In the current Standard Model of physics, all matter is composed of quarks or leptons. They interact with each other by exchanging other types of particles, known as bosons, which carry the forces of nature.
Quarks are particles which interact via the strong nuclear force, and are only found bound together into composite particles called hadrons . The proton and neutron are both examples of hadrons. Although protons and neutrons are made up of the two lightest quarks (named "up" and "down"), there are six types of quarks which have been discovered, and we have reason to believe that there are no more types of quarks than that. The "Top" quark is the heaviest of the six quarks, and was only discovered recently.
Leptons do not interact via the strong nuclear force, so they can be seen on their own. There are also six kinds of leptons, the best known of which is the electron.
As far as we can tell so far, there is no evidence that quarks or leptons are made of smaller things. This, of course, does not mean that we are not looking for such evidence! If quarks and leptons were made of smaller particles that were orbiting each other, it might be possible to hit them very hard and bump them into higher orbitals, and then watch them decay the way excited atoms work. Some friends of mine were working on a study like this at my last experiment, but did not see any evidence of this happening.
There are many sites on the web with information about quarks, leptons, and particle physics. Here is one which I find particularly well written. A lot more information about the fundamental particles can be found at the web site of the Particle Data Group at Berkeley in California.
Of course, you can also contact me at silver@physto.se if you have any more questions.
I hope this helps!
CHAKI
― charleston charge (chaki), Tuesday, 15 March 2005 09:21 (twenty years ago)
one year passes...
three months pass...
Hi Chaki, do you still need a car? A year and a half ago I gave my car to a friend's son who was just learning how to drive and he just now decided he didn't want it because it's a standard and he doesn't want to learn how to drive a stick. Chicken shit! Anyway, my friend just called me and said she wants to know if I want to give it to anyone else. It's a '96 Honda Civic, a little beat up but it runs fine. E-mail me if you're interested.
And Happy New Year!
― Arthurrrrr (Arthur), Saturday, 6 January 2007 04:21 (eighteen years ago)
hey chaki, i hope you didn't mind me quoting rickie lee jones on your unicorn thread, it was just a dumb pun.
― estela (estela), Monday, 15 January 2007 10:02 (eighteen years ago)
oh no, it's totally cool. it just took a second for me to get it. im slow.
― chaki (chaki), Monday, 15 January 2007 17:08 (eighteen years ago)
seven months pass...