(NOTE - If you are just coming to this blog, this is the end. The beginning is on page 2. Scroll down to the bottom of this page and start on page 2. Then come back to page 1 and read up from the bottom.)
One thing I didn’t mention is the possibility that the flow of time doesn’t really exist other than in our minds.
I noted earlier that Special Relativity can be interpreted this way, and General Relativity doesn’t distinguish a separate time dimension, just four equivalent dimensions of space-time.
Time, particularly the flow of time in one direction only, is allowed but not required by the physics.
So time could be another part of our three-dimensions-in-four illusion.
In this view, the universe is static, without time, and what we call the past and the future exists all at once. We just don’t experience it all at once, but little bits at a time. It’s like a film that exists in its entirety on a DVD but we experience it by reading the DVD from the beginning to the end. It wouldn’t mean anything, or even really exist, if we could see it all at once, which we can’t.
There are a lot of considerations as to how this universe might work, but ultimately the conclusion is the same: we don’t know. Any type of existence that doesn’t involve time we can’t understand. Some say we can access it directly without thought. Maybe. But that isn’t understanding.
It’s a mistake to confuse understanding with direct knowledge. And it can be very, very destructive.
More to come…
“Momentum spontaneously begins out of null-where/null-when/null-thing, and the universe exists because not existing is an unstable condition and isn’t allowed by the laws of physics.”
Here is a list of the words and phrases in that sentence that involve time—that depend on a temporal experience in order to have meaning.
The laws of physics
We are left with “null-where/null-when/null-thing”, and just naming that unthinkable concept has a context, and context is temporal, so it’s ringed in by time. Just by thinking of it, it becomes effectively a temporal concept.
It’s like the relationship of an event horizon to its black hole. What’s in the black hole is forever unknowable to us, and us to it, but the actions at its surface give it a unique physical presence in our universe. Thinking about "The Null" is temporal.
We cannot think or know anything outside of time. And non-existence of the universe is outside of time. Saint Augustine devotes about three pages of the Confessions to time and what lies outside of time, which he calls eternity. You should look it up. I don’t think we know any more today than what he said fifteen hundred years ago. His famous concluding quote is “What then is time? If no one asks me, I know what it is. If I wish to explain it to him who asks, I do not know.”
So suddenly, I’m talking about time. I started with dimensions and space, and then motion, and spent all that time (ouch!) on momentum. What gives? Is time the fundamental problem?
Remember, I defined time as motion. Motion requires mass and space because something has to move and it has to have somewhere to go. Mass doesn’t exist without motion. And motion requires time. It’s all circular. Momentum is the concept that combines all four: time, mass, motion, and space.
It doesn’t matter where I start, or which one I focus on. Talking about any one of them implies all of them, implies momentum. The wholeness of the concept of momentum is what is fundamental.
So where does momentum come from?
This is where I end: We do not know and we cannot know.
Physicists can devise models that fit our observations, and we can extrapolate into the past (sort of) and define a "time" at which everything began, but philosophically it's a dead end. Momentum can't begin without time, or space, or mass, or motion. Momentum can't begin without momentum.
It’s not because we don’t have enough information or because we aren’t smart enough. We don’t know because the question we are asking is meaningless. As Stephen Hawking commented about a similar question, it’s like asking what’s north of the North Pole. Northness ends at the North Pole because everything is south from there, not because we need more information.
I know this can seem over simplistic, and I'm open to being convinced otherwise, but the concept of anything existing with time and nothing else, waiting eons for the moment that null momentum turns into plus momentum and minus momentum equals zero momentum, just seems to me to be shot through and through with our human temporal prejudice. I don't buy it. Momentum and time are one. The whole ball of wax or nothing.
So what’s the point of all this?
Per Plato again, knowing that I don’t know and can’t know means I know more than I did before...and more than most.
Note that this discussion is all about understanding, which is a particular type of knowledge. It's thinking knowledge. There are other types of knowledge that don’t ask or answer in the same way at all. We use them all the time without thinking. They help us when understanding fails. They also lead us into some of the most destructive and unwanted actions of which our species is so sadly guilty.
Why? I think it’s because we carelessly mix unthinking knowledge and thinking knowledge in unproductive ways. But…that’s for another time.
I’m still looking for the origin of momentum.
The universe is a zero sum game with momentum. All the local momentums add up to zero.
So it’s easy to see that as with light, from the point of view of the universe as a whole, nothing has overall been lost or gained overall by the creation of momentum.
However, unlike light, which is without mass, time, space, or motion (from its point of view), the universe has gained all four: mass, time, space and motion, the components of momentum.
This really matters to us. I mentioned earlier the Platonic principle that no part of a whole can perceive the whole. In order to do that, the part would have to be outside the whole, and then it wouldn’t be part of it. And the whole wouldn’t actually be the whole if something could be outside it.
We don’t care that what we see adds up to zero, because what we see are parts, and parts are definitely NOT zero.
But where did it start? Why are there parts at all? Where did momentum, the stuff of the universe, begin?
The Heisenberg Uncertainty Principle of Quantum Mechanics has an interpretation that offers an explanation that appeals to some theorists. Heisenberg discovered that there are pairs of attributes in the universe that have the unusual relationship that both cannot exist precisely together. One of these pairs is the qualities of momentum and position. A mass cannot have a precise position and a precise momentum at the same time. The relationship is even more troubled than that. If one is determined precisely, the other becomes undefined. It both doesn’t exist and it exists in all possible ways.
I need to make sure I’m clear here. This isn’t just a measurement problem in the normal sense, though that is involved. It’s not that the two really have precise values at the same time, we just don’t know them. They really can’t exist precisely together. As long as we know both only approximately, both exist—approximately. In our large scale inexact world, we can only know things approximately anyway, so we don’t have a problem.
So the argument for the origin of momentum says (roughly) that since 0 momentum and 0 position are exact quantities, that’s not a possible state. In other words, not existing is not allowed. And of course once one of these exists approximately the other also exists approximately, AND the momentum created has to come in pairs that cancel each other out, so the total momentum of the universe is always zero. (Note that the Uncertainty Principle functionally applies only to tiny individual masses, not to larger congregates, which is all we deal with on a daily basis.)
Physicists use this idea in our existing universe to explain some really arcane, but fundamental behaviors in the universe. Because of the uncertainty principle, it’s proposed that “empty” space is actually a boiling mass of particles being created and annihilated constantly at energy levels and in time spans so small that they never break through the threshold of Uncertainty Principle approximations into our observable universe. For QM physicists, this has to be true. It’s required by the science, and assuming it is true makes explaining some things easier, but of course, by definition, it can’t be observed.
So is that the answer? Momentum spontaneously begins out of null-where/null-when/null-thing, and the universe exists because not existing is an unstable condition and isn’t allowed by the laws of physics?
Physicists are rolling their eyes now at the gross oversimplification of that conjecture, but still, we have to start somewhere philosophically. One more blog!
Our perception of light says at least as much about us as it does about light.
We perceive light behaving the way it does because of what and where we are while perceiving it.
I am going to make the assumption that light actually exists. This is not a radical assumption on the face of it, but I have just stated that from the point of view of light itself--which ought to be an important point of view--light doesn’t exist, never has existed, never will exist, and doesn’t/neverhas/neverwill even have a universe to exist in.
Something is wrong with my understanding of existence.
Existence requires space, time, mass, and motion. In a word, existence requires momentum.
Let’s back up, way back, to a point of view that is impossible, but, for simple purposes, can be modeled. Let’s look at the universe as a whole.
What is the total momentum of the universe?
It’s a closed system. Its total momentum is zero. For every part moving one direction there is an equal part moving the opposite direction that cancels out the overall momentum.
This would indicate the universe doesn’t exist.
Assuming that it does, the problem is clear. Existence depends on local characteristics. It’s local momentum that matters. As long as our corner and all the other corners of the universe have measurable momentum, we’re all real, even if we all add up to nothing.
How can this help us with light? Does light have parts?
The wave theory helps again. Yes, there are parts. Light is made of alternating electric and magnetic fields. And they don’t move at the speed of light. As one field grows, the other decays. The field that grows begins to create the next field and then decays as the new one grows. It’s the front edge of this constantly self-creating, self-destroying pair of fields that moves at the speed of light. The fields themselves, like the waving flag on the flagpole, don’t really move in the direction of travel of the light.
The momentum of the light beam lies in the energy of these fields. When light hits something other than a vacuum, these fields give up some or all of their energy to whatever that something is. But the particular fields that hit that something are NOT the fields that started the light beam. Those never went anywhere at any speed. The final fields are created shortly (very shortly!) before the impact and all they do is try to transfer their energy to another set of fields but something in the way prevents the next set from being created. Their energy has to go somewhere, so it goes into the something in whatever form that something is structured to handle, but it’s no longer light. And, though the energy was transported at light speed, no mass actually moved from the beginning point to the ending point.
The alternating E and B (B for magnetic…I know, just accept it) fields do move. They oscillate at right angles to the direction of travel of the light they create. Just like the waving flag moves back and forth but not at all in the direction of the waves in it.
The difference again with light is that there is no flag. Light propagates in a vacuum. And it propagates in all directions. This is because there is nothing keeping the two alternating fields in one plane, so they go all over the place in every existing dimension. The rate of dissipation (in a vacuum) would be 1/r^2 in three dimensions, 1/r^3 in four dimensions, etc.
Since we observe a dissipation of 1/r^2, we can conclude that light and we exist in three spacial dimensions and one of time as we perceive light. This jives with Relativity theory and seems to answer out initial question about dimensions. The extra ones proposed in current physical models would be so small as to not be able to be detected, non-zero, but small. They would have noticeable magnitudes only under extreme conditions, like the birth of the universe.
Our perception of light says that we are three dimensional, lower than light speed creatures in a four dimensional, light speed defined universe. Light is the lines and boundaries of the universe. It shows us how the universe is shaped. Remember, when a light beam bends near massive objects, it isn’t being bent at all. That’s just how the universe is shaped. It has curves in it—sort of like a straight road in West Texas (and that’s straight!) that actually bends slightly around the curvature of the earth.
I’m getting close to the end of this line of thought. Just a couple more blogs.
And still, where does momentum come from? Oh, yes there’s that thing, Quantum Mechanics. Could that help?
From the point of view of Special Relativity, time doesn’t flow. It’s just another dimension that for reasons we don’t understand we perceive in only a limited way and in only one direction. The order of occurrence for events that are relatively close in time can change depending on the position and relative motion of the observer.
In General Relativity, the four dimensions are called space-time dimensions and are not theoretically distinguished, although a common formulation of the equations can separate them.
A possible implication is that the future exists just as concretely as the past does.
---ANOTHER NOTE – General Relativity is probably not a complete theory. Quantum Mechanics is not yet reconciled with it and the evidence of what is called dark matter or dark energy is opening new questions. This means that the foundations for these philosophical interpretations are not really secure. However, we should be willing to work with what we have and see where it takes us, while being ready to adapt to new information. --
It seems clear that light occupies a special place in the physics of our universe. It is a constant of a sort. The speed of light is constant in all inertial reference frames and locally constant in all reference frames. (“Inertial” means not accelerating.)
When talking about light earlier I spoke of it as a particle. It’s also thought of as a wave. When Maxwell devised his electromagnetic field equations 150 years ago, it was all about waves.
Waves in and of themselves are interesting things. They move without anything actually moving much in the direction of the wave. Think of a long thin flag rippling in the wind. The waving cloth clearly has a motion from the flagpole to the tip of the flag, but the flag itself is equally obviously going nowhere, just moving side to side in a regular pattern to create the moving waves.
Electromagnetic waves, which light turns out to be, have another oddity. They wave without anything there to wave. No flag. And they dampen rather quickly compared to a flag because they spread out in all directions through space, which, of course, they do at the speed of light.
The wave theory of light is very attractive because it has the speed of light built into it. That’s one of the most remarkable results in the history of physics. Light speed has to do with the rate of propagation of the intertwined electric and magnetic fields as they alternately create each other through space. Maxwell’s discovery of this led directly to relativity. Relativity is built into his equations. Almost all of physics had to be rewritten after Einstein, but not Maxwell’s equations. They were already relativistic.
As a wave it’s easy to understand how light can have a rest mass of zero. At rest, nothing waves. Light doesn’t exist. Apply an electric or magnetic field under certain simple conditions, and presto, light. Zero to light speed in no time at all. Literally. This can only be possible if there is no mass involved. Oh, and no time also. Oh yes, no distance (space) either.
This jives with what we encountered earlier: time doesn’t exist for light. Neither does space. Or mass. From the point of view of light, light doesn’t exist—or anything else. For light, nothing exists or ever could or ever will. It’s not just zero existence, its null existence. Not even a possibility of a hint of a thought of a potential of existence. Existence itself doesn’t exist.
Really? But it has energy and momentum. As a particle or as a wave, light has momentum.
Like Athena from the head of Zeus, light springs full grown at birth, with momentum dependent on its energy. But from the point of view of a light beam, nothing has changed from its initial null-existent state before a field was applied to send it on its journey (in our view).
Maybe if we can figure out where this momentum comes from, we will actually know something about the origin of our universe, which is all about momentum.
General relativity, Einstein's last and greatest concept, tells us that gravity isn't really a force at all. It's a trick of perception, like an optical illusion, only it isn't just optical.
We are three dimensional beings. That doesn't mean just our bodies, it's our minds too.
As mentioned earlier, physics tells us our universe must have more than three dimensions. How do we know this if we can't see it? Because the physics becomes simpler and more powerful in higher dimensions. What this means is that by assuming higher dimensions, physics makes more powerful predictions about how ordinary matter/energy around us behaves, and those predictions turn out to be deeply true and can be used to do things and build stuff that couldn't be done or built in the same way if they weren't true.
The trick of perception that "creates" gravity for us is the result of three-dimensional beings living in (at least) a four-dimensional universe which is curved in the 4th dimension. The amount by which it curves at any place is directly related to the amount of mass at that place.
Once again, it all seems to come back to mass. We still don’t know where it comes from or what it really is. (The famous Higgs boson is connected with one way of answering these questions, but I don’t think that type of answer interferes with this line of thinking. At some point we always seem to run into the “it’s turtles all the way down” problem*.)
Here’s what I have concluded so far:
Mass is always in motion (all mass has momentum).
You can’t have motion without mass because something has to move
You can’t have motion without space because it has to move somewhere else
You can’t have motion without time because it takes time to get somewhere else
You can’t have space without time, because anything has to have a duration in order to exist
You can’t have time without motion because motion is all we know of time.
You can’t have space without motion because you can’t have space without time.
Space, mass, motion, and time seem to be so intimately connected that one cannot be said to be more primal than the other. The four together appear as momentum. Time implies motion which requires mass and space. Mass increases with motion. Space and time decrease with motion. Mass + time + space equals momentum. Momentum is like Shiva--creator, preserver, and destroyer.
So the mass question can now be restated: where did momentum come from?
The outlier that may shed light on this is light.
*The reference is to a story of someone contending that the earth sits on the backs of a series of tortoises. Upon being challenged by the question “what does the last tortoise stand on?” the answer was “it’s turtles all the way down”.
We think of matter as solid---"real stuff", so to speak.
When you get right down to it, the subatomic level, it's actually mostly space. That's OK in physics because if it's more like energy than matter, who cares? They're just different versions of the same thing, and both have mass.
So where does mass come from?
I think it's interesting to consider those things that are known to have a zero rest mass. Light, for example.
NOTE - I'm going to diverge from general relativity and ignore quantum mechanics for a little while.
Light may be thought of as a particle that travels at, naturally, the speed of light. Now no particle with any amount of mass can travel the speed of light. If you try to accelerate it, its mass increases without bound (to infinity as it were) as it approaches light speed, and there isn't enough energy in the universe (or anywhere else) to get it over that hump!
It's easy to see that light can't have mass. Oops, but it does. The trick is it has no "rest" mass. If you could catch it and stop it, it would have zero mass. That means no matter, and no energy. To me that means it wouldn't exist. We can't stop light, so light keeps zipping around the universe at light speed with measurable mass, and with completely verifiable existence. Sort of like the shark that has to keep swimming in order to stay alive.
Now-- We have to remember we are dealing with things that have no common analogies. It's understood that when the conceptual model fails, it's the fault of the model, not something fundamentally wrong with the physics. The physics works. When you assume what Einstein discovered and make predictions and build rocket ships and such, the predictions and the rocket ships work.
What philosophy tries to do is discover what the physics tells us about the circumstances of our existence, always remembering that we are part of a closed system. Our timelike, spacelike universe is all we know. That means (as Plato observed) we can never really see our universe as it is. A part of something can never see the whole of which it is a part.
So, knowing that there are limitations to my train of thought, I proceed. I'm not proving anything, just offering evidence for certain general conclusions that I believe have other paths leading to these same conclusions.
But I digress...
The other thing of interest with light is another couple of results of special relativity;
1) Anything approaching the speed of light not only increases in mass, its experience of time decreases. Time slows down. At the speed of light, time stops. Once again, nothing matterlike can achieve this. If the infinite mass problem weren't insurmountable (which it is), you can't continue to accelerate as time slows. Actually, the faster you go, the slower you go! 60 miles per hour becomes 60 miles per day becomes 60 miles per week, becomes 60 miles per month becomes...etc. It's like...no, it's exactly the same as...a bad dream.
2) Any thing approaching the speed of light not only increases in mass, and its experience of time decreases, it also gets shorter. It decreases in space in the direction that it is traveling. At the speed of light its length in this direction is zero!. I don't have to tell you that this third strike against anything material is just as convicting as the other two as far as actual existence goes.
So light travels at the speed of light but with no time and no space.
Light at rest can't exist because it has no mass and therefore no matter or energy. Light at the speed of light is without time or space. Sorry. Not only is light unable to exist like this, from light's point of view the universe can't even exist.
As for its velocity, to back up to very basic physics, there is no motion without time, so the speed of snail is impossible, let alone the speed of light. One way out of this conundrum is that time and space stops only from the point of view of light. The rest of us left in the dust still have time and space, still see light moving, etc.
Still, I'm left uncomfortable that something that from its own point of view doesn't exist has mass and velocity and thus, momentum--the fundamental characteristic of our perceived universe. Imagine yourself as light. If you really didn't exist, wouldn't it be offensive that someone was using you to write blogs by? Sort of ghoulish, I think.
Where will this go?
Well, one thing I want to take forward is the connection between mass and motion.
What is mass? Where did stuff come from?
According to Einstein, mass comes in two forms: matter and energy. They are the same thing, sort of like ice and water, related by the iconic equation E=mc^2. (The ^ is a way to indicate a superscript when your keyboard can't do that).
A short, but significant digression-- c is the velocity of light and m is mass as matter, so mc^2, which is equal to mc*c, which has mc in it. mc is mass times a velocity which is what? Momentum!
E=mc^2 says that matter has energy. That's been pretty obvious since the last months of WWII. However, it also says that energy has mass just like matter.
This is not so obvious. When Einstein published his general theory of relativity, one of his results was that since light has energy, it must have mass, and therefore must be affected by gravity. (This is not how physicists usually put this, but it's still true in the context of this discussion.) A few years afterwards some other scientists showed that indeed, light rays are bent by gravity and by EXACTLY the amount that Einstein predicted.
But let's look at ordinary matter. The most obvious difference between matter and energy is that you can see matter. It's pretty solid and doesn't generally move unless something moves it. That's one of Newton's laws (I can't ever keep the numbers of those straight.)
Unfortunately, the closer you look at matter, the less solid and static it turns out to be. In fact, everything is always moving! If the molecules are not moving, they are certainly vibrating, and the electrons are going around the nucleuses (I mean nuclei), The neutrons and protons are vibrating, and who knows what the quarks inside them are doing, but you can be sure they're not napping.
In fact there is no such thing as matter at rest. This is weird.
To be continued...
The basic equation is p=mv. "p" stands for momentum (I guess because m was taken), "m" is mass, and "v" is velocity.
So momentum is mass that is moving.
Starting with the fundamental machines that we heard about in elementary school (lever, inclined plane, etc) all the way to the motion of the stars, galaxies, and clusters, and even the energy flows at the surface of a black hole, that's what physics is about: moving things.
There's a lot left unexplained in this, e.g. what is mass, why does it move, and where does it go?
Starting with "where does it go?" the answer has to do with space. If something moves from one place to another there is a distance between those places and a direction from one to the other. My mathematical model of the creation of space was less than satisfying, maybe physics can do better.
So physics says that the universe had a beginning. This seems to mean it didn't always exist. Space, mass, motion---all this started at some point in time. But wait! It turns out that time is part of the universe, so time...what did time do? It began? But a beginning is a point in time, without time how could time begin? Actually, how could anything begin without time?
I guess we need to know what time is. First how do we measure it? We measure it with clocks. There are many kinds of clocks but they all count periods of moving things. A clock goes around or digitally progresses through 12 or 24 hours and then repeats. Atomic clocks count the number of pulses or cycles of certain atoms.
Of course, this measures time in units of time. That's like measuring feet in units of feet, like telling you that a distance of 4 and a half feet is exactly 4 and a half feet long. You should think about that some. It's subtle. If the rate of time were changing we would never know it. All the clocks would speed up or slow down together, including all the human thought processes, so we would never be aware of any change. This kind of thing is commonly known today as part of Einstein's special theory of relativity, that time is not constant under certain conditions. These conditions have to do with motion. You can't have motion without mass, and mass in motion is momentum.
I'm going to jump to my fundamental definition and say that for us, time is the motion of mass, which is momentum. Time is momentum.
So the "beginning" (I'm very leery of that term) of time is the beginning of momentum, which is the beginning of mass and motion.
Was space already there? I don't see how it could be without time for a lot of reasons. (I'll come back to this later.) So add space in there too.
We're looking for the beginning of time, mass, motion, and space all together.
Since we have to have mass in order to have motion, maybe mass is the fundamental concept of the universe.
More on this next time.
So in order to have dimensions we have to have space.
What, then, is space? Well space takes up space...uh, I mean... space extends somewhere...that is, its size can be measured or estimated in all directions...OK, damn it, it has dimensions!
So when we're talking about dimensions and space, we're talking about the same thing. (I'm leaving out time for the time being, but that will turn out not to be a problem, at least no more of a problem than time already is.)
So where did space/dimensions come from? The only answer that's possible is nowhere, which is a problem.
A model comes from mathematics. We start with a dimensionless point (We can do this in math, but not in physics. That's why mathematicians aren't physicists). This dimensionless point doesn't exist except in the minds of a few mathematicians.
Then they start it moving. (How something that doesn't exist can move is just not asked.) When it moves it traces a line. A line has one dimension. This dimension didn't exist before the point moved, so it moved into space that didn't exist before either. It defines this space. It's a pretty meager space, because it has no width or height, so can't exist in physics anymore than the point can.
Next they take the line and move it sideways, creating a plane with another dimension. This plane still can't be real because it only has length and width, but zero height. However, in the minds of our fictional mathematicians (physicists tend to think of mathematicians as fictional anyway) a new dimension has been created.
At the next step, the plane moves up and traces a volume and a third dimension. Hooray! We have three dimensions-reality!
But wait, the mathematicians find another direction to move the volume that isn't right or left, back or forward, up or down, and they do this, thus creating a 4th spacial dimension and what they call a hyper-volume. We can't see this, but obviously if it's there, our 3 dimensional volume wasn't real either because it was zero in this 4th dimension. As we determined before, that means it didn't exist.
So where does one of these spaces/dimensionalities become real? Sorry, but that's not clear at all.
It is tempting to say that it's real at three dimensions "as everybody and their mother knows" and those pesky mathematicians just don't know when to stop.
Unfortunately,,,and grudgingly...the physicists sidle over with the mathematicians, at least for a few dimensions more and tell us, actually, yes, Virginia, there is a 4th dimension, and a 5th and a 6th, but definitely no more than 10...or maybe 11...but definitely no more than that. (Unless that guy in the corner is right and there are actually 16 dimensions..but no more!).
All this time the mathematicians are happily creating branches of math that deal with infinite dimensions, hierarchies of infinite dimensions, and other monstrous concepts that, sadly, are all based on simple principles that even our measly three dimensions show are obviously valid.
Where does that leave us and our terra firma universe? A little like the coyote who hasn't noticed he's run out of mountain and is backpeddling on thin air.
Don't worry though. As Einstein pointed out, even if this world is an illusion, it's a persistent one.
OK, assuming there is space, where did the stuff that fills it up come from?
Next time; "The Essence of Physics, or Why Shit Does Stuff"