Empty 4/5/22

Science with Richard Bleil

Suppose just for a moment, it were possible to expand sub-atomic particles.  Take, for example, a simple hydrogen atom which consists of one proton, one electron, and no neutrons.  If we could expand the size of the proton so that it was the size of a basketball, then the electron would be about the size of a golf ball.  The question then becomes how far away would that golf ball be?

I used to ask this question to introduce students to chemistry when I lectured.  I would ask, would it be in the auditorium?  Or in the science building?  How about on campus?  Of course, students had no clue, and I didn’t expect them to.  My desire was to activate their imagination on the topic, although my success in doing so is a subject for debate.

As it turns out, the golf ball would be roughly five and a half miles away.  Yes, I meant miles.  About the distance to my favorite pizza joint in town.  And in between the electron and the proton?  A vacuum?  No, not really.  The concept of the vacuum doesn’t really apply to a distance so small in reality.  A vacuum would try to draw gases out of a volume (that is to say, in the presence of an adjacent vacuum, the intermolecular repulsive forces between gas atoms and molecules would push them, rapidly, violently and unopposed into the vacuum).  There can be no gasses in the space between the proton and electron because that space is smaller than other molecules can fit.  What is actually there is the subject of this post.

The subject of this great distance has been the stuff of science fiction for a long time.  I can think of at least three science fiction plots that have centered around it.  The first one I saw was in the old black and white Superman television series from the ‘50’s.  The plot of the episode involved a criminal who encased himself in a lead-lined box so strong that even Superman couldn’t break through it.  A physicist convinced him that, if anybody could do it, only Superman would have the mental power to align his own atoms and molecules so the space between the nuclei and electrons would align allowing him to pass through the wall as if it wasn’t even there. 

Interesting how any far-out scheme that is always nearly impossible always seems to work out in science fiction.

Well of COURSE it worked, right?  Why wouldn’t it?  Except that empty space isn’t really empty space.  What is DOES have are the forces that keep the protons and electrons near each other.  It is, in essence, a force field.  Currently the only force we believe exists there is electrostatic, akin to magnetism.  The nucleus of any atom is positively charged (how large the positive charge is depends on the number of protons in the nucleus which identifies the specific element the atom belongs to), and electrons are negatively charged.  There is an attraction between the electrons and the nucleus keeping them close, but the electrons repel each other preventing them from colliding with the nucleus in a delicate ballet of motion and energy.  If you want to align your subatomic particles so the nuclei or electrons of your molecules pass between those of another, you would find that you are trying to pass charged particles through an electrostatic field, one that would draw your subatomic species to either collide with or be repelled by those you are trying to pass it through. 

The reality is that you could never get that close.  See, electrons aren’t really particles anyway.  Modern chemistry textbooks, presumably written by educated chemists, drive me crazy because they try to explain “spin” by representing electrons as a sphere on an axis, rotating clockwise or counterclockwise.  The truth is that Heisenberg, whose principle is the bedrock of quantum theory, tells us that we cannot know what an electron actually is anyway.  Early experiments on electrons after their discovery confused scientists, because they behaved like a particle in some experiments, and a wave in others.  That they couldn’t pin down if electrons were waves or particles was another example of how classical Newtonian physics actually fails on the subatomic scale.

In fact, electrons are more like clouds.  They move so fast, act like waves, and are impossible for us to really understand.  The best we can do is predict where they are most likely to be found, regions in space we call “orbitals” which are just regions of space where electrons are most likely to spend their time.  These orbitals surround the nucleus, and the cloud of electrons lives mostly around that nucleus.  When we touch something, what we are actually feeling is the electrostatic repulsion of our negatively charged electrons from the negatively charged electrons on the surface that we are touching.  In these (almost always cheesy) science fiction story lines, the problem is not fitting subatomic particles between one another, but rather, overcoming the electrostatic repulsion of the electrons that surround every atom.


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