Particles, Particles, Particles...

[Loki]

From Bill Bryson in his book A Short History of Nearly Everything

"Today the particle count is well over 150, with a further 100 or so suspected, but unfortunately, in the words of Richard Feynman, 'it is very difficult to understand the relationships of all these particles, and what nature wants them for, or what the connections are from one to another.'"

 

To my understanding, these 150-250 particles are the real building blocks of our universe. Without considering string theory, these particles--as far as we can tell--cannot be broken down into smaller particles (correct?). So what does all this mean? At first we thought there was only protons, neutrons, and electrons. Then we discovered quarks. And now the particle count is up to 150!

 

It's probably best to take note of how many of these particles last not even a millionth of a second and may be completely irrelevant to nature and the universe.

 

comments?

[alt_f13]

Perhaps those particles that last for so short a period of time have no visible effects in the 4 dimensions we can see, and are merely byproducs of the forces we cannot see in other dimensions.

 

Does that make sense? For example something like the 'brane big bang theories. (But without considering string theory...hmm)

But of course you all considered that already right? Right.

[Erador]

could be that these 'particles' flow between fluctiuations in space time and gravity, tumbling between multiple universes.

but the obvoius question is...

what happnes to the particle after the millionth of a second.

does it just disappear?

or does it create itself into something else?

lifes full of mysteries

lol

[YT2095]

MAYBE, it`s a bit like Tachyons (hypothetical particles that are only said to exist at speeds greater than c)

allegedly they`re suposed to vanish too at velocities slower than C. could it be that they don`t VANISH as such, but break down to even smaller (undetectable) parts because the energy that displaces them wears off and they lose cohesion?

a bit like blowing up a stick of dynamite in reverse. we can just about see the stick (quark) but where does it go after it blows?

in reverse, we can make a lit stick of dynamite by applying enough energy, but with a fuse a millionth of a sec long, it`s soon gone again. I`ve probably explained it badly, I`ll get more coffee and think some more

[JaKiri]

Most of the particles are varying forms of the standard particles (eg. Tau neutrinos and the like), or different quark combinations.

[YT2095]

a bit like isotopes of an element you mean?

 

same element, different Neutron count?

[JaKiri]

More like different elements.

 

Same things making it up, different properties.

[aman]

Aren't the true differences in these particles the effects we try to document. They have consistant masses or no measurable mass, consistant electrical charges or no charge, consistant source, velocity, size, and lifetime. And some we still just guess at because data indicates they might be there.

It seems we still try to define the quantum universe in terms we apply to our reality. I like exploring these particles as only transistionally existing in our four dimension universe and that we will not understand them until we can see beyond the speed of light barrier. But that's just me.

Just aman

[YT2095]

didn`t someone once say also that simply observing some of these particles will have an effect on them also? was it Eisneburg?

I forget.

[Dave]

It depends on the circumstances. If, in a double slit experiment, you fire a single electron through one slit, one at a time, then the electron will somehow interfere with itself and create an interference pattern on a screen. However, if you try to observe this by putting observers on either one or both of the slits, then this effect will not happen.

 

Going back to what you were saying earlier, some of these particles can be useless. A pi0 meson, for instance, is composed of a pair of any quark-anti-quark combination (i.e. up, anti-up; down;anti-down, etc) and hence will annihilate itself after a very short period of time. However, I do think this can be used as an exchange particle in some circumstances.

[Sayonara]

YT2095 said in post #9 :

didn`t someone once say also that simply observing some of these particles will have an effect on them also? was it Eisneburg?

I forget.

Heisenberg's Uncertainty Principle:

 

Physics can be fun! - very little to do with Heisenberg, but there's some funny stuff on here. Like "Dubious fact of the month".

[YT2095]

Thats the fella

I remmeber reading something about that as a reason why a matter transporter (think star trek) could never be made to work.

[Sayonara]

Ahhh, but they had the Heisenberg Compensator to sort that out!

[YT2095]

LOL, I`ll take your word for it, I`m not really that into star trek tbh. and certainly couldn`t envisage how such a device could be made to work. sounds good in a film I supose

[Dave]

I like star trek. They just invent random words/terms to make it right

 

They asked a production guy once: "How does your Heisenburg Compensator work?"; he replied "Very well, thanks"

[Sayonara]

So it would seem.

 

Things hardly ever go wrong :-D

[YT2095]

thinking about particles and observation effecting them... it seems clear that we couldn`t observe a photon, because it would need to hit your eye or instrument, that would effect it for sure! but I wonder what happens to a photon after that? does it "die" or vanish? I know some of them generate energy again like in a photovoltaic cell, but what happens to it`s journey after?

just a though

[Dave]

A photon is just a packet of energy. When it hits an atom, its electrons tend to either escape (and hence the atom becomes ionised) or they go to higher energy levels which results in the emission of more photons.

 

Also bear in mind that the frequency of a photon determines whether it is visible or not.

[aman]

Does a photon actually collide or does it reach a threshold distance wich effects its stability? I can't imagine on the quantum level anything actually touching.

Just aman

[Dave]

They don't collide as such, but exchange other particles (known as exchange particles, heh). Or that's what a-level physics has taught me anyway.

[JaKiri]

Photons ARE an exchange particle.

[YT2095]

so taking it to it`s ultimate conclusion, the universe would just end up as a whole bunch of photons eventualy?

[Dave]

No, they don't all decay down to photons. Photons are just a way of conserving energy (and also are exchange particles for the electrostatic force).

[uscphysics]

Loki said in post #1 :

So what does all this mean? At first we thought there was only protons, neutrons, and electrons. Then we discovered quarks. And now the particle count is up to 150!

 

Quarks make up these particles. similar to the way water is always made up of 2 H and 1 O(well untill the recent debate) except it is the quarks that seem to be the building blocks for the particles(in a very simple manner).

[Severian]

Hi guys - sorry about the post above (I wanted to check if I could post, thinking I would edit it, but can't find the edit button.....(I can be a bit thick sometimes))

 

Anyway, I wanted to comment that 150 is a little unfair. First of all, the extra particles are not particles in the Standard Model - they are particles introduced by Supersymmetry. Supersymmetry introduces a new particle for every particle we have in the Standard Model: for every fermion we get an extra boson and for every boson we get an extra fermion. If I remember correctly the Minimal Supersymmetric Standard Model then has 123 particles (or thereabouts).

 

But that is not very fair either because supersymmetry has also introduced a new fermionic 'dimension' into the game, and the new particles are really just the component of the old particles in the new femionic dimension. So they are really just different facets of the old particles and not new ones at all!