Everything around you is made of matter.... rocks, water, air, toothpaste, yesterday's leftovers, everything. All matter is made of molecules, and all molecules are made of atoms -- carbon, oxygen, hydrogen, silicon, the whole list from the periodic table. But... what are atoms made of? Scientists have figured out they're put together from a bunch of "elementary particles", some of which you may (or may not) have heard of. Electrons, neutrinos, photons, six kinds of quarks (up quark, down quark, strange quark...), muons, gluons, etc etc -- 12 particles in all. We know a lot about these particles -- their charges, how they "spin", how they behave.
One thing is odd, though... they all have very different masses*. Photons (what light is made of) don't have mass at all. Electrons have a tiny bit of mass. Quarks can be huuuugely massive (relatively speaking) -- hundreds of thousands of times heavier than the electron. What exactly determines how much those guys weigh??? There are a few "models" that theoretical physicists (the ones who sit around doing tons of really hard math) and research physicists (the ones who build huge machines to smash atoms together) have developed to explain what we know about these particles -- including their masses.
The theory that seems to explain our observations the best, the "Standard Model" (since most physicists think it is true), predicts that in addition to the 12 elementary particles we've directly identified, there is one more -- the Higgs boson. This Standard Model says that all 12 of the elementary particles we've observed are actually massless -- they have NO weight at all, just like photons. Instead, elementary particles that DO have weight get it by interacting with the Higgs boson -- or, specifically, a "field" generated by the Higgs boson. Think of this Higgs field like a thick molasses that permeates the universe, and "sticks" to particles moving through it. Some stick more, some less, some slide through without sticking at all... but the more those particles stick, the "heavier" they seem to us Earthlings, as we study them.
So ANYWAY, this hypothetical Higgs boson makes all the math work out just right, so that the Standard Model very accurately predicts the way we see all of those elementary particles behaving. (In fact, the Standard Model, finalized in the 1970's, actually predicted the existence of particles that we didn't actually see until the last decade or so, once we had built atom-smashers big enough to detect them.) For at least 40 years, the Standard Model has stood the test of time -- so far. There's just one more particle left to find... the Higgs Boson.**
Scientists at the Large Hadron Collider (or its little brother, the Fermilab Tevatron) are hoping to smash atoms together hard enough that the Higgs boson pops out -- probably for less than a "septillionth" of a second. That's NOT very long. But it would be long enough to catch a glimpse of the little guy, and provide even more evidence that the Standard Model is right after all. This has physicists very excited -- in their own words, every time they switch on their atom-smasher, they feel like "a bunch of kids on Christmas morning," ready to rip open the biggest present ever.
(2) "Why is everyone calling it the 'God Particle'?"
The idea is that the Higgs boson is a lot like "God".... We can't see it, but (if it exists) it's literally EVERYWHERE -- all around us, inside us, permeating the universe. It's not that it actually has anything to do with God, or spirituality, or the supernatural, or anything like that -- it's just a catchy name that grabs people's attention (which is why the media -- and the movie "Angels and Demons" -- love it so much).
Although the term is popular in the media, most scientists actually are NOT fans of calling the Higgs boson the God particle... they realize that it grabs people's attention for totally erroneous reasons. (The Public: "WHAT? Science is trying to discover/disprove/explain GOD!??!?" The Media: "Well, no, not really. But we got your attention, eh?") Public controversy aside, most scientists also think the term overstates the importance of the Higgs boson, when really it's just 1 out of the 13 elementary particles. They actually held a re-naming competition to celebrate the 80th birthday of Dr. Peter Higgs (who first proposed the particle). The winning entry was the "Champagne Bottle Particle", which just goes to show you that sometimes scientists are pretty clueless when it comes to thinking up catchy names.
[Speaking of lousy nicknames, my first thought was to refer to it as the Kenobi Particle... ("It surrounds us, and penetrates us; it binds the galaxy together...." -- Obi-wan Kenobi) Some physicists also joke that the term is short for the God-d*** Particle, because of how difficult it is to detect....]
Some people have been making a big deal out of the fact that the Higgs boson "creates mass" or "creates something from nothing".... isn't that God's department??? Does the Higgs boson "disprove" or "explain away" God? Well, no. The Higgs boson doesn't "create" mass... it IS mass (if the Standard Model is right), just like light IS photons. Getting closer to a fundamental understanding of what light (or mass) is doesn't tell us anything about how either of them initially got here (two of the most common options being "spontaneously" and "God created them".)
Rock it, Science! Rock it good!!!
--Travis
* If the term "mass" confuses you, just mentally substitute "weight" in whenever you see mass. They're not exactly the same, but close enough for our purposes.
**As good as the Standard Model is, there are other, competing theories that explain the behavior of the particles that we can see without the need for a Higgs boson. These "Higgsless Models" and the Standard Model make slightly different predictions about what we'd see when we smash atoms together. So, that's one major thing physicists do... set up experiments that would give specific results, results that would match up better with one theory much better than any of the others. Finding the Higgs boson is a perfect example of this.... the Standard Model says we'll find it under specific conditions, the Higgsless Models say we won't. Who's right? Only time (and massive atom-smashers) will tell...