After viewing If the moon were only one pixel, the tediously accurate scale model of the solar system, I was immediately captivated by the point the author was making.   That point is that there is a lot of emptiness in space.

There is nothing new about this.  Obviously the planets are far apart and separated by empty space.  It was one of the earliest things learned as a child.   It becomes more inescapable after learning geometry that says a sphere of a radius matching the distance between the sun and the planet will compute to a huge volume that contains virtually nothing.    Volume is a property for the abstract geometric concept of the sphere.  The fact that the volume is empty never challenged my understanding of the concept of the volume.

But in the above link, I deliberately scrolled through the the scale model and experienced the nothingness.  Usually a solar system model emphasizes the planets.  The planets define the solar system at least in terms of what we can see.  But this model draws attention to the emptiness of space.  Scrolling one screen at a time, it is all featureless and black (occasionally broken up by some statement).  Even the screens depicting the scaled planets were mostly black emptiness.

I actually found myself fascinated by the dynamics of the scrolling and mentally trying assemble the different planets into a single concept.  At this scale, it takes real effort to comprehend the concept of a solar system.   At the same time, scrolling through screens of emptiness seemed to challenge me to pay attention to that emptiness.   What is does empty mean, and why is there so much of it.

A volume defined by a sphere that happens to contain a few specks of planets is obviously mostly empty.   But the more I think about it, the more mysterious the concept of emptiness really is.

What if emptiness is an illusion.  What if emptiness is not reality?   The concept of area or volume is an abstract geometric concept.  It happens to be very practical for estimation material that fills a particular area and volume.   Both area and volume are defined by a distance.   Any abstract figure of certain dimensions has a predictable area or volume.  If that volume actually contains nothing, then it is empty.  

We extrapolate from experience on earth where we have containers and can measure how much stuff it holds. If the container is empty then it can accept a predicable amount of stuff.  But in our experience it is never empty, it is instead filled with air.  Putting stuff into a container merely displaces the air that previously occupied that volume.   We can make vacuum chambers that can come close to the emptiness of outer space, but this is constrained by a substantial container.  The volume is empty because it has the potential of being filled.

Outer space has no potential of ever being filled.  For some reason, this seems to be a different kind of emptiness.

The emptiness of space may be an illusion.  We can measure the distance to planets.  From that distance we can calculate a volume.  That volume is concept.  That concept of a volume happens to contain nothing.

We can travel through space in a space ship with an internal air pressure.  We infer our travel by knowing our speed and by recognizing how long it takes to get to our destination.  We know that in the middle of this travel, if a leak were to occur the inside air would irretrievably leak into an exterior that has no air.   It is obvious that we are traveling through a volume that happens to be empty.

But as I think about it, it doesn’t seem obvious any more.  On earth, we know we are traveling because we are traveling through material.  If walking we tread on a surface that changes and brings us closer to our destination.  We can feel the air we are traveling through.   It is natural to project this experience to space travel with the exception that there is no material to travel though.

Space travel is purely traveling over a distance.  It is not covering ground.  It is moving along a distance that can be measured.   After an initial short acceleration the ship is in constant speed, and inertial frame.  Distance is a consequence of moving for a specific amount of time at a certain speed with respect to another object.    We project our earthly experience to the situation to say we are moving through something and that something is emptiness.   But this is just an illusion.  We are passing time in a point of reference that is moving at a certain velocity.   Admittedly the ship’s success depends on maintaining the integrity of its structure separating the livable environment from what is outside of the ship.   But that is a locally meaningful fact.  All of the rest of the volume of space is suspect as an illusion.

There is no practical advantage to my suspicions and plenty of impractical implications to even question it.  My only point is when I contemplate the emptiness that surrounds us, I am somehow awestruck.   Not only the emptiness around us, but the emptiness inside us.  Most of the volume of physical bodies is empty space.  Atoms are mostly empty space.   A good approximation of anything is that it is perfectly empty.

Where did emptiness come from?   I think of the concept of the big bang or the one I understand as at some point suddenly there was something.   It was a bang, a flash of light where there was only darkness before.  Maybe I have it backwards.  Maybe there was a stable everything all squeezed into a zero-dimensional point.  This couldn’t really be considered bright because there is place for light to move, but it is something that contains everything, everything except nothing.

Perhaps what happened was not so much of an explosion, but instead the introduction of the 3 spatial dimensions (perhaps one at a time).   Instead of a “let there be light” kind of event, it was a “let there be emptiness” event.  The big bang didn’t create the universe, it created the emptiness.

Is there a purpose for emptiness?