A while ago I went for a run in a ravine I like to jog in. The creek was high and deep with water from spring run off. So I was enjoying the evening and was trying out a few of the less traveled trails that crisscross through the bush and cross the creek at various places with the help of fallen tree logs.
Yeah. You can guess the rest I’m sure.
I started across one of these log bridges and as my foot pressed down on the edge of the log's tree bark, a small piece of it suddenly broke away and I went flying headfirst right into the creek. Completely underwater. So now I was drenched and still 3 miles from my place. It was a chilly, clammy run back home all the while enjoying the snickers of anyone I passed on the way. "Nice day for a swim?"
Gravity sucks.
Later, after I showered and dried, I was sitting thinking how nice it would have been to be able to just turn on some sort of anti-gravity device and float across to the dry creek bank on the other side, skimming above the surface of the water. Just like in my nighttime dreams. But that wasn’t possible and it all compels me to bring up a few things that have bothered me for quite a while but I’ve remained quiet about.
O.K. so here it is.
I really have a problem with the world’s current concepts of gravity.
Old Isaac Newton came up with a series of rules (that have since become ‘laws’ in our science) describing how gravity acts and how objects react to its forces but he never really explains exactly what the source of this gravity energy is. Neither does modern science right to this day, actually.
No one really says from where gravity exactly gets its energy.
There's been some good guesses but it's something still evading us.
Einstein came up with a more complicated description of gravity than Newton, that involved a theory of the bending or curving of space-time that creates an illusion or perception of gravity in our universe. More specifically, we experience a sensation of gravity because space-time is curved by the great mass of our planet and we, the tiny masses existing on it, are directly in the area of this curvature. This whole concept is quite interesting but a bit complicated so unfortunately it is very difficult for most people to visualize or comprehend fully in their own minds.
There are some common, simplistic analogies that are presented in the multitudes of textbooks out there, that try to explain General Relativity but they are mostly unsatisfactory. They usually only scratch the surface and generally never reach the crux of it. Non-euclidian geometry approaches advanced concepts in spatial relations and is an unnatural, difficult train of thought for people to entertain. In fact, most universities and colleges seldom teach it in any depth at all and even the space program tends to use Newton's gravity equations and concepts to deal with and make gravity calculations, since they are usually adequate in solving the situations that come up in normal, everyday situations.
But Newton’s stuff has a few strange quirks or contradictions that arise if you explore it in detail.
This is indeed the reason that Einstein felt the need to come up with a more comprehensive description of gravity in the first place. Newton’s theories and equations break down when you start applying them to tremendously massive objects or objects travelling at huge velocities. Einstein knew that if a law can't be applied universally, it can't really be called a law.
Newton's explanations have some holes in them.
What kind of holes? What kind of contradictions?
Well, Newton suggested that this ‘force of gravity’, that he came up with back in 1687, was like a rock tied to a string that was being swung by a person standing on the ground. The person swings the rock around and around in a circle above their head similar to how the Moon swings around and around the Earth. Gravity, Newton suggests, is like the string, in that it holds the rock in ‘orbit’ around the person just as real gravity holds the Moon in orbit around the Earth. Most people tend to be happy with this explanation because at first glance it appears logical but it doesn’t feel quite right to me. The string isn’t like gravity. The string has mass and is an actual object connected physically to the rock from the hand of the person swinging it. If you wanted, you’d be able to actually measure tension and stress attributes of the string itself as it strained against the centrifugal force of the rock. Gravity on the other hand is this invisible, unseen, mystical bond ‘holding’ the Moon in a circling orbit around the Earth. The string and gravity aren’t equivalent, they only appear similar because they look similar, geometrically. Society has mistakenly made the leap in logic to accepting this example as a way to describe this force called gravity. But the string analogy and gravity aren’t actually very similar at all.
If you’ve ever swung your niece or nephew around and around by their arms in circles on your front lawn while you went dizzy in the process, you can appreciate that this game takes effort and after a while you tell them the rides are over because you’re tired. Swinging an object around and around while you hold it either by the arms or a piece of string takes energy and eventually your muscles get tired of the exertion of pulling it inwards as it tries to fly outwards. Yet the gravity that holds the Moon in a near circular orbit around the Earth never seems to ‘get tired’ from the effort. The tremendous energy it must take to keep an object as huge as the Moon from flying off into outer space is attributed simply to one word, ‘gravity’. Millenium after millenium this force holds the big rock of the Moon in a near perfect circle around the Earth and never gets any weaker. There is no drainage of a power source. Today it holds the Moon just as easily as it did yesterday and will tomorrow.
Just look at this picture. This is an actual scale representation of the Earth's size relative to the Moon's size. The distance between them is to scale also. It's like saying a basketball made of iron sitting way out in space could hold a baseball made of sandstone placed that far away from it due to its mass. After all, gravity between two objects should be the same no matter what scale you make them as long as they maintain their exact proportions relative to each other, shouldn't it? But it's hard to perceive this in our minds because in our experience we don't generally notice gravitational interaction between any objects with masses so much smaller than the Earth's, Sun's or Moon's.
One of my favorite laws of nature is the law of 'Conservation of Energy’. It basically states that energy can’t be destroyed or created. It merely changes from one form to another. You can never get more energy from something than what was potentially there to begin with. You can’t ever get energy from nothing. There is no such thing as a free lunch. In fact all the energy and potential energy in the entire universe is in existence right now and will never be more or less, ever.
So maybe you can now see my first problem with gravity. It would appear, if the force of gravity is indeed a reality, then it is a force able to exert great energy in keeping the Moon in orbit about the Earth yet there is no actual evidence of the transmission of this energy across space and the source of this supposed energy, the Earth, never shows any sign of becoming ‘weaker’. Gravity has never revealed a source of generation. If something was putting out this much energy, over millions of years, to hold a heavy object in orbit around a planet, wouldn’t that energy be expending itself? Wouldn’t the power source gradually deplete its stores of energy and become weaker over time? Where does gravity actually tap into to acquire this incredible energy, what is gravity’s power source? Doesn’t it appear that energy is coming from nowhere? Isn’t this a violation of the laws of physics?
I’ve often asked people a lot smarter than I could ever hope to be, these same questions.
Well, they’ll say, gravity comes from the mass of a body. It’s a consequence of the mass of an object. The more massive the object, the greater the force of gravity around it. The less massive, the less the gravity force. (Always vague answers that are more circular than informative).
O.K. If that’s the case shouldn’t the mass of the object decrease over time as the gravity energy is used up? Saying that gravity is directly related to the mass of an object suggests that it must somehow derive energy from it either partially or totally. But this isn’t the case at all in real world experience or measurement. Mass doesn’t decrease simply due to the existence of the force of gravity around it. It suggests that gravity doesn’t get its energy from the mass of the object at all. But in any case, the transmission of this energy should certainly be able to be detected in the process of traveling from the source to the affected object. This is never the case. You can’t measure the energy of gravity in any way, only it’s assumed, perceived effect on objects within its influence.
Einstein showed us that gravity and acceleration are essentially the same experience. If a person is inside a closed elevator way out in space, with no windows, and the elevator compartment suddenly started accelerating upwards at 9.8 meters per sec2 (the acceleration speed of objects falling in Earth’s gravity) that rider wouldn’t know if they were on an accelerating elevator in the middle of space or standing in a motionless one on the planet surface. The experience would feel identical to the rider in each case. This suggests that acceleration and gravity feel identical. And indeed, this is the case.
Except there is a glaring difference between the two. To accelerate anything you need to apply energy or a force. For example, to accelerate a vehicle from a dead stop you step on the gas pedal and a whole series of mechanical processes convert the gasoline in the fuel tank into forward motion of the car. Take your foot off the gas pedal and soon you coast to a stop. Yet gravity appears to need no such input of energy to create its forces and it never seems to decrease or disappear within the area of its presence, suggesting a magical, endless power source of energy that never gets used up or changes.
This is contrary to the laws of physics and the law of conservation of energy.
Here’s another strange thing.
To block light you simply hold a sheet of cardboard up into its path and the light can’t continue on. Or close the drapes and light is blocked. Even if you increase the electromagnetic frequency of the light high enough to create X-rays, you can still use a material like lead to block its continued travel. Similarly, if you have bare copper wires with electric current flowing through them, you can cover the wires with insulating rubber or plastic and this prevents the current from leaving the wires and affecting your hands and body or anything outside their medium of travel. You won’t experience a shock. You can insulate the world outside from the force of electricity flowing in the wires. And so it goes with many other energy forces of nature.
Yet with the force of gravity there isn’t anything we can insert between its assumed source and the object that it is affecting, to cause it to not do so. You can’t put something between the ground and a picnic table, for instance, to cause the picnic table to suddenly become insulated from the effects of gravity and cause it to float in the air, above the ground. There isn’t anything we can place in the direct path of the supposed source of gravity (a mass or the Earth), and the object it affects, to cause this gravity force to neutralize or weaken on the object.
This inability to insulate or isolate this force or interfere in its medium of travel or with its path suggests that it truly isn’t a force at all but only a by-product of something else that makes it appear to be a force of energy. This would make sense to me because otherwise it would appear that gravity has special privileges in nature when compared to other forces of energy in the universe.
But let’s go on. There’s more strangeness.
Consider two objects falling from a great height above the Earth. Let’s assume one object is a small glass marble measuring an inch across while the other object is a huge, dense block of iron, 1000 feet cubed. If they drop from an exact same distance above the surface, at the exact same time, they will fall and hit the ground below at exactly the same time also (barring any wind resistance or other outside forces beyond that of only gravity).
This is strange. Gravity appears to be a force that seems to accelerate any object, no matter its size or mass, at exactly the same rate with no noticeable stress on the object itself as it plummets. Nothing seems to be pushing on the object or pulling on it. It doesn’t distort or contort. In fact, if you think of it from another point of view, it almost appears that the object is hanging in space and the Earth is speeding up towards it. If the ‘force of gravity’ is indeed a force then it must expend energy to move or hold anything in its domain. It must follow the rules of nature and physics just like any other energetic force in our universe. Isn’t it strange that it appears that it can move a tiny object or a much, much larger object like a huge meteorite with apparently the same easy effort and with no visible or measurable expenditure of energy?
If the speeds of travel are identical then the effort expended must be variable since the objects have variable mass. Gravity must be pulling on the heavy thing harder and on the lighter thing with less force? But this would mean it isn’t a constant force in proportion to the mass of the planet but its strength appears to be dependent on the mass of the objects it is pulling? This is another contradiction.
Yet, in spite of this weirdness, creative physicists and mathematicians will simply tell you that when the massive object was lifted to a point high above the Earth, in the first place, to be dropped from there, that process instilled potential energy in it. They say you're 'charging up' the energy of gravity by moving a mass upwards, waiting for its release to fall back down to Earth. Someone had to burn a lot of fuel just to lift that thing up there so you're, in effect, loading the 'spring' of gravity, we're told. But then I'd have a question to that. Where exactly is that huge pile of energy being stored while we wait for someone to release the object from way up there, to let it fall back to Earth? What place, specifically, is being 'charged up' or loaded with energy by lifting an object on high? And if there is such a place shouldn't I then be able to reach over and just take that energy from this storage place and use it for something else, kind of like a battery? Energy is energy after all. Yet no one has ever been able to identify this theoretical place of energy storage.
Physicists and mathematicians have even come up with clever little equations that they say explain away the reasons why gravity doesn’t show a source of power. There is, in particular, a fancy little ‘work’ equation that explains that because there is no practical lateral or longitudinal movement of objects with respect to gravitational pull, but only an application of force 90 degrees to the surface of the massive planet, no useful work is actually being done and therefore no energy has been expended. It’s a little equation that suggests this but like so many equations, it was improperly assumed that it could be applied to a concept of gravity even though it was designed initially for computing things like steam engine performance, etc. I’d challenge these physicists to actually sit on the Earth and hold the Moon in their outstretched arms as it flung itself in orbit around the planet, day in, day out, trying to free itself from orbit and their grasp as it circled endlessly around. Then after a year or so of that I’d ask them if their muscles felt a little more tired now than when they started and if they still believe no energy was being expended in the task of holding this object in orbit. This same reasoning and equation would claim to prove that a man pushing and straining against a gigantic boulder for hours and hours but not moving or budging it even a millimeter will have expended no energy during this time. Tell that to the exhausted, sweaty man and see what he thinks. A fancy little equation doesn’t invalidate actual real life experience, no matter how clever it may be.
Anyway, I have a couple more troubling things...
Another leap of logic made by Newton that we seem to accept without question is his description of how he came up with the idea that orbits around the Earth are only fancy extensions of the force of gravity acting on an object beyond the curvature of the planet.
He first observed a cannon shooting a steel ball a relatively short distance, in a horizontal velocity, to the surface of the Earth. He noticed the ball will travel at the velocity imparted to it from the explosion of the gunpowder but over the distance of it’s flight it would be pulled to the surface of the Earth by gravity.
Of course Galileo, years before, had already done research on this exact effect and had even created a geometric equation that can predict the path the steel ball will travel for any strength of horizontal velocity. It is interesting that no matter how fast a steel ball is shot horizontally from a cannon or rifle, it will always fall to the Earth at exactly the same rate. If you shoot a gun perfectly horizontally and at the same time drop a bullet slug from the same height with your other hand, both bullets will hit the ground at exactly the same time even though the one shot from the gun will do so at a very long distance away from you.
Newton then stretched his observed cannonball scenario even further in his mind and stated that if you could shoot this same steel ball at such a velocity that it went past the horizon, beyond the curvature of the Earth, it would fall continuously through the space beyond the Earth, in a circle, in orbit and eventually travel right around the world and hit you in the back of the head. He said it would continually fall but because it was beyond the curvature of the planet, and therefore the ground, it would effectively become an object in orbit around the Earth just as the Moon is, continually free-falling due to the force of gravity, around and around the planet. He said that this is how the orbit of the Moon worked.
But there's something obvious to this that makes it a bit troubling. The flight path of any object moving under the force of gravity is always parabolic because the rate of acceleration of objects under the force of gravity on Earth is 9.8 meters per second squared! In fact this is the ‘bread and butter’ theory used by armies to make sure their big guns and tanks shoot shells where they want them to land. A parabolic path is very different from an orbital near circular path! A steel ball fired horizontally beyond the curvature of the Earth would follow a natural parabolic path and fall back to the surface of the planet. A parabolic path always curves back to the surface of the planet no matter how stretched out it is. Unless an projectile can pick up some additional velocity and energy once it escapes the Earth’s atmosphere, it can never go into permanent orbit. In fact, the word 'orbit' could be considered a relative term, depending on the timespan which you're viewing its existence in.
Allow me to try to make this a bit clearer.
A satellite in circular orbit has a constant speed which depends only on the mass of the planet and the distance between the satellite and the center of the planet -- just as gravity close to the Earth surface causes objects of different masses to fall at equal speeds. Generally speaking, the mass of the object in orbit doesn't matter as much as its speed. A satellite in orbit moves faster when it is close to the planet, and slower when it is farther away. When a satellite falls from high altitude to lower altitude, it gains speed, and when it rises from low altitude to higher altitude, it loses speed.
Consider a space shuttle in orbit. They fly these things out of the atmosphere to the space directly beyond our planet and point them in a lateral direction around Earth. They like to say that the vehicle is in free-fall around the Earth and it will complete an orbit every 90 minutes or so. But without additional energy provided by thruster rockets to push the vehicle and speed it up every once in a while, after many loops around, it's orbit slowly decays and the craft would eventually fall into the atmosphere and burn up, just as satellites do. This is because it was never in true orbit afterall, but just on a very, very long parabolic path that eventually leads right back to the surface of the planet. Just like a cannonball.
Also consider geo-synchronous satellites that are put into orbit 22,300 miles above the planet and maintain an orbit over a constant point on Earth. They've been moved into a higher orbit so their speed is a significant decrease from that of the space shuttle and it takes them 24 hours to complete one orbit. These usually provide telecommunication or weather functions. But they are no different than the space shuttle even though they appear motionless above us -- they too are in a parabolic tragetory that naturally degrades over time and they will very slowly sink back towards the surface of the planet. Without the application of some sort of energetic force to increase their velocity and stretch out their parabolic arc once again, they too will eventually degrade in orbit and burn up in the atmosphere. I realize this will take a very, very long time but it is still a degrading orbit nonetheless.
But now consider the Moon. It moves around the Earth-Moon center-of-mass in a near circular orbit and has been doing so for billions of years. We like to be told that it is simply in free-fall around the Earth and it's orbit is a consequence of the force of gravity from the Earth acting upon it and its own centrifugal force. However if it is moving at constant horizontal velocity in free-fall past the curvature of the planet like the shuttles and satellites, Newton's force of gravity also has to pull it to the surface of Earth, no matter how large a mass it has! It must follow the same rules and would have to conform to the same parabolic trajectory of bullets, shuttles or satellites. But this doesn't appear to be the case with its orbit and I don't know where the Moon would get an extra 'push' every once in a while to correct a degrading orbit. I realize that the degrading orbit of the Moon would take literally billions of years to take effect but what's curious is that it's already been orbiting there for at least 4 or 5 billion years (that we can guess) yet laser measurements of the distance of the Moon from the Earth confirm it's actually very slowly orbiting further and further from the Earth, even within the microscopic span of time we've been making them, contrary to what you'd expect if the force of gravity was pulling it in over time. It appears to be slipping away.
The last thing that bothers me about Newton’s gravity is that it is tied directly to the mass of an object in a way that suggests the mass must actually generate the energy of it. We say our Earth is held in orbit around the Sun because the Sun’s huge mass creates a force of gravity that holds all it’s planets in place in the solar system. Yet imagine the Sun suddenly disappearing or zapping out of existence. By the laws of gravity from Newton, the Earth should instantly be free from its orbital path and immediately fly off in a straight trajectory out into space. In fact, this should happen even before the light from the vaporized Sun reaches us! We’d still be looking up at a nice bright sunny day and suddenly our planet would go flying off, veering into space without us knowing exactly why because it takes approximately 8 minutes for light to travel from the Sun to us but loss of gravity, according to Newton, would be felt instantaneously.
This is a contradiction of the laws of physics, as we know them, as well. Nothing can ever travel faster than the speed of light yet this phenomenon of loss of gravity was an instant transmission of a situation across space to us. There was no 8-minute delay in the change of gravity! This suggests we should be able to somehow create gravity based communication systems that could communicate information across vast distances like the galaxy or more, and be able to do so instantly, regardless of the distances involved. This seems too fantastic to be true and it probably is. But the law of gravity as it exists from Newton suggests that this could be possible.
So where are we at?
Where do we go from here?
Well, Einstein’s gravity theory makes more sense of things even though most of the equations are too complicated or involved to be used practically in everyday required calculations. He's even suggested that gravity is like an extremely weak type of electromagnetic wave (except it can't be scattered or absorbed) that does actually require a unit of time to cross a certain distance. In Einstein's world, a suddenly disappearing Sun indeed wouldn't be noticed or felt on Earth until 8 minutes later, along with the extinguished light. But his concepts require us to make mental leaps into realms of space-time that have strange contortions and dimensions that we simply don’t perceive in a tangible way in our normal existence. In a practical sense, the theory is so advanced and clever it quickly becomes not naturally intuitive and is hard stuff to convert to an everyday understanding of what we sense around us.
Please understand, there's nothing wrong with complicated if it's right and symmetrical. However, although General Relativity does OK in suggesting a particular working of gravity in the universe for bodies with huge masses, or normal masses affected by the extreme effects of Special Relativity, it doesn't do so well in the subatomic world. The equations fail to explain the gravitational phenomena occurring at these levels.
So it too, is not a final, universal gravitational theory either.
So now what?
Well, I'm sure that by now you might have sensed that my onslaught and barrage in this article against Newton gravity was meant to be a bit on the tongue-in-cheek side and more as a shove to maybe make you think of such things for a while in unconventional ways. And of course, it isn't Newton's gravity any more than it is Fred Johnson's from down the street. We actually should probably be grateful that thinking people in our history and present times are willing to take a stab at figuring out the mysteries of our universe for the less mentally active among us. *grin*
But we simply don’t have it all pegged down yet, in spite of some really good tries by some very sharp people. The true nature, source, and mechanism of gravity still evades us and we have yet to discover exactly what it is and how it works. Especially in a way that will naturally click in people's minds and make it intuitive. Perhaps one day we will discover even further ways to adjust and tweak Newton's & Einstein's gravity guesses to pull the loose ends closer together. That'll be OK. After all, our confidence flows through the range of conditions over which a law has been tested and verified. The broader this range, the more powerful the law becomes in describing the cosmos and the more valid it is.
For ordinary 'household' gravity, Newton's law works just fine.
For black holes and the large-scale structure of the universe, we need general relativity.
But on the quantum level, where the momentum and position of a particle at that scale can't be predicted unambiguously, we require something more to act as a quantum theory of gravity. (The cornerstone of general relativity is that the momentum and position of objects are defined exactly and at subatomic levels this is impossible).
What's most important to remember is that until we are able to universally apply them everywhere, in every case, the laws we develop are no more than our 'best guess for now' in the particular areas where they apply, however clever they may be.
You must constantly stay aware that it is possible to invent almost any theoretical concept or mathematical equation to justify almost any result we wish to see or phenomenon we encounter. It's just like the ‘work’ equation is used to explain gravity’s apparent lack of a power source. A clever twist of logic that spins a solution out of the air but in real world experience it somehow doesn't feel totally accurate.
Anything done in the name of a discipline sometimes gains legitimacy only because of that fact.
For example, consider the painting consisting of a purely white canvas and nothing else, that sold for over 2.5 million bucks a few years ago. While it was on display as a brave and new concept of art in a gallery in New York, a young boy with his father standing there viewing it, mentioned that it was just a white cloth and he could do the same. The 'art folk' around him simply laughed in good humor at this poor little boy's ignorance, as they sipped champagne in tuxes and evening gowns.
Was he ignorant or perceptive?
Was something being pushed in the name of a discipline even though it didn't merit that position and it only took a little boy, with no stake in the affair, to point out the obvious?
Consider the ‘strong force’ physicists have come up with in recent years to describe a force that seems to hold the nucleus of an atom together.
It has been assumed for a while now that the nucleus of an atom contains protons and neutrons. Neutrons are said to have no charge but protons are thought to be positively charged particles. Anyone knows that if you take two magnets and push the two positively charged ends towards each other, they repel each other and the magnets feel like they’re pushing apart from each other. We describe this situation in a rule that says 'like charges repel, opposite charges attract’.
Well, what should happen in the nucleus of an atom with two or more positively charged protons in it?
These protons should repel each other shouldn't they? Effectively cause the atom to explode -- never staying in one piece!.
But if this were the case, atoms would be popping apart constantly and matter could have never formed in the first place. So to get around this dilemma, scientists have invented the explanation of a force they've called the ‘strong force’. It's this mystical force that is said to exist only in the nucleus of an atom and is so strong it holds the naturally repulsing positive protons together in a tight bundle in spite of their wanting to electromagnetically push away from each other.
Once again we've come up with equations, theory and a new force to explain a phenomena we have noticed in our universe. Is it possible that there is such a force? Sure. Anything is possible I suppose. Is it accurate? I'd say it all sounds a little more convenient than accurate... At first glance it appears to violate already proven laws of electromagnetism, to name only one.
It seems that initial concepts and theories get more and more complicated and layered so that pretty soon it all starts to get very difficult to follow and understand. Patches on top of patches.
Physicists appear to love this. Probably because it gives them more mystique in society in general.
However, my instincts constantly nag me that nature isn’t like this.
If some theory or explanation isn’t symmetrical and smooth, I suspect it isn’t yet quite right and this is definitely the feeling I get about gravity concepts and a lot of other theories physicists are coming up with nowdays.
Are some of them simply caught in that whirlpool of a professional physics culture that has become all about being published and recognized and honored -- maybe at the cost of good science? Caught in a vortex of ever growing, partially flawed theories or steps of logic that cause them to have to be continually patched and renovated rather than scrapping a perhaps fragile foundation to begin with and starting fresh with something cleaner and more sound? Sometimes it becomes hard to tell. Sometimes it seems they’re all trying too hard to get into the history books or get that next grant or to get their name on the Nobel game trophy.
But I'm taking it too political now and I shouldn't do that.
Yes, I totally realize that a genius mind that can suddenly understand an aspect of nature clearly and present something fresh in a way nobody ever realized before, seldom comes around.
It just frustrates me to see the dance scientists do in the meantime. Rehashing, patching, spinning their wheels, beating their chests, pumping up their boots, slapping their backs, while it all gets more and more twisted and complicated.
Is the universe really like this?
It's got to be simpler than all that, I think...
P.S.
I too, have a theory how gravity works. I won't get into it now but if you consider my subtle comment many paragraphs ago of imagining an object standing still in space while the ground of the Earth rushes up towards it...
I think everything is geometrically based... that's all I'll say...
for now...
