I should have been clearer - the bulk of 'stuff' is dark energy, so while dark matter is what everyone says dark energy is the dominant factor. I goofed that one pretty severely. The other issue is that when you go too far into the stuff you basically set a few fundamental constants equal to 1 to simplify the math, and then you can't tell anything from anything else - distance and time, mass and energy, blah-dee-dah, and so on all get lumped together because noone wants to write 'c' and 'h-bar' that many times.
yeah, sorry, it's quite difficult to explain what's on my mind. All I wanted to say is when using the word "matter" things get tricky, the word sort of implies something more or less tangible.
Things are still pretty tangible, just not for the reasons you thought. I think I know roughly where you're getting nervous about the stuff, and it's somewhere after 'stuff you pick up if you learn a little physics' and before 'stuff that clarifies the typically lousy misconceptions after you've learned a lot of physics'.
When entering the quantum world, the ways we intuitively perceive our reality become useless...
And that makes matter intangible? We should be able to accept 'well, the classical framework doesn't work everywhere' without throwing out stuff altogether. Dealing with quantum mechanics isn't as mysterious and magical as the funny-haired people on television make it out to be, it just requires some math.
Even if you toss out the idea that particles are The One True Physics Thing, you still basically recover the same physics - fields (which a lot of people think of only as 'the stuff in between things') are the things you work with in quantum field theory, string theory has strings, et cetera, but we still have matter basically falling out of the equations one way or another.
Explaining mass is a bit tricky, but that keeps being improved (Thanks, ridiculously-expensive and complicated particle accelerators built wholly on lies, deceit, and an international conspiracy to suppress outside opinions!) and generally things aren't as hopeless and confusing as they seem. (Caveat: again, math. You need math. Lots and lots of math, it seems at first, but actually it's not too horrible.)
... so there might be a whole lot of "something" out there, but it's not some big black blob flying around that we might associate with the word matter in it's intuitive "tangible" meaning.
This is skirting around the main point - it doesn't interact with light (and therefore not with the electromagnetic force, as that's mediated by photons), so the only thing we can observe it doing is screwing with things that have mass.
Acctualy I think i'm trying to explain it to myslef, so be patient
That can be a key part of figuring things out, but do the math before you settle too quickly on one idea... especially with anything involving quantum mechanics, where the way we handle things is still largely analogous to a method for approaching problems in classical mechanics.
(Of course, that method is the difficult one that you don't see until you go too far in for your own good - because anything else would be silly, obviously - and a lot of physicists seem to neglect the math behind the 'translation'... so explaining the basics without 'Wooooo: stuff is actually wibbley bits of not-quite-stuff, except when it's not, and mysterious quantum boobledeegooble' can be a bit tricky. And then of course you get non-physicists who don't get it trying to explain it, and that's a whole different mess altogether...)
Seriously Jeff et. al. it's a lost cause, he's never gonna bother to do enough work to get the first clue.
I'm actually curious to see how much work it could take to take a nonsense thread and derail it onto a useful course. (It's also nice to finally see someone worse at physics than the people I deal with in the real world, and respond as I would to them if I weren't supposed to follow stupid things like 'codes of conduct'... and 'proportional response'... and the Geneva Convention...)
Jef
