science is cool...
"Consider, for a moment, the chair your butt is resting on right now. It's made of a squillion atoms right? And since it's a solid, all those chair atoms are packed tightly together like a vast collection of marbles in a box, right? And it's all those tightly packed atoms/marbles that are holding your butt in the chair against the force of gravity, right?
Well, actually, no. There is a tiny problem with the whole atoms-as-marbles picture.
It's entirely wrong.
Every atom has two components. There's the nucleus at the center (made of protons and neutrons) and then there's a bunch of electrons whizzing around the nucleus. When you see a picture of this, it usually looks like the nucleus is its own bunch of tightly packed marbles and the electrons are orbiting a little ways out.
The atom you see in high school textbooks, really, is not an atom.
But here's the problem with that kind of picture. You see the nucleus is only a few femtometers wide. And what's a femtometer you ask? It's a thousand million millionth of a meter, which is so incomprehensibly small to try to imagine it can blow a fuse in your imagination. But imagining such a tiny sliver of tinyness is not the real problem. The real problem is understanding where the electrons are relative to the size of the nucleus.
The average distance of an electron from the nucleus is about a ten-billionth of a meter (or what we in the biz call a tenth of a nanometer). So the nucleus is a femtometer across, and the electron is a tenth of a nanometer from the nucleus. What's the big deal? Just this: A ten-billionth of a meter is a hundred thousand times BIGGER than a femtometer. That means the electrons are a hundred thousand times farther from the nucleus than the nucleus's own width. If the nucleus were a beach ball in Midtown Manhattan, the electron would be living in an apartment in Philly.
And what does that mean? The atoms making up your chair — you know the ones supporting your booty right now — they are pretty much all empty space. Each one is a vast stretch of nothing that is lightly salted with an occasional fleck of stuff wandering in an endless void. And, as atoms go, so goes your chair — it's just empty space, too. That image you had of solid matter as tightly packed marbles? Nope. Not even close.
But now comes the $64,000 question — if atoms are nothing but deserts of empty space, how does your butt even know the chair is there? Why don't the flecks of butt-matter in the endless void just pass right through the flecks of chair-matter in their endless void?
The answer is as simple as it is weird. It's all just forces.
Cracking like lightning through the void, all the specks of electrons and the specks of nuclei are constantly interacting through a force called electromagnetism. Each interaction is carried out through the jolting exchange of particles of pure energy called photons (which is really just a nubbins of light). Each photon swapped equals a little push or a pull — a force — exerted across the emptiness. That's really what's keeping the stuff we call your butt from drifting through the stuff we call your chair.
So, the truth of the matter, dear friends, is there is no "solid" matter. Everything you think of as solid — tables, chairs, a '69 cherry red Ford Mustang, your child's noggin — none of it is really solid. Instead, there are only rapid-fire bursts of pure energy carrying forces between impossibly small flecks of somethingness. And all of it is lost in an atomic void as empty as intergalactic space."YES! That what I was getting to with Gopal about physical matter and the forces that bond atoms which are predominantly empty space. It's purddy whacky stuff to even contemplate.