3D Musings

I was listening to a news blurb about 3D Televisions recently, and I began musing about the three dimensional world.  Most of us have a general understanding of dimensions from high school geometry.  Zero dimension is a point, one dimension is a line, two dimensions constitute a plane, and three dimensions has depth x, y, z if you are using a Cartesian coordinate system. 

If I asked you how many dimensions we live in, you might say 3 or maybe 4 if you want to be spry.  Perhaps you are a follower of string theory, wherefore you will give some unbelievable number. As stated on Season 1, Episode 1 of  The Big Bang Theory

Leonard: At least I didn’t have to invent 26 dimensions just to make the math come out.
Sheldon: I didn’t have to invent them. They’re there.
Leonard: In what universe?
Sheldon: In all of them. That’s the point.

Technically we live in a 3D world. Though, I am starting to think we are in a 3D world but confined to a primarily 2D plane that happens to have topography.  Yes the Earth is roughly a sphere, but human experience is basically a plane.  Regarding the other type of planes, we do go up-and down, but we always return to our pseudo-3D existence. This lead me to muse (hence the title of this post) about what things actually experience true three dimensions.

Minute Physics tells us how we know one of them.

But that is about it. Molecules will expand in 3D by diffusion. I am not sure where limit lies.  There must be some relationship between size and mass of an object for when it falls prey to the effects of gravity. Perhaps astronauts can fall into this category also, free motion in any of the space around them. Those of us who are earth-bound are gravitationally confined to this flat life.  Our cells are attached to us.  The enzymes and organelles in our cells are confined by microtubules. It is the molecules that swirl and spin and flitter about that get to experience three dimensions. 

It is one of the great challenges of chemists and chemistry students to be able to think of structures devoid of dimensional limitations.  We think in this pseudo-3D fashion and often are constrained to a 2D piece of paper for exams and notes.  Computer modelling has been a big advancement in helping to understand this 3D nature of molecules. 

Here is a model of the simple sugar glucose.  Imagine all the ways you could draw this in 2D when rotating it in 3D!

Many people are working on showing how molecules interact in 3D as a method for finding new drugs and understanding life processes. Here is a video I found on YouTube of a drug binding with a protein.  I couldn't find a reference to tell you more about it, but it is a good depiction of what pharmaceutical companies and scientists are now doing to understand the minutest interactions within the body.

Long before we had this understanding, Albert Einstein thought about this problem.  I don't know what his particular thought experiment was specifically.  In my words, he observed that small particles that should be confined to our pseudo-3D world like dust and pollen would move.  This suggested there were even smaller particles out there interacting with them.  Again, I will turn to Minute Physics to demonstrate.

So, as you go for a walk, climb a tree, or take a flight this month, think about the fact that you are living in a limited three dimensional world.  Even the lightest snowflake must fall to the ground.

If I had you convinced that molecules have it easy, remember that even they (except maybe helium) are confined to our atmosphere and don't get to just float off into space. So much for 3D.  Maybe that is why we dream of 26 dimensions.

One final note, here are how 3D TVs work!

http://www.popsci.com/gadgets/article/2010-01/its-about-time-3-d-comes-home

http://www.wired.com/gadgetlab/2009/10/3d-tv-explainer/