SmurfButcher Bob's Journal: SpaceTime?

Regarding space being a 3D thing or not - it's all about perception, and perception is why it's such a challenge.

Consider something, a game merely provided as a thought experiment.

Consider a creature who lives in a 2D world... that is, his perception is limited to exactly one single plane that is infinitely thin. Grab a stiff sheet of paper, neglect friction, and pretend it has no thickness. We're going to try to see what our creature sees, the same way he sees it, and eventually see how it scales as "dimensional perception" increases.

Take a round pen, and "intersect" the middle of it with our plane. ----|-----
Our creature will perceive the pen as a circular wall... remember, he has no concept of "up" and "down". Easy.

Spin the pen in various directions, and note what happens - and remember, we're only interested in that infinitely thin section that our creature can perceive. You can produce spin 0 (if the pen is a cyllander), spin 1, spin 1/2, spin 2... you can create all types of "spin" based on the direction you rotate it. Interesting. Note that this is not necessarily the same "spin" that the quark-heads talk about, but it demonstrates a fair part of the concept. It certainly demonstrates the concept of things "coming into view", and will probably make our poor creature pull his hair out. It's especially interesting because our creature sees the pen changing - shape, size, you name it - but you and I know that the damned pen isn't changing one bit.

Now for a really neat demo - tilt the pen, and hold it still. ------/-----
Without rotating the pen, move it straight up or down. What's our creature going to perceive? Yep... he'll see the "pen" (the big circular wall, which is now an oval due to the tilt) moving across his plane. That's neat, and a good concept demonstrator - but it isn't the really cool part. The really cool part is that he'll see the pen moving along the X-Y plane- despite the reality that it's really moving along the (unperceived) Z axis. You can see that the pen has no horizontal motion whatsoever - yet, horizontal motion is exactly (and only) what he perceives. Take a second to reenforce why he perceives it that way, and make the reasons work. Remember, we don't care what his perception is, there is no horizontal motion in reality. The motion is all in the unperceived vertical. Period. The only thing changing (not moving, but changing) is the point of intersection with his ability to perceive, the cross-section within his perception.

Finally, grab a more complex object. Something fun - a coffee mug perhaps, or a fork, or even a pair of scissors. I'll use scissors, because I enjoy cutting things... and when we're done, we can use them to wreck havoc on our creature's universe.

Open the scissors up a little, and hold them below the sheet of paper. What's our creature going to perceive? Nothing.

Now, lift the scissors and stick the points into our creature's plane of perception.
-\/-----
OO
Our creature will perceive the scissors as intially one, then two completely separate objects as the points come into view, right? And what else... they will appear to spontaneously exist. Of course, you know that the scissors have always been there, just not within the creature's view.

Things get interesting, though - if our creature decides to kick one of those objects, he'll notice that the other object moves a little. It'll make no sense to him - the two objects have nothing to do with each other, yet they almost seem to be... I dunno... entangled somehow. (And no, I'm not suggesting that this is how entanglement or pair production works, this is just a method of showing how a limited perception can create the illusion of such a thing.)

Move the scissors up, and notice that our creature would see the two objects moving toward each other, and also get bigger (as each blade gets thicker). Keep moving up, and our creature will be astonished when they actually merge (at the hinge-point). Keep moving up more, and more, and the creature will become baffled as the merged object suddenly breaks back into two separate pieces, moving away from each other. Move it up some more, to the handles and beyond, and our creature will see the two chunks break into four (when the handles are intersecting) then back to two (and the end of the handles), then suddenly shrink away to nothing!

Wash, rinse and repeat the game with something incredibly complex, like a lawnmower. Our poor creature is going to need a good stiff drink after trying to explain this one to his friends, I tell ya...

The one very cool thing about this entire game (and it is merely a game, it is not reality by any stretch) is that we've beaten the 2D perception of a 3D object to death, so we can see how it scales up. What we can do now is repeat the game, using a 4D object - namely, let's introduce what we perceive to be time into our game. Do this any way you like - open and close the scissors, spin them as you move them up and down, let them rust, whatever. You will rapidly discover that our (now hopelessly confused) creature cannot differentiate the 3D game from 4... he won't be able to tell how many dimensions we're throwing at him. He'll perceive them all as one single "dimension" that he calls "time". Think about when we played the game the first time - what we call Z in our perception, would be "time" in his, right? We then replay the game with both our Z and our time, it's still just "time" in his. He cannot tell if there is only one unperceived dimension, or one hundred... these extra vectors are all summed together into one, for him.

Now, stick your head out the nearest window, and watch a car drive by. You should be able to see it in a whole new way - as if you were some poor (hopefully drunk, by now) creature, perceiving a shifting 3D cross-section of a god-knows-how-many dimensional *static* object. There's still motion, for sure - but it isn't necessarily the object that's "moving", is it :) The thing that's actually moving just might be the point of intersection between our... uh, perspective-space and the object, and the "object's motion" is merely a side-effect of us only seeing a limited cross-section of a larger-dimensional solid.

I'm not suggesting that this is the case, but suddenly a photon spontaneously changing into an electron/selectron pair that move away from each other suddenly takes on a whole new... view. Or, the right-hand-rule - an electron following a helical path in an E-field? What if we took our pen, and made it wobble as it moved along? Fun games, regardless of how wrong they are.

It's all about perception, or lack thereof.