Trying to Understand Relativity (part 8)

In the Principia Mathematica, Issac Newton laid out his revolutionary theory of gravity.  He laid out with incredible precision exactly how gravity worked.  His formulas were used to calculate the exact orbits of the planets with an accuracy that stood for hundreds of years.  Say the word "gravity" and Newton's name is probably the first to come to mind.  His work is a milestone in the history of physics.  But although Newton literally wrote the book on gravity, he left out one little piece of information.  He never made a clear statement of exactly what gravity is.  Sure, he demonstrated how it worked in complex, intricate, mathematical detail, but he never really delved into what it was, beyond the idea that it was a force of attraction between objects that depended on mass and distance.  But what was this force?  How did the sun reach across the millions of miles of empty space and hold the Earth in it's place?  It was like a puppet master moving a puppet, but no one could find the strings.  Newton provided precise calculations of how the puppet master's hands control the puppet, and he basically left it to someone else to figure out the nature of the strings.

The someone else was Albert Einstein.  With his theory of General Relativity, Einstein showed that gravity was caused by the fabric of space-time being warped by the mass of an object.  The heavier the mass of an object the bigger and deeper the warp it caused in the fabric.  Imagine you have a blanket stretched out tight in the air.  If someone sets a baseball on it, it causes a dip around it in the blanket.  If someone sets a bowling ball on it, it causes a wider, deeper dip.  If you bring the baseball close enough to the bowling ball, it will fall into the bowling ball's dip and hit it.  This is what causes gravity.  This concept corresponds exactly with Newton's calculations of his "force" which varied according to mass and distance, but in a way he probably never imagined.

After spending the past month discussing time and time travel, it's got me wondering if there isn't a point at which Einstein's theory runs up against the same sort of wall that Newton did.  In case you missed it, I added a rather long edit to the last relativity post.  It starts about halfway down with the word "EDIT".  If you're actually making a serious attempt to follow this mess, then I suggest going back and looking it over.  I start with an explanation of the concept of relative motion, and then the constancy of the speed of light, and then I get into a thought experiment demonstrating how the time distortion effect can be inferred from these facts.  It's a rudimentary explanation of Special Relativity, and it's about as far as I've gotten at this point.  

Now, I'm told that I need to bring General Relativity into the picture to solve our Bob and Ann problem, but I'm not quite done with Special Relativity.  For one thing, I feel like I've barely got a finger hold on the idea.  I certainly don't feel confident that I have my mind completely wrapped around it, and I'm not ready to move on just yet.  But something else bothers me as well.  I kind of get how you look at the constant speed of light and you're forced to draw the conclusion that time distorts to compensate, but I'm not quite sure what this tells us about the nature of time.  This is where I feel like Relativity begins to run into that Newtonian wall.  Maybe it's my own limited understanding.  I spent some time yesterday, looking up "space-time" and "Minkowski space" and found a lot of equations that might as well have been written in ancient Sanskrit, for all that I was able to understand them.  But yet, I couldn't quite find what I was looking for.

I get the sense that Relativity looks at relative velocity and the constant speed of light, and then simply demonstrates the mathematical fact of time dilation, in the same way Newtonian physics looks at mass, motion, and attraction and then demonstrates the mathematical fact of gravity.  It's like, you point to where they show up in the calculations, but you're not really explaining them beyond the math.  Perhaps I'm being presumptuous.  Maybe the answer has just gone completely over my head.  Still, I can't help but wonder:  What is the significance of the fact that time can be distorted?  Why are mass and velocity the defining factors in this distortion?  What does this tell us about the nature of time?  Suppose time is the "dynamic flux", the constant change and motion of all matter in the universe that I proposed earlier.  Then, what does it mean that an observer can see this flux slow at high velocity?  If anyone has any answers, feel free to speak up.

It's like "dark matter", which is a theoretical construct that scientists use to make the calculations work in astrophysics.  They really have no idea what it is.  It's just something that shows up in the calculations.  Or consider the puzzling results of the double slit experiment that show up in quantum physics.  There is an old fable about three blind men stumbling across an elephant.  One of them grabs the trunk, and declares that the elephant is like a long snake.  Another grabs the leg, and declares that the elephant is like a thick tree trunk.  Still another feels the side of the animal, and declares that the elephant is like a wall.  I get the sense that these scientists are like these blind men.  There's something there.  It reveals its presence in the equations, but what it is remains a mystery, seen through a formula darkly.  I don't mean this to be derogatory to scientists, by the way.  They'd be the first to admit to being mystified.

The philosopher Immanuel Kant proposed that time and space were simply products of the mind, concepts that we filter reality through to make sense of it.  Frankly, I've always been appalled by this idea.  If time and space aren't objectively "real", then how can we hope to establish any sort of solid reality beyond ourselves?  The slightest flirtation with this idea and it feels as though the vast universe is about to collapse into my brain and become some sort of flat non-entity, like an image on paper with no depth.  It's likely that my understanding of Kant is as flawed as my understanding of Einstein.  But this idea that the speed of time's passing is relative to the speed of the observer forces me to at least consider if there isn't an element of perception involved in the nature of time.

And on that confusing note, I bring my contribution to "Time Travel Month" to an end.  I hope you've all had fun.  I enjoyed it, but I feel like I could go another ten years without talking about time travel and its strange paradoxes again.  It's been a little exhausting.  Oh...And hey, Doug, if you followed the link here from the first post of the month and you're reading this on February 1st, don't forget to mention something about the timetravelfund.com in the comments below that first post.  I don't want to waste any time getting on the ground floor of that amazing opportunity.  I'll thank you for it later.

(This post also available in extra cheesy version.)