I understand that, however I imagine that the mathematical algorithms and terms used to describe Newtonian mechanics are completely different to the algorithms that describe relativity. Is it not the case that the algorithms that describe "the standard model" can only be tweaked or modified so far before you need to throw them away and start with new algorithms and different terms? Otherwise isn't supersymmetry just a heavily tweaked version of the standard model?
Newtonian mechanics isn't as different from relativity as you think - if you set velocity to zero, the equations governing special relativity are identical to Newtonian mechanics. Isn't supersymmetry just a heavily tweaked version of the Standard Model? Sure. But that tweaking makes it different enough that it no longer makes sense to refer to it by the same name (at least in most cases; the
Minimal Supersymmetric Standard Model is close enough that it does keep the name). Some approaches, such as string theory, do pretty much throw everything out and start from scratch, but that's not the only way to come up with something new.
Ok. You're going to have to explain that one. My understanding is that a particle and it's anti-particle would annihilate each other and photons obviously don't annihilate each other. The concept of something being it's own anti-particle doesn't make sense given how I understand anti-matter to work. (Again, please excuse my scientific illiteracy - I'm sure this must seem an obvious question to the initiated).
There's a decent explanation
here. In short, photons
do annihilate with each other, it's just not a common event due to small collision cross-sections and other effects. The important thing with respect to the general question is that antimatter is not defined by annihilation, it's a consequence of quantum physics - the equations that predict regular matter have symmetric solutions that correspond to almost identical particles with opposite charge. For neutral particles, that means that both solutions are actually identical - the particle and antiparticle are the same thing.
It's similar to quadratic equations always having two solutions. For example, x
2 = 1 has solutions of 1 and -1. x
2 = 0 also has two solutions, but they're both 0. That may just seem to be a bit of meaningless nitpicking when you learn about it in maths classes, but it's important when it comes to particle physics because having photons and antiphotons both acknowledged as solutions has physical meaning even though they're the same thing.
There are other mechanisms/explanations that also contribute to the mass of particles? (I mean I understand that relativity implies that mass is dependent on velocity, but I suspect there's more to it than that?)
The Higgs mechanism was originally developed to answer the problem that without it, electroweak theory (it hadn't developed to the standard model by this point) predicted that the W and Z bosons had zero mass. But this was a problem specifically with getting the weak force involved - we could already account for the masses of things like electrons via gauge theories that didn't try to unify electromagnetism with the weak force. It's not as simple as:
Standard model without Higgs - no masses
Standard model with Higgs - everything has mass
The Higgs mechanism and its consequences are just one part of the whole puzzle. Things wouldn't work properly without it, but it's really no more fundamental or important than any other part, it just happens to be the most recently confirmed.
Perhaps I'm reading you wrong, but the paragraph above implies that even if we understood the Higgs perfectly, we still wouldn't necessarily understand why matter has mass? We would only understand why the masses they have are the values they are - is that correct?
Well yes, but that's not really a point I was trying to make. If anything, that's more philosophy than anything else. No theory can really answer
why things are the way they are. We can describe how the universe works and what the properties of things in it are, but we can't say why they are that way rather than something else.
Note that I used the term
fundamental particles. We have lots of uses for all kinds of composite particles, starting with protons and neutrons and then combining them with other things to produce pretty much everything we do. But other than electrons and photons, I'm not aware of any technology resulting from the discovery of a fundamental particle, and even in those two cases many of the uses ultimately stem from empirical testing prior to the discovery of the actual particles - we had electric lights well before we knew what was going on at the particle level, or even that there was a particle level at all.
Obviously I'm not saying particle physics is useless; that would be rather hypocritical given my job. It's just that new discoveries in particle physics do not tend to lend themselves to immediate technological use. It's been nearly a century since we last discovered a particle that has actually been used to do something practical. We've discovered a whole lot more since then, but while things like computers rely very much on the associated advances in physics, the particles themselves haven't led directly to anything.
I just want to learn!
