FORWARD THINKING IN ASTRONOMY [A series of eight lectures specially prepared for Compu- Se

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FORWARD THINKING IN ASTRONOMY [A series of eight lectures specially prepared for Compu- Serve Information Systems (CIS), for presentation in ASTROFORUM. Copyright 1990 by Tom Van Flandern of Washington, DC [CIS ID code 71107,2320]. Please seek the author's permission before reprinting more than two paragraphs. If redistributed in electronic form, must include this statement of source and copyright.] CHAPTER IV. RELATIVITY, AND THE PHYSICAL UNIVERSE A. Waves One cannot study the nature of things for very long before an understanding of waves and their properties becomes an essential tool. When substance is disturbed, individual particles may scatter or behave "randomly"; but the surrounding medium communicates the effects of the disturbance outward by means of organized motions of its own constituent particles. These organized motions in a medium are called "waves". Waves are pulses, sometimes in the same direction as the wave motion (called "longitudinal" waves; e.g. sound waves in air); and sometimes perpendicular to the direction of the wave motion (called "transverse" waves; e.g. water waves, also light). Dissimilar waves from different sources pass through one another without lasting effects -- i.e. they do not exhibit the property of collision, as particles do (although a barrier can be made to reflect them). When water is the medium of transmission, individual molecules of water merely move up and down as the wave passes; they do not themselves advance with the wave. When air is the medium, individual molecules move at extremely high velocities, much faster than the wave itself, colliding with other molecules frequently. The passing wave is merely a statistical tendency for the molecules to collide more frequently in certain locations ("condensations"), and less frequently in others ("rarefactions"). Information about the time and place of some source disturbance is transmitted by the wave, although the molecules comprising it do not themselves share that information. The propagation velocity of the wave is a function of the density of the medium and the speed and mean distance between collisions of the individual particles comprising it. The hypothetical "sea of entitiararae have postulated in earlier discussions, pervading the entire universe, can likewise transmit information by means of waves -- information not shared by individual entities. Although waves in this entity sea are not exactly analogous to any of the other kinds of waves we have mentioned, their behavior will bear many similaritias. Since known waves such as light which can exist purely in this entity sea propagate with the speed of light, we conclude that this is a natural wave velocity of the medium. By analogy with air, however, the velocitias of the individual particles are many orders of magnitude greater than the speed of light, c. B. General Relativity In the case of a wave already traveling at the velocity c approaching a massive body, the gravitational force of the massive body tries to make the wave travel faster than c. However the effect of the imbalance in the number of "gravitons" on the two sides of the approaching wave must be to shorten the wavelength of the wave (increasing its energy), since its velocity is not free to change. We may apply this result immediately to light waves traveling away from a massive body. The light will experience a "redshift" (an increase in wavelength, which represents a loss of energy), instead of a slowing in velocity. This is the so-called "gravitational redshift" of light, one of the three tests of Einstein's General Relativity Theory. Now imagine that the light wave passes close by the massive body. The same constraints apply, since the velocity of the wave cannot itself be either accelerated or decelerated by the massive body. However the wave can be bent by "refraction" in exact analogy to what happens when a light wave passes from a thinner medium into a denser one. It has been shown by many authors that the famous "light-bending" test of Einstein's General Relativity theory can be derived exactly in a model which assumes a flat space-time with refraction in a medium whose wave velocity is c. It even gives correctly the time delay of radar waves in the solar system as a consequence of the slight slowing of the speed of light when traveling in a denser medium near a massive body. We were already aware that light slows down when traveling in denser media, such as water. Although this refraction analogy has been known almost since the General Relativity theory was first published, the "curved space-time" model has received wide acceptance over the "refraction" model for these phenomena because of the failure of experiments to detect the presence of a medium within which light propagates. This has to do with the "Special Relativity" theory, which we will examine in a moment. The third test of General Relativity is the excess rotation of Mercury's elliptical orbit, which has been accurately verified. This, too, may be seen as merely a consequence of the behavior of bodies becoming more "wave-like", including the bending of their paths by refraction rather than by acceleration as they approach the speed of light. Specifically, the contraction of space and time, which are consequences of Special Relativity (to be discussed next), will result in a greater force from the Sun when Mercury is at perihelion (closest point to the Sun) than at aphelion (farthest from the Sun). As is well known in Celestial Mechanics, applying a radial perturbation to an orbit which augments the central force at perihelion, and decrements it at aphelion, has the effect of rotating the direction of perihelion in the forward direction. C. Special Relativity Why do clocks slow down when the speed of a body approaches the speed of light? Clocks, change, aging, and all measurements of time ultimately depend upon the structure of the matter they are made out of. To focus on just one aspect of this, consider the revolution of electrons around atomic nuclei. Suppose every electron in every orbit around every atom took twice as long to complete a revolution (or any motion). Then clocks, aging, and indeed time itself for observers made of such "slow atoms" would slow to half the usual rate. A reason that electrons might "slow down" while moving at high velocities is that it takes longer for them to complete a revolution when their atoms are moving near the speed of light than when their atoms are stationary. This is true of any body traveling in a moving medium. ******** Consider a canoe moving upstream and back downstream to its starting point against a current. Show that the faster the current, the longer the round trip takes. The essence of Special Relativity is that all motion is relative. It is supposed that there is no measurement which can decide that one body is "really moving" and another is not, since the opposite point of view is equally valid. The theory then goes on to propose that moving bodies undergo an apparent contraction of space and time, as seen from a stationary frame: distances seem to be compressed in the direction of motion of the body, and clocks traveling with the body seem to tick more slowly. Although the contraction of space and time is negligible at ordinary velocities, it becomes indefinitely great as the velocity of the observer approaches c. This is often dramatized with an example of two newly-born twins. It is supposed that one of the twins remains on Earth, while the other is placed on a spacecraft moving toward a nearby star (Alpha Centauri) with a speed of 99% of the speed of light, c. We further suppose that the nearby star is about four lightyears away, so that the one way journey takes just a little over four years, as measured by Earth clocks. We then imagine that the traveling twin turns around and returns to Earth. According to Special Relativity theory, the twin who stayed on Earth will be over eight years old when the two are re-united; whereas the traveling twin will have aged only a little over one year, and will still be a baby, because of slowing of the rate of progress of time for any body traveling with a velocity of 99% of c. Traveling atomic clocks have been successful in showing that such effects really do occur, and that traveling bodies age more slowly. We have always known that we could use the average position and velocity of all bodies in a given vicinity as a reference frame for both position and motion. And if some velocity greatly exceeds the motion of any individual body in the vicinity, such a velocity is both detectable and has physical consequences. Only in that sense can it be called an "absolute" velocity. In the universe as a whole, there would be asymmetries in the amount of visible matter in the forward and aft directions; and the cosmic microwave background radiation would be red-shifted in the direction of motion and blue-shifted in the opposite direction. These likewise enable us to detect a sort of "absolute" motion, but only in a statistical sense. With these concepts in mind, let us examine by analogy exactly how and why space and time contract in our model as velocities approach the speed of light; and most importantly, how it is possible for substance to travel faster than the speed of light without violating Special Relativity, and without moving backwards in time, thereby violating causality. ["Violating causality" from traveling backwards in time means, for example, preventing your own grandfather from being born. Since you would then never come to exist, you couldn't do what you just did.] D. The "Sound" Analogy Consider an alternate universe containing "atoms" of unspecified size and mass, each consisting of a "nucleus" exerting some attractive force, and "electrons" in orbit around that nucleus, similar to the Bohr model for the Hydrogen atom. Now let the universe be filled with a continuous medium having the properties of air, and let the electrons of our hypothetical atom propagate through this medium in their orbits around their nucleus just as sound propagates through air. Let the Bohr radius of an imitation "Hydrogen atom" in this universe provide the unit of length; and let the elapsed interval needed for the corresponding electron to circle its nucleus provide a unit of time in this universe. The essential difference between this model and the real universe is that all motion in this model is via wave propagation through a medium in which the limiting propagation velocity is the speed of sound. We will find the implications of this variation familiar. Suppose that an airplane composed of these alternate atoms flies through the air-like medium (assuming no gravity) by means of propellers. Since its means of propulsion is by pushing against the medium (rather than action-reaction, as in jets or rockets), the speed of the airplane is limited to the speed of sound. (The speed of sound is the maximum speed at which waves or pressure can propagate in a medium.) As ever more energy is applied to make the propellers spin faster, the airplane's speed will approach the speed of sound ever closer; but it can never quite reach it, except with infinite energy and infinite propeller speed. To a physicist in this alternate universe, it appears as if the airplane's inertial mass is increasing as its velocity increases. The airplane seems to resist further acceleration as the energy applied approaches infinity because the airplane's inertial mass seems to approach infinity. This is PRECISELY analogous to the way in which the inertial mass of a body in the real universe seems to approach infinity as its velocity approaches the speed of light. As the airplane's velocity approaches the speed of sound, the sound waves emanating from it in the direction of motion get bunched up closer and closer together, because their velocity relative to the airplane gets less and less. For precisely the same reason, the orbits of the electrons in the airplane get compressed in the direction of motion, because they, too, propagate like sound waves in our special universe. But since the dimensions of the electron orbits provide the unit of length in this universe, a physicist in this universe would conclude that distances contract in the direction of motion as bodies approach the speed of sound. Indeed, he would derive precisely the well-known "Lorentz contraction" formula to represent the amount of this contraction. In the real universe, distances seem to be contracted in the direction of motion in accord with the Lorentz formula as bodies approach the speed of light. Moreover, if the matter is judged by a stationary observer, the electrons will take more time to complete their orbits, because the round trip time for any particle moving upstream and downstream in a moving current is greater than the round trip time in a stationary medium. This "time dilation" for the moving electrons of the airplane also follows the Lorentz formula, because the revolution time for the electron approaches infinity as the velocity of the airplane approaches the speed of sound. In the real universe, the clocks of moving observers seem to slow down with respect to those of stationary observers as their relative velocity approaches the speed of light. The contractions of the units of length and time are exactly analogous in the alternate universe with respect to the speed of sound, to what they are in the real universe with respect to the speed of light. So it follows that all observers in the alternate universe performing "Michelson-Morley" experiments, or trying to measure the speed of sound, will get the same constant answer regardless of their state of motion with respect to the air medium, just as that happens for light in the real universe. In fact, all experiments performed in the two universes would be analogous. Even a moving biological twin being made of such hypothetical "sound" atoms would age more slowly than his non- moving identical brother, because the "sound" atoms of which he is comprised slow down in all respects. E. Causality Now because the situation is reciprocal for "moving" and "stationary" observers (i.e. each "sees" the clocks of the other slow down and distances contract, but via waves traveling at the speed of sound, not light), it has been concluded that no experiment can tell which observer is really moving and which is stationary. But we have just described how the same experimental results may be achieved within a medium which provides a "preferred" reference frame. So the conclusion that "no experiment can tell ..." is incorrect. It is possible in principle to measure the average motion of all air molecules in a given volume, and to adopt that average as a standard of rest. Of course there might be a "breeze" blowing through our entire adopted volume, so that it does not provide an "absolute" standard of rest for the alternate universe. But it would provide a preferred frame for any volume of arbitrary size. In the real universe, we propose to make the same remark about the sea of agents, the presumed medium for the propagation of light. Any experiment which could measure its statistical properties could determine a preferred frame. There is one more important point to consider. In the real universe it is concluded that faster-than-light communications would violate causality because they would propagate backwards in time. In our alternate universe we may see a similar line of reasoning if all communications were limited to the speed of sound. The fact that atoms and clocks would slow down as they approached the speed of sound, and that the electrons would reverse direction if the speed of sound were exceeded, does not alter the forward flow of "meta time" as kept by clocks fixed in the preferred frame. Indeed, the phenomenon of "slowed time" may be seen as a consequence of using imperfect clocks which depend upon the speed of propagation of waves through a medium. An observer could choose to use "meta-clocks" which do not depend upon the speed of sound or the properties of the medium they reside in. Against such meta-clocks the observer could measure the slowing of his own imperfect clocks and of his own biological processes as his velocity increased. If a physicist in the alternate universe could devise a way to construct an enclosure out of matter from our real universe, it would not be subject to the speed of sound limitations in his universe. Such an enclosure could fly through his air medium at any speed whatever, shielding occupants within (still composed of "sound" atoms) from experiencing space and time contractions. By analogy, if real physicists could find a way to construct an enclosure out of substance which was not subject to the limitations of ordinary matter (all electromagnetic forces propagate at the speed of light), then they too could move through the universe faster than light without suffering space- time contractions -- or violating causality! If the reader accepts this analogy, then we have demonstrated that wondrous things are possible. Although it may be that our starting point is incorrect, nonetheless if it is not, then faster-than-light travel is possible. And if there truly is a "sea of entities", then there will be no such thing as "black holes" in the usual sense, nor singularitias in nature. Dense masses will be capable of shielding some of the matter in their interiors from acting on the external universe (a violation of the "Universal" Law of Gravitation), which would prevent escape velocities for such dense masses from ever reaching or exceeding the speed of light. There may come a day when we master the utilization of the entities through which light propagates, using them for communications as easily as we have now mastered the use of light itself. F. The Big Bang Universe Our examination of the large scale structure of the universe would not be complete without adding some obvious corollaries of the assumption that it is infinite in extent, time, and scale. At SOME level of scale, whether that be "super-bubble-clusters" or well beyond, the structure may become non-uniform in the extreme. It may appear at first that there are limits to the matter in the universe; but we will eventually discover that other such super-super structures exist at vast distances. It will be analogous to finding the limits of stars within our own galaxies, later to discover that there are entire other galaxies at vast distances beyond ours. Related problems for the Big Bang theory are that the distribution of matter on the largest scales is supposed to be uniform; and the highest redshift galaxies should consist of only very young stars. The highest redshift quasar to date, 4.73, has an ordinary spectrum, implying roughly the same materials and evolution as later galaxies. And the smoothness of the cosmic background radiation ("the heat left over from the creation of the universe") contrasts with the lumpiness of matter in galaxies, clusters, super-clusters, and bubbles. If the universe is infinite in extent, duration, and mass, how can such an idea be reconciled with the Big Bang theory, or with the observed "expansion of the universe", or with the universe's "observed" age? All of modern cosmology is based ultimately upon a very small number of observed facts, the chief of which is that the further away a galaxy is, the more its light is redshifted. For lack of any better explanation, the redshift of galaxies has been assumed to be due to a velocity of recession. Hence, the further away a galaxy is, the faster it is receding from us (and from all other galaxies). A traceback of these fleeing galaxies with their "observed velocities" tells us the "age of the universe" -- the time when this expansion began. The theory which explains the beginning of the expansion of the universe in an explosive event is called the Big Bang theory. We also observe a cosmic microwave background radiation nearly uniformly around the sky, with a peak temperature of 2.78 degrees Kelvin, which is interpreted as the remnants of the "fireball" from the Big Bang explosion. A third observation useful to cosmologists is that, if redshift (z, the ratio of cosmological wavelength to local wavelength for known spectral features) is interpreted as a velocity indicator, and if velocity is a distance indicator, then the space density of radio galaxies increases at one goes further out into the universe. The redshifts and the microwave background radiation are observed facts. It is easy to forget that their interpretation as velocities and fireball remnants, respectively, is theory. There is nothing compelling about these interpretations; they were merely the best available explanations at the time they were thought of. We must continually evaluate whether or not these theories continue to be of value (i.e. make useful predictions), and whether they continue to be supported by newer observational data. Arp's book, "Quasars, Redshifts, and Controversies", offers compelling evidence from many different sources that at least some galactic and quasar redshifts are not due to velocity. But if some are not, then we must question whether any large redshifts are due exclusively to velocity. Indeed, we must question whether it is reasonable to continue assuming that the universe is expanding at all. Even if Arp were wrong about all of the evidence he presents, it would still be reasonable to question the velocity interpretation of redshifts. There is, after all, next to nothing in the way of evidence that the redshifts ARE due to velocities. It is merely the case that objections have been raised to all other possibilitias proposed to date. G. The Weak Light Universe It has been proposed by many authors that redshifts of distant objects may be in part due to a loss of energy of photons which have traveled very great distances. The objections to this idea, called the "tired light" theory, are twofold: (1) If the energy losses are due to interaction with particles in space, the resulting "scattering" effect on the photons would prevent images of distant objects from being sharp in our telescopes. (2) Type I supernovas from extragalactic sources have their lightcurves stretched out in time as expected if the galaxies are truly receding from us at their redshift velocities, but not as expected if their relative velocities are much lower. However we can readily visualize that a sea of gravitons traveling many orders of magnitude faster than light would not necessarily be subject to these objections, because the energy losses would be slow, gradual, and continuous. Let us describe this new variation of the "tired light" theory by the description: the "weak light" model for cosmological redshifts. It has the immediate advantage that the same mechanism, the cumulative energy loss effect of the passage of photons through gravitational fields, could also explain anomalous redshifts for seemingly nearby quasars, since quasars are also associated with intense gravitational fields. More specifically, in the Weak Light model, we propose that the redshift of starlight from distant galaxies is produced by the same mechanism as that which produces gravitational redshifts. But it is the continuous background of a sea of gravitons which serves as a medium for light to propagate in, as well as giving rise to the force we call gravity in the vicinity of masses, which produces the redshift. So the properties of the Weak Light redshift include propagation delay, just as is true of gravitational redshifts, or of any wave propagating through a medium (i.e. refraction slows propagation). Indeed, in an infinite universe, there must be some such loss of energy by photons, forcing them out of the range of visible light. If there were not, then Olbers' Paradox would come into play: in an infinite universe, a line drawn in any direction would eventually intersect a star from which photons are emerging; hence the sky would be everywhere bright. The shift of photons out of the visible range through this "frictional" energy loss with the graviton sea can explain why the sky is dark; and it causes a redshift of the light of galaxies even without any expansion of the universe! It will eventually be possible to distinguish between the two possible causes of redshift: high velocity, in the Big Bang theory; or energy loss by passage through a refracting medium, in the Weak Light model. In the Big Bang theory, matter does not form into galaxies for about a billion years after the originating explosion, so there is a maximum possible redshift for the youngest galaxies we can ever observe. This maximum should occur at redshifts of about 50 or so. At longer wavelengths there should be few photons from the relatively cold gas which has not had time to form into stars and galaxies. Finally, the background spectral feature in the microwave region is the fireball remnant, with nothing observable except neutrinos expected beyond that. In the Weak Light model, there will be no such limit to the redshift of ordinary galaxies, which will be ever more abundant as one observes fainter and fainter, perhaps without limit. Galaxies with redshifts of 100 will eventually be found, then 1000, etc. H. The Microwave Blackbody Spectrum The spectrum of the cosmic microwave radiation has been determined to be quite close to that of a "blackbody", which is a type of spectrum requiring a fairly narrow source, such as the "surface" of a fireball remnant. So if the microwave radiation is indeed "background", i.e. coming from beyond the remotest galaxies, then it surely is what the Big Bang theoreticians have hypothesized: the remnant of a gigantic explosion involving much or all of the visible universe. But there is another possibility. Really, any fireball remnant which surrounds us would produce almost exactly the same type of spectrum. For example, if a supernova in our part of the galaxy exploded in the past, its fireball would eventually encompass us. Once inside of it, we would see a blackbody spectrum coming uniformly from all directions on the sky, which would inevitably cool to 2.78 degrees Kelvin at some time in its history. We would be virtually unable to tell the difference. The reason for the uniform appearance for an observer not near the center of the remnant may need some explanation. It is well known in physics that any inverse square field emanating from a spherical shell will produce a uniform effect everywhere inside the shell. (For example, the gravitational potential inside of a massive spherical shell is constant.) To see why, consider the radiation into a certain solid angle arriving at an observer at some distance inside the shell. The flux seen by the observer will vary inversely with the square of the distance; but the area of the shell emitting into that solid angle will increase with distance squared. The two effects exactly compensate, keeping the flux at the observer constant regardless of the distance to the shell wall. It follows that observers inside a fireball remnant would continue to be irradiated by it at some constant flux level no matter how large the fireball expanded, but for the fact that the fireball cools and gradually emits less flux with time. The distance of the microwave radiation is difficult to determine. But perhaps our new "COsmic Background Explorer" (COBE) satellite will find some evidence in mapping the microwave emissions from over the entire sky. For example, gravitational lensing effects might tend to brighten a background source in that direction. So if COBE sky maps trace outlines of bubbles and walls and other large scale features of the universe, the source must be more distant than those. On the other hand, if the maps have asymmetries similar to our own galaxy, that would argue strongly for a source related to our galaxy. Another good test of cosmologies is provided by the radio galaxies, whose space density seems to increase with distance. In the Weak Light model, distance is proportional to redshift, not to velocity. For example, at redshift z = 1, velocity = 0.6 c, and the distance is about 9 billion light years in the Big Bang theory; but the distance would be 15 billion light years (the Hubble radius) in the Weak Light model, which implies nearly five times the volume of space out to that distance. There is more volume in the Weak Light model corresponding to any given redshift, so the inferred densitias are less. As soon as we can observe and count the number of galaxies at large redshifts, we will be immediately able to distinguish between the two theories. We do have to be careful, though, that we use only cosmological redshifts in making such a comparison. Much evidence has accumulated in recent years that many quasars are not at the distances indicated by their redshifts. For example, many high-redshift quasars are associated with low- redshift galaxies. If the Weak Light model does not seem probable to the reader, he should at least appreciate how amazingly fragile is all of modern cosmological theory, based as it is on an assumption (that redshifts are due to velocities) whose rationale has since been severely undercut (some redshifts apparently are not due to velocities). The Big Bang theory, the physical limitation of the speed of light, the existence of "black holes" -- three fundamental tenets of present day cosmological research. There are reasons to believe that none of them is correct as customarily interpreted. We have also examined an alternative model which, at worst, has a comparable number of objections to it as the Big Bang theory, and perhaps fewer. But this model is deductive, not inductive. So it can be invalidated only by faulty reasoning or an incorrect starting point or assumptions. If it explains existing observations, provides insight and understanding, and predicts new things not previously known, I argue that is sufficient for it to be worthy of consideration AS A HYPOTHESIS in the field of astronomy. It should not be ignored that the model we have presented also offers an explanation of the how and why of the fundamental behavior of large scale processes in the universe, all in a single, coherent model. Separate AD HOC explanations are needed for many phenomena in the conventional models. ******** Clearly the same model could be extended to small scale phenomena as well. For example, why do photons and electrons behave as if they are particles when observed individually, and waves when observed collectively? The model suggests that they are pure transverse waves in a continuum; and that, when they encounter other substance, they THEN give the appearance of being particles. But that may be an illusion produced by interaction with the substance they encounter. The model provides such a new view of phenomena that all of quantum physics must be re-thought in this light. Since quantum physics already has reality paradoxes, a new way of interpreting its phenomena is at least timely, even if beyond the scope of this on-line course. Downloaded From P-80 Systems 304-744-2253


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