electromagnetic force.
Again, this is the wrong question to ask. Any concept in physics simply would not be there if it was not to describe observations, if nothing else the observation of the particles themselves. Physics is not about assigning meaning.Brunolem33 said:Now, are there other particles that science has been able to identify, but to which it was not able to assign a role?
By definition no. A universe where they did not exist would be intrinsically different simply by the fact that it does not have the same particle content.Brunolem33 said:In other words and as far as we know, the universe would remain the same if these "unassigned" particles didn't exist.
I am not sure I understand all this.Orodruin said:Physics (and science in general) is about creating a model which describes observations, nothing else. We introduce concepts such as energy, particles, and waves because it gives a good description of what we can observe. If you want to say that these concepts are "real" in any sense of the word, you are leaning more to the philosophical than to the physical side of things.This is not true. There is no deeper meaning in quarks and electrons forming atoms and it is not their "purpose" to do so. They have properties which make them do that, which in turn makes them a good description of observations.And here you are ore-supposing that there is an electromagnetic force. The implication is in the other direction, photons are introduced because they give a good description of observations, among them the emergence of the electromagnetic forces. There is no deep purpose in the existence of the EM force, it is just a good description of observations.Again, this is the wrong question to ask. Any concept in physics simply would not be there if it was not to describe observations, if nothing else the observation of the particles themselves. Physics is not about assigning meaning.By definition no. A universe where they did not exist would be intrinsically different simply by the fact that it does not have the same particle content.
We can manipulate things and we call some of those things particles. For other things, we say "they are made out of particles". That is our description. It is possible to find different descriptions for the same observations.Brunolem33 said:How can particles be only some kind of concept if we can actually manipulate them and get something out of these manipulations?
A particle which does not interact at all with anything else in any way would be completely unobservable.Brunolem33 said:From the elementary particles that science has been able to identify until now, are there any that appear to be useless, at least as far as we know?
Or do all the identified particles play a role in the grand scheme of the universe?
Not totally true, you can observe them indirectly in particle accelerators. A stable particle that does not interact with anything well be detectable as a collision of two protons that produce seemingly nothing as a result, or a slew of particles who's energy doesn't add up to the original amount of energy. An unstable particle would also be detectable after it decays, you'd see a a spray of particles seemingly coming out of nothing.rootone said:A particle which does not interact at all with anything else in any way would be completely unobservable.
I agree with that, what I meant was that proposing a particle which has no effect on anything, not even indirectly, is meaningless,newjerseyrunner said:Not totally true, you can observe them indirectly in particle accelerators. A stable particle that does not interact with anything well be detectable as a collision of two protons that produce seemingly nothing as a result, or a slew of particles who's energy doesn't add up to the original amount of energy. An unstable particle would also be detectable after it decays, you'd see a a spray of particles seemingly coming out of nothing.
Sometimes "particles" come out of math that aren't real things. Spinon for example, I tend to think of the most elementary particles more of abstract concepts than actual things. Yes, a particle with absolutely no interactions, no structure, or energy, is perfectly valid as far as I know. You can always add zero or multiply by one.rootone said:I agree with that, what I meant was that proposing a particle which has no effect on anything, not even indirectly, is meaningless,
since as far as physics is concerned it makes no difference whether it exist or not.
(A bit like adding the term '+0' to the end of a math formula)
How are you planning to produce a particle which does not interact at all in a particle accelerator?newjerseyrunner said:Not totally true, you can observe them indirectly in particle accelerators.
No it will not, because it will never be produced in a proton-proton collision. If it does not have any interactions at all, in particular it does not have any interactions with the proton constituents. There is a difference between "very weak" and "non-existent".newjerseyrunner said:A stable particle that does not interact with anything well be detectable as a collision of two protons that produce seemingly nothing as a result
Agreed, I retract my posts.Orodruin said:How are you planning to produce a particle which does not interact at all in a particle accelerator?No it will not, because it will never be produced in a proton-proton collision. If it does not have any interactions at all, in particular it does not have any interactions with the proton constituents. There is a difference between "very weak" and "non-existent".
Backing my initial question was something else.rootone said:I agree with that, what I meant was that proposing a particle which has no effect on anything, not even indirectly, is meaningless,
since as far as physics is concerned it makes no difference whether it exist or not.
(A bit like adding the term '+0' to the end of a math formula)
Why should there be millions of different kinds of particles?Brunolem33 said:If these particles were created randomly, which was supposedly the case, there must have been millions upon millions of different kinds of particles created
Because if that was not the case, one could wonder about randomness when it comes to the creation of the universe.mfb said:Why should there be millions of different kinds of particles?
Purpose implies intention ... by whom? ...Brunolem33 said:... would be of no use for this purpose ...
I don't see the philosophical aspects in suggesting that there could be much more kinds of particles than those already observed?Vanadium 50 said:I think this is somewhere between "philosophy" and "wrong". Can we maybe restrict the discussion to what can be addressed by the scientific method?
Maybe I used the wrong word...what about replacing it with creation?rootone said:Purpose implies intention ... by whom? ...
What about dark matter?rootone said:Ah, well there do exist reasonable theories of the existence of particles beyond those which are known and are part of the standard model.
However these predict the possibility of particles, or objects, which DO interact one way or another with the known ones, or are components of them.
String theory, Supersymmetry.
Brunolem33 said:I don't see the philosophical aspects in suggesting that there could be much more kinds of particles than those already observed?
Thanks.rootone said:
I already answered the question about purpose previously, and offered to replace this word with creation.Vanadium 50 said:
- You are ascribing purpose.
- You are claiming millions of kinds of unobserved particles with no evidence. Why not one or two?
Well the odds are better than zero, since 'our' Universe exists.Brunolem33 said:What would be the odds of a cooling plasma randomly giving birth to a small number of kinds of particles, all of them fitting in the creation of our universe?
You cannot just quote randomness. It is not a valid reference. The randomness that appears in for example quantum mechanics still has rules to it. So does the creation of particles in the early Universe. When physicist propose particle candidates for dark matter they must in fact be very careful in providing a mechanism through which it can be created in the early Universe. What you seem to be talking about is not randomness but complete and utter chaos.Brunolem33 said:Because of randomness.
Actually randomness, or rather chance (see reply above), is quite the opposite of design, intelligent or not.rootone said:I think it could be that you are looking for 'Intelligent design', another meme for 'God/Allah' .. etc.
That isn't science, it's mysticism, and it explains nothing (except irrational behaviour of some people)
Thank you for correcting my vocabulary (being French and not a physicist doesn't help, but is no excuse for not paying attention).Orodruin said:You cannot just quote randomness. It is not a valid reference. The randomness that appears in for example quantum mechanics still has rules to it. So does the creation of particles in the early Universe. When physicist propose particle candidates for dark matter they must in fact be very careful in providing a mechanism through which it can be created in the early Universe. What you seem to be talking about is not randomness but complete and utter chaos.