I mentioned in the previous installment on
Gravity (July 9th) that the outcome of my thought experiment about the Rock and the Asteroid was predicated on all other external factors being neutral in terms of their impact upon my rock falling through its perfect tube towards the center of the asteroid: There could be no other large masses near the asteroid that might otherwise influence its interaction with the rock; Atmosphere couldn't be a factor, given that it would act on my rock and impede its perfect flight; Magnetism could not come into play; The density of the materials that make up the asteroid could not be greater in one place than another, lest they exert an attraction greater than the rest of the asteroid and impede the rock's flight.
Were there any of these irregularities, the rock would be pulled to one side of the tube or another, and contact with the tube would retard its fall and kill our fun. The rock too would need to have a uniform density throughout its mass, since even the smallest irregularities would cause it to be attracted to the side of the tube where the rock's greater mass resided. Of course, that might be negated by imparting a spin on the rock, which would to a certain extent neutralize the effect of any irregularities in its mass relative to the asteroid's influence upon it.
Interesting to note that even spinning, the rock likely would neutralize the attraction of the asteroid through a single 360 degree plane determined by the irregularities in its mass. It begs the question as to whether a spinning rock of irregular shape and composition would progressively spin in different directions as the gravity of the asteroid that surrounded it exerted its influence. It also begs the question as to whether the gravity from the asteroid might not eventually - or even rather abruptly - cause the rock to stop spinning at all, seeing as how the gravity that surrounded the rock would exert its influence more evenly against every molecule in the rock, the closer it got to the center.
Either way, the whole point of framing the argument in this manner is to justify bringing it into the realm of that which is doable. My asteroid and rock might as plausibly be a boulder and a mote of dust. And how cool would it be to actually test that proposition?
If - as it appears - the force of gravity is effected by mass and distance, it's interesting to speculate that its influence still might be infinite: in other words, that a single molecule exerts an attraction to and on a mass on the other side of the universe. If that's true, then it begs the question as to whether it is inevitable that all matter will eventually collapse upon itself. If it's not true, and the effect of gravity is limited, it simultaneously begs the question of whether or not all bodies in the universe won't eventually fly away from each other, and, what is keeping anything together in the first place?
Extending our little thought experiment from the previous installment, let us contemplate yet again our Rock and Asteroid. I had concluded that - all other factors being equal - dropping my rock down a tube that traversed an asteroid would result in the rock slingshotting back and forth through the tube and eventually floating weightless at the exact center of the asteroid. What, though, would happen if the rock and asteroid were exactly equal in mass, with the rock being orders of magnitude greater in density than the asteroid? Would it still fall back and forth through the tube? Would it still come to rest in the middle of the asteroid, vibrating to stillness? Or would both objects be moving back and forth relative to each other, and both vibrating to stillness? And what would be the outcome if the Rock was actually greater in mass than the asteroid? Might the asteroid move back and forth around the rock?
If we accept Gravity as defined by conventional wisdom, then both objects - regardless of their relative mass - would move as the rock dropped through the asteroid, never mind that an asteroid of lesser mass might more correctly be said to moving around the rock.
I also amuse myself by speculating as to how long it would take for both objects to come to stillness. If the rock was close to equal to the asteroid's mass, wouldn't its travel through the tube be agonizingly slow? And if the rock was very small relative to the asteroid, it would "fall" quickly enough, but the energy built up during each swing should cause it to travel well past the mid-point, resulting in countless iterations as it fell back and forth through the tube.
Makes you wonder if the time necessary to come to stillness is exactly equal for all combinations of the asteroid and the rock relative to mass.
My point in covering this ground yet again is that the interaction of the two objects is affected by the mass of each relative to the other, and that there is a quantifiable dynamic that can be expressed in mathematical terms and that that dynamic can be tested. And if this interaction is consistent regardless of scale, does it not suggest that gravity also exerts an influence regardless of distance?
I'll address that in greater detail later.
From here we must consider the limits of gravity, as it is plausible to assume there are some. For example, gravity does not appear to affect the weak and strong nuclear bonds: neither atoms or molecules fly apart just because there's a large body exerting a gravitic force somewhere in the neighborhood. But, exactly what does it not affect? Or put another way, how low does gravity go? For example, suns, planets and all other celestial bodies are demonstrably influenced by gravity, as are smaller objects all the way down to - I would guess - a single molecule. But when does gravity cease to exert an influence on small objects? Notwithstanding that atoms are influenced by the so-called Weak and Strong nuclear bonds, are individual atoms also attracted to each other by gravity? Are they attracted to larger objects by gravity? Or does gravity only exert itself once atoms are configured in a particular way?
I speculated earlier that every particle in the universe exerts an influence on every other particle. I said that not only because that is what I was taught, but because the physical world - while it does not unequivocally prove such a thing - at least seems not to refute it. Still, it makes you wonder if some additional layer or layers of complexity might not be at work instead. For example, is it possible that a single molecule halfway between Chicago and the moon might exert no influence at all on, say, a distant star, but when that single molecule falls to Earth and becomes part of an unspeakably larger mass that it just might? In other words, might molecules that form some coherent mass exert an influence and effect the laws of physics in ways that an equal number of incoherent molecules do not?
If this is true, might it be possible that gravity would "pull" photons in a direction that would allow it to travel vast distances, farther by far than it reasonably ought to travel based on whatever energy caused its source to emit light in the first place? I can't accept that a single photon would travel indefinitely. It's got to run out of gas eventually. Remember as well my observation in a previous piece about the implausibility of the light emanating from a small star being broadcast with equal intensity in an infinity of directions across the known universe. Simply put, the further the light travels, the less photons there would be for some observer to see such that it could be observed, much less discerned to be a star.
Bottom line, there's some major holes in the notion that gravity or any type of energy - be it light, x-rays, infrared, microwaves - could travel far, far beyond its source and still have the ability either to be observed or to have an influence on objects at some far-gone point. Check out my previous post on this subject:
http://offhismeds.blogspot.com/2012/10/the-implausibility-of-light-as-wave.html.
And yet, we do see the light of stars thousands of light years away, and we do believe gravity exerts a collective influence on the universe. What if some as yet unexplained phenomenon was at work?
My notion here is that there exists some kind of "Ether" that Surrounds Us, Penetrates Us, That Binds the Galaxy Together. Yes, I was just quoting Obi Wan Kenobe. We acknowledge the existence of the various "Forces", including Gravity, Electromagnetism, the Weak and Strong Nuclear Bonds; why not consider the existence of additional Forces, particularly one that was a universal medium that interacted with all of the others? In the case of photons, it would explain why a light signal could span galaxies: it would not be the light itself that we might observe, but a facsimile of that light as received by this Medium and transferred through it. Imagine the ripple that forms on a pond when you throw a rock into it. The rock only came into contact with the water at one point, but its effect could be observed and even felt in the form a wave quite some distance away.
We might correctly conclude that a rock was thrown in the water without necessarily seeing the event, based on previous observations of similar events. We correctly observe that something happened, otherwise the ripple wouldn't exist. In fact, we might reach any number of different conclusions as to what happened based on the nature of the ripple. So, what if the light from a star travels the same way? In a similar manner, what if the effect of gravity over vast distances is not some unsustainable attraction between two objects, but like the ripples on a pond?
We know from observation that there is limited energy to propel the ripples across the pond after the initial event, just as there is limited energy to project a beam of light or for gravity to influence other mass across great distances. That means this Force or "Ether" I speculate about would have to be a form of energy itself - or have a source of energy - in order to sustain the phenomenon of the transmission of light or the effects of gravity across the universe. There's no lack of energy sources to sustain the "Ether": it would seem that gravity, electromagnetism, the weak and strong nuclear bonds would all qualify. For the sake of keeping things simple, Gravity alone might just do the trick. Whether we accept that Gravity is holding the universe together or is failing to do so, we are acknowledging that it has an influence on the entire universe, however imperfect.
Either way, it seems to me that physicists could test the proposition. Maybe I'll write a memo to NASA. They're always looking for things to do, and can focus like a bulldog when they need to.
Footnote:
It so happened that I had taken a break from writing this little dissertation the other day to read up on Sufism. I've been fascinated by this slice of Islam for a long time, since the more conservative strains of Islam - both Sunni and Shiite - appear to tolerate and even honor what can only be described as the Muslim Hippies. My internet search on Sufis led me almost immediately to a 20th century mystic named Bawa Muhaiyaddeen, who wrote: "There are six categories of life, five of which are: earth life, fire life, water life, air life and ether life. Earth life has 400 trillion kinds of lives; fire life has 1008 kinds of lives; water life has 1008 kinds of lives; air has 2008; and ether life (such as that which is found in stars, moon, sun, etc.) has 1008 kinds of lives." It was intriguing to me that he would refer to an "ether" that not only influenced celestial bodies, but that itself comprised a form of Life. That is the essence of what I was trying to say about my "Medium" or "Force", albeit that the manner in which it works is not only not mystical, but downright mundane.
The concept of an Ether is certainly not new in religion, but what I did find interesting was that this mystic would find that a spiritual life would break down along lines similar to the way that science defines the universe. I was also fascinated by his notion that there were 400 Trillion manifestations of life on Earth compared to mere thousands when defining the physical world. While I haven't done the math, that number of 400 million is at least plausible. The lower numbers of "lives" that influence fire, water, air and ether also have a ring of authenticity about them, if you accept that what he's talking about are the physical laws that govern their behavior.
