Supernovae and Pulsars
The principal feature that makes M 87 a particularly attractive subject for investigation, the fact that it is close enough to enable recognition of details that are lost at the greater distances, is even more pronounced in the case of our own Milky Way galaxy. Of course, our galaxy is not a giant elliptical, or even a Seyfert spiral, but it is after all, a reasonably big and reasonably old galaxy. Such a galaxy clearly must have accumulated some of the relatively old stars that are scattered around so profusely by the galactic explosions. As time goes on, one after another of these old stars will reach the age limit and explode, even while the galaxy as a whole is well below the normal limiting age. We have already found that a star which reaches the lower explosive limit (in efEect a temperature limit) explodes and produces a phenomenon that we have identified as a supernova. If we call this a Type A stellar explosion, then we can express the new conclusion that we have reached through a consideration of the probability of the presence of some very old stars in the younger galaxies by stating that in these galaxies there must also exist Type B stellar explosions that have some quite different characteristics because they occur at the age limit rather than at the temperature limit.
In the terminology of the astronomers, any full-scale explosion of a star is a supernova, and the foregoing statement therefore asserts that there are two distinct types of supernovae. The existence of two different types of these events has already been recognized observationally, and this fact is sufficient in itself to demonstrate the validity of the theoretical conclusion. We have deduced theoretically that there are two different types of stellar explosions; the observations confirm the deduction by disclosing that supernovae exist in two different types.
So far in this work we have used the term supernova only with reference to the Type A explosions, those that occur when stars reach the lower explosive limit, and whatever has been said as to the nature of these events and their products applies specifically to Type A. Throughout the discussion in the final chapters of this volume, however, it has been emphasized that the basic energy sources underlying the quasars and all associated phenomena are the explosions of stars that reach the upper destructive limit: the Type B explosions. At this point we need to recognize that the explosions of this second type are similar enough to those of Type A in their general nature and in their products that they also appear to observation as supernovae, and the available observational data therefore include some information on Type B events. Here, then, we have an opportunity to extend our inquiry to an examination of this important class of explosions in an evironment where they can be observed individually.
Unfortunately, these observations of the individual events can only be made under some rather severe handicaps. No observable supernova has occurred in our galaxy for nearly 400 years, and information about the active stage of these explosions can be obtained only from extragalactic observation, aside from such deductions as can be made from imprecise eyewitness accounts by observers of the supernovae of 1604 and earlier. Our most significant information comes from examination of the characteristics of certain astronomical objects, a few of which are known to be remnants of old supernovae and others that are similar enough to justify including them in the same category. Even at best, however, the hard evidence is scarce, and it is not surprising that there is considerable difference of opinion among the astronomers as to classification and other issues. For this reason our deductions from theory conflict with some current thought, but there is a rather general correspondence between the theoretical products of our Type A explosions and the astronomers Type I supernovae; likewise between the theoretical products of our Type B explosions and the astronomers Type II supernovae. For purposes of the subsequent discussion we will therefore equate A and B with I and II respectively.
The Type A explosion is a single event which theoretically originates from a hot, massive star at the upper end of the main sequence, a member of a group of practically identical objects. All Type I supernovae are therefore very much alike. As expressed by R. Minkowski, one of the leading investigators of these events, The Type I supernovae form a very homogeneous group.56 Current astronomical opinion regards the Type II supernovae as the ones that originate from the hot, massive stars, but this opinion is based on theory, not on observation, and our theory simply arrives at a different conclusion. The magnitude of the Type I supernova at the peak is relatively high, and the decay rate in the early stages is relatively low, but the overall life as compared to that of a Type II supernova is nevertheless short, for reasons which we will discuss later. The Type I supernovae are widely distributed among the various types of galaxies, as they occur, or at least may occur, fairly early in the life of the stars that are involved. This is another point of conflict with current thought, or more accurately, it is another aspect of the same conflict, as the current view of the supernova distribution is based on the identification of the hot, massive stars with Type II rather than Type I. This leads to confusion, as can be seen when Minkowski says that the Type II supernovae are the ones that occur in the Population I stars of the spiral arms, while at the same time he identifies all of the historical supernovae in the salar neighborhood (in a spiral arm of our galaxy) , other than the Crab Nebula, as belonging to Type I.57 In the context of the Reciprocal System of theory, the hot, massive Population I stars are highly evolved first generation objects (stars which have not yet passed through the supernova stage) . The stars that produce Type II supernovae are either much older unevolved first generation stars or members of later generations.
The Type I supernovae do not actually enter into the subject matter of the present discussion of the quasar class of phenomena, except through their association with the Type II objects, and we will therefore turn our attention to the latter, commenting further on the characteristics of Type I only where a comparison with these objects is of assistance in clarifying the Type II picture. Aside from the previously mentioned fact that it occurs much later in the life span of the star-at the very end-the most distinctive feature of the Type B explosion is that it generates enough energy to give the explosion products the speed that is required in order to carry them beyond the neutral point and into the region of motion in threedimensional time.
The total mass participating in this explosion may be either greater or less than that of the kind of a star that becomes a Type I supernova, as the Type II event may involve anything from a single dwarf star to a whole n-generation stellar system of six or eight units. But the Type B explosion converts a much larger percentage of this mass into energy, and the ratio of energy to unconverted mass is therefore considerably higher, producing a much greater average particle speed, and thereby increasing the proportion of the total mass going into the high speed explosion product. The Type B explosion also has the character of radioactivity, in that the initial outburst does not complete the action, but is succeeded by a period of gradually decreasing activity extending over a long period of time. The optical emission from a supernova comes mainly from the slow speed component of the explosion products, the material expanding outward in space, and since the amount of this material is much smaller in the Type II events, the optical magnitude of the Type II supernova at the peak is considerably less than that of the average Type I event, despite the greater total energy release in Type II. A recent investigation arrived at average magnitudes of -18.6 for Type I and -16.5 for Type II.58 The emission from Type II also drops off more rapidly at first than that from Type I, and the light curves of the two types of explosions are thus quite different. This is one of the major criteria by which the observational distinction between the two types is drawn. For example, Minkowski remarks in one case that The supernova was visible for more than 1 year. This excludes Type II.59
In view of the limited optical activity and the relatively small mass of the remnants, there has been some question as to what happens to the energy of these Type II events. Poveda and Voltjer, for instance, comment that they find it difficult to reconcile current ideas as to the energy release in the Type II supernovae with the present state of the remnants.60 This question is answered by our finding that the great bulk of the energy that is generated goes into the ultra high speed explosion products.
The radio emission is more representative of the true energy situation. Here we have to depend on observations of the remnants of old supernovae, but the results of the radio measurements on these objects are definite and unequivocal. For example, there is a nebulosity in the constellation Cygnus, known as the Cygnus Loop, which is generally conceded to be a remnant of a Type II supernova, and is estimated to be about 60,000 years old. After all of this very long time has elapsed, we are still receiving almost twice as much radiation at 400 MHz (in the radio range) from this remnant as from the remnants of all three of the historical (1006, 1572, 1604) type I supernovae combined.57
There are a number of other remnants with radio emission that is far above anything that can be correlated with Type I, including Cassiopeia A, the most intense radio source known; IC 443, which is similar to the Cygnus Loop and almost as old, and three remnants in the Large Magellanic Cloud, the strongest of which is reported to have about 200 times the emitted radio power of the Cygnus Loop.57 Likewise there are remnants whose radio emission is within the range of the Type I products, but whose physical condition indicates an age far beyond the Type I limit. These must also be assigned to Type II. In general, it seems safe to say that unless there is some evidence of comparatively recent origin, aIl remnants with measurable radio emission can be identified with Type II supernovae, even though Type I events may be more frequent in our gaIaxy.
This conclusion enables us to classify the Crab Nebula definitely as a Type II product. The radio flux from this remnant of a supernova observed in 1054 A.D. is about 50 times that of the remnant of the Type I supernova that appeared in 1006 and is therefore of practically the same age.57 The Crab Nebula was originally assigned to Type I by the astronomers, mainly on the basis of differences between it and Cassiopeia A, which was regarded as the prototype of the Type II remnant, but more recently it has been recognized that the differences between this nebula and the Type I remnants are much more pronounced. Minkowski (1968) concludes that an unbiased assessment of the evidence leads to the conclusion that the Crab Nebula is not a remnant of a supernova of Type I.57
The greater and longer-lasting radio emission of the Type II supernovae is, of course, consistent with the theoretical results of the greater total energy and the continuing character of the Type II events. Another observational confirmation of the theoretical explanation of the long time scale of Type II comes from evidence of further explosive events subsequent to the original outburst of the supernova. A current explanation of the peculiar features of Cassiopeia A attributes them to the presence of two distinct shells of expanding material. The Crab Nebula is likewise made up of two dissimilar components. Examination of the spectra of extragalactic supernovae also lends considerable support to the double shell hypothesis. The presence of multiple absorption lines in the spectra of many supernovae of Type II suggests that more than one shell has been ejected. (Minkowski) 57
It thus appears altogether possible that the A.D. 1054 supernova and the latest outburst of Cassiopeia A may have been preceded by other major explosive events in the same stars. This suggestion becomes all the more plausible when it is realized that many of the stars involved in Type II supernovae are actually star systems double or multiple stars. Both, or all, of the stars in such a system have the same chronological age, but variations in the conditions of existence can very well introduce some differences in the evolutionary age, and hence there may be a substantial interval between the explosions of the components of a multiple star.
This possibility of multiple explosions would also explain what has been a puzzling feature of Cassiopeia A. Expansion with high velocity clearly indicates that the nebulosity is the remnant of a supernova of moderate age, but no outburst in its position has been recorded.57 Even a small supernova would have been a target of intense interest at the time calculated for this event, about 1700 A.D., and the idea that an event powerful enough to produce the strongest radio source in the heavens could have passed unnoticed seems preposterous. But if there was already a strong source of optical radiation at this location, one that had originated from previous outbursts, and the supernova of 1700 A.D. did not increase the optical radiation by any striking amount, there is a good possibility that it might have escaped detection. A Type I supernova could hardly have been missed, even under these conditions, but in view of the much lower optical emission from Type II and the faster decay, this explanation is at least plausible. The increase in radio emission would have been immense, but it meant nothing at that time.
In addition to the main outburst or outbursts which constitute the principal feature of the Type II supernova, there is a long-continued supplementary generation of energy as the explosion gradually spreads through additional portions of the affected mass. This continuing action is manifested by the persistence of the radio emission, and by the evidence of energetic events within the remnants. For instance, the optical remnant of Cassiopeia A is undergoing rapid changes,61 while the Crab Nebula, another remnant, contains some formations which are highly variable in appearance and brightness and which move quite rapidly.62 Calculations alsa indicate that an input of energy into this nebula of the order 1038 erg/sec is required to sustain the observed emission.57 The current suggestion is that this energy is injected into the nebula from the central star, but the ultra high speed product emits only a relatively small amount of energy, and therefore cannot be the source of the continuing supply. The supplementary energy has to come from radioactivity within the material ejected in the primary outburst. It is the existence of this secondary energy generation in the Type II supernovae, but not in Type I, that accounts for the great difference between the maximum 165 period of observable radio emission in Type I remnants, perhaps 3000 years, and that in Type II remnants, which we can estimate at more than 100,000 years. This is somewhat similar to the difEerence that we noted between the Class II quasars, which have secondary energy generation and therefore maintain their emission for a billion years or more, and the Class I quasars, that have only the energy with which they were ejected from the galaxy of origin, and therefore fade out after a hundred million years or so.
The same factors that are responsible for the differences between the relatively slow speed products of the two types of supernovae-the remnants-also result in some significant differences between the ultra high speed products of the two kinds of events. Here, again, the general nature of the corresponding products is the same. Just as the slower component in each case is a cloud of dust and gas particles moving outward in space, so the high speed component in each case is a cloud of dust and gas particles moving outward in time. But the greater intensity and other special characteristics of the Type B explosions have some effects that make the behavior pattern of the Type B high speed component significantly different from that of its Type A counterpart, the white dwarf star.
It was mentioned previously that the compact cores of some of the larger galaxies are quite similar to the white dwarf stars in their general aspects. In both cases the constituent units, stars in the core and particles in the white dwarf, are moving with ultra high speeds in a confined space, with the result that additional time is being introduced between the units of matter and the properties of the material aggregate are altered accordingly. Such a galactic core is therefore a giant version of the white dwarf star-a white dwarf core, as we called it earlier-differing only in the nature of the fast-moving units. Similarly, we can regard the ultra high speed product of a Type B explosion as a miniature version of the quasar, as here again the essential difference is merely that the constituent units of the quasar are stars whereas those of the Type B explosion product are particles of dust and gas.
As in the case of the quasar, the energy imparted to the particles of the high speed Type B product is sufficient to carry them past the neutral point and into the region of motion in three-dimensional time. Ultimately, therefore, they will disappear from the material region of the universe, but before they can do this, they, like the quasars, must first overcome gravitation. Compared with the quasar situation, however, the gravitational effects on the supernova particles are minuscule, and the visible results are consequently quite different. The quasar is composed mainly of material particles that are individually moving with speeds less than that of light (even though the aggregates of these particles, stars, are moving at ultra high speeds) , together with fast-moving particles that are spatially confined. The visibility limit for this kind of material is a function of the spatial distance, and the quasar therefore remains as a visible object out to its overall limit of 2.00 even though the gravitational effect in the dimension of the explosion speed is eliminated at a quasar distance of 1.00. However, the ultra high speed particles produced by the Type II supernovae are not spatially confined, and their radiation is invisible beyond a distance of 1.00 in the explosion dimension.
As explained in Ghapter VI, there is a gravitational limit for each aggregate of matter within which the gravitational motion exceeds the progression, and beyond which the progression is the greater. For a star similar to the sun this limit is a little over two light years. Outside the limit the gravitational effect continues to decrease with increasing distance in accordance with the inverse square law, until at another limiting distance the entire mass exerts only one unit of force; that is, it exerts the same gravitational force that one unit of mass exerts at one unit of distance. Inasmuch as fractional units do not exist, there is no gravitational effect at all beyond this outer limit, which is about 13,000 light years for a star of one solar mass. The ultra high speed particles produced by the Type II supernova are traveling at unit speed in the explosion dimension, and their maximum period of visibility is therefore approximately 13,000 years.
In the discussion of the spatial speed of the quasar it was pointed out that only that portion of the explosion speed that is applied to overcoming gravitation has any effect on motion in space, and consequently, the faster the quasar travels the less spatial distance it moves. For instance, at the point where gravitation is down to .500, half of the 1.00 explosion speed causes movement in space, and the other half, the net outward speed, does not. The same principle also applies to radiation. At this same .500 distance, half of the radiation from the ultra high speed explosion product is observable in space and the other half is unobservable. But there are no fractional units, and during each unit of time the radiation must be either spatial or non-spatial; it cannot be divided between the two. Hence the reduction in the spatial radiation below the level of one unit of radiation per unit of time takes place in the number of units of timeduring which the radiation appears in space; that is, the radiation is intermittent.
At .500, alternate units are spatial. The natural unit of time has been evaluated in previous publications as .152 x 10-15 seconds. We thus receive radiation for this length of time, after which there is a quiet interval of .152 x 10-15 seconds, then another flash of radiation, and so on. Obviously an alternation at such extremely short intervals cannot be distinguished from continuous emission, but as the high speed explosion product moves outward the ratio of spatially active to spatially inactive units of time decreases, and when the age of this product begins to approach the 13,000 year limit the ratio becomes small enough to make the periodicity evident. Under these conditions the radiation is received as a succession of pulses. For this reason the observed ultra high speed product of the Type II supernova is known as a pulsar.
Approximately 60 pulsars have been located since the first of these objects was discovered in 1967, and it appears that this number includes most of those within range of the available facilities. According to Hewish, it does not seem likely that the number will increase significantly until new radio telescopes of greater collecting area are available.34 The distribution and observed properties of these objects have been interpreted as indicating that they are situated within the galaxy and at distances mainly within 2 or 3 Kpc. This is consistent with the theoretical conclusion that they are products of Type II supernovae. Furthermore, two of the pulsars have been definitely identified with supernova remnants, and A. J. R. Prentice has found somewhat less conclusive evidence of correlations with four more. He summarizes his report in these words, I present evidence that most pulsars may have been formed in Type II supernova explosions and initially possessed extremely high velocities, of order 1000 km s-1.63 The theoretical points of similarity between the pulsar and the quasar have also been recognized observationally. P. Morrison asserts that Quasi-stellar radio sources are analogous to pulsars in every respect save that of scale,64 and he suggests that quasars are simply giant pulsars. The situation as we find it theoretically is somewhat more complicated than this, but as a first approximation the statement is correct.
Like their Type I counterparts, the pulsars may accrete material from their surroundings and become visible as white dwarf stars. The conditions are unfavorable for such accretion, however, because of the short lifetime of these objects and the limited amount of slow speed material available for capture, and so far only one such star has been definitely located. This is the star associated with the pulsar in the Crab Nebula, where the environment seems to be quite unusual, perhaps, as suggested previously, because of an earlier explosion at the same location. The relatively low polarization of the radiation from the Crab Nebula pulsar, contrasted with the complete polarization of that from PSR 0833, the next youngest of these objects, is indicative of a significant environmental difference. Inasmuch as the pulsar radiation emanates almost entirely from particles of matter moving at ultra high speeds it is almost completely polarized on emission, and a lower polarization measurement can be taken as evidence of depolarization.
A large amount of effort has been devoted to a search for white dwarfs in the pulsar positions because of the relevance of this information to the theories which picture the pulsars as white dwarfs existing under some special conditions, and the failure ta detect them optically despite careful searches34 has weighed heavily against the white dwarf theories. Our findings are that the pulsars may assume the white dwarf status, but in most cases will not, and the lack of success in these searches is not surprising. The most likely prospects for optical detection would seem to be those pulsars in which the polarization is relatively low. PSR 0833, which has been one of the principal targets of the search, is probably one of the least likely to be emitting any significant amount of optical radiation.
From the explanation of the origin of the pulsars given in the foregoing paragraphs it is evident that the pulsation periods must be increasing at a measurable rate. Here, again, the observations confirm the theoretical conclusion. The periods of all pulsars thus far studied are systematically increasing,34 says Hewish. Since the decrease starts from the gravitational limit in all cases and follows a fixed mathematical pattern, the period of a pulsar is an indication of its age, and this correlation provides a means whereby we can arrive at some conclusions concerning the time scale of these objects.
The individual pulsar time scales will vary to some extent
because they are based on the gravitational limits. and these limits are
dependent on the stellar masses involved, but we may establish some values
on the basis of the solar mass, as an indication of the general situation.
Initially, the exploding star is outside the gravitational limit of its
nearest neighbor, and the gravitational restraint on the pulsar is mainly
due to the slow-moving remnants of the explosion. This effect decreases
rapidly, however, and within a short time the gravi-
At the gravitational limit the radiation is continuous; that is, radiation is received during 6.6 X 1015 units of time in every second. But in 900 years the pulsar, traveling at the speed of light in the explosion dimension, has moved out to a distance of 900 light years in this dimension (a distance analogous to the quasar distance of the earlier discussion) , and by reason of the attenuation of the gravitational force the radiation has been reduced to the point where it is only being received 30 times per second. The ratio of this pulsation period to the initial period is 2.2 X 1014, and the corresponding distance ratio, by reason of the inverse square relation, is the square root of this value, or 1.5 X 107. Dividing 900 years by 1.5 X 107 we obtain 6 X 10-5 light years as the effective gravitational limit. This means that at this distance, about 500 times the stellar diameter, the sum of the gravitational effects of the neighboring star and the remnants of the supernova is equal ta the space-time progression, and the radiation is still continuous. Beyond this point there is a pulsation with an increasing period.
Looking now in the other direction from the reference pulsar, toward objects of greater age, PSR 0833, the second youngest of the pulsars now known, has a period of .089 seconds, which corresponds to an age of 1470 years. This pulsar is therefore nearly 600 years older than the one in the Crab Nebula. The longest period thus far discovered is 3.475 seconds, which indicates an age of 900 years. Some still longer periods are possible before the ultimate limit of about 13,000 years is reached, but these long period pulsars will probably be faint and difficult to detect. An interesting subject for investigation is the pulsar that should theoretically exist in the supernova remnant Cassiopeia A. If this supernova occurred only 300 years ago, as the motions of the remnants indicate, these remnants should contain a pulsar with a period only one-ninth that of the pulsar in the Crab Nebula. This is 270 pulses per second, which will no doubt be difficult to detect, but not necessarily impossible.
A study of the indicated age distribution of the 50 pulsars listed in the article by Hewish in the 1970 Annual Review of Astronomy and Astrophysics discloses a rather unexpected situation. On the basis of the theoretical relation between period and age, these pulsars are distributed through an age range of at least 10,000 years. During 6000 years of this total, the first 4500 and the most recent 1500, only 6 pulsars appeared, an average of one every 1000 years. But in the intervening 4000 years 44 pulsars made their appearance, one in every 100 years. Furthermore, the rate of formation did not build up gradually to a peak and then decrease slowly, as might be expected; it rose quite suddenly, held nearly constant during the 4000 year interval, and then dropped almost as suddenly as it rose.
This seemingly anomalous distribution over the period of time involved may help to provide an explanation of the otherwise excessive number of pulsars. A rate of one per hundred years in a small section of one galaxy is clearly inconsistent with current estimates of the average number of Type II supernovae, which are in the range of one per several hundred years for an entire galaxy. However, we have already noted that a galaxy contains many clusters of stars of approximately the same age, and the large number of pulsars originating during the 4000 year period could be the result of a whole cluster of 40 stars reaching the destructive limit almost simultaneously.
Even on this basis, the indicated production of pulsars seems excessive for a region with a radius of only about 3 Kpc, and it may be advisable to give further consideration to the possibility that the pulsars may actually be located at considerably greater distances than those now accepted. Energy considerations, for example, will be favorable to a substantial increase in the distance scale when the twodimensional nature of the radiation from the pulsars is taken into account. However, it may not be necessary to take up all of the existing discrepancy by a decrease in the pulsar density, as the information now available regarding the relatively low visibility of the Type II supernovae suggests that the estimates of the rate of occurrence of these supernovae in the external galaxies are too low. There may well be many extragalactic equivalents of Cassiopeia A: supernovae that have come and gone unnoticed. But in any event, the number of pulsars now known would seem to be more consistent with a distribution over a substantially greater volume.
Indeed, there would seem to be adequate grounds for suspecting that the observed pulsars are distributed throughout the greater part of the galaxy. On this basis, the strong concentration of these objects toward the galactic plane, which is now unexplained, would be consistent with a fairly uniform distribution of the pulsars among the galactic stars, a result that we would naturally expect from the mixing action due to the motion of the galaxy.
As matters now stand, there are no available observational data of sufficient accuracy to enable making an independent check of the pulsar distribution in volume. A comparison of the estimated valumetric concentration of these objects with the corresponding values for the white dwarfs will, however, serve as a rough check on the figure of 13,000 years which we have established as the approximate life period of a pulsar. At first glance this figure seems extremely low in view of the fact that most stages of stellar existence extend into the billion year range, but when we compare the relative space densities of the two classes of objects we find that the life of the pulsars must necessarily be very short. The number of stars in the nearby regions of the galaxy is estimated at about one per 10 cubic parsecs, and about three percent of these are thought to be white dwarfs. The number of white dwarfs per cubic parsec on this basis is .003. Present estimates of the space density of the pulsars lead to a figure of 5 X 10-8 per cubic parsec.34 If we accept the current opinion that the total number of supernovae is divided about equally between the two types, the life periods of the two ultra high speed explosion products are proportional to their space densities.
Multiplying the 13,000 year life of the pulsar by this density ratio, 6 X 104, we arrive at 8 X 108, or approximately one billion years, as the life period of a white dwarf. This figure is probably somewhat low, as the indications are that the number of white dwarfs is currently underestimated, whereas, as we have noted, the space density of the pulsars is probably overestimated, but at any rate, the calculation shaws that the 13,000 year pulsar life is consistent with a billion year life span for the white dwarf.
There is some divergence between the measured rates of increase of the pulsation periods and the theoretical rates corresponding to the respective periods, but they are probably within the range of deviations that can be expected by reason of internal activity within the pulsars. Internal motion can either add to ar subtract from the normal rate of increase of the period, even to the extent, in some cases, of converting the increase into a decrease for a limited time. Sudden changes have been reported from both of the two youngest pulsars, NP 0532 and PSR 0833.
In addition to the internal motions, there may be a rotation of the pulsar as a whole, and the fine structure of the pulses is a reflection of these two factors. The so-called drifting or marching sub pulses, for example, are quite obviously effects of local motions in the pulsar that are being carried across the line of sight by the pulsar rotation. The presence or absence of accreted slow speed material may also have a significant effect. In PSR 0833, for instance, where the 100 percent polarization indicates little or no accretion, there is also little or no fine structure,34 whereas the other young pulsar, NP 0532 in the Crab Nebula, has both a substantial amount of accreted material and a complex pulse substructure.
Of course, most of the figures that we have used in the foregoing discussion of the pulsars are merely rough approximations-aside from the measured pulsation periods, almost any value quoted may be in error by a factor of 3 or 4-but they fit together closely enough to show that the pulsar theory derived from the concept of a universe of motion produces results that are consistent with what little is known about these objects. To the extent that confirmation is possible under the existing circumstances, therefore, this confirms the assertions of the theory that the pulsars are short-lived, ultra high speed products of Type II supernovae.
It is ironical, says Antony Hewish, that astronomys latest discovery, the pulsars, should have been stumbled on unexpectedly during an investigation of quasars, those starlike radio sources whose origin is still one of the outstanding problems of astrophysics.65 But contrary to the implication in this statement, the discovery of the pulsars does not generate a new problem for physical science. The existence of these objects is simply another aspect of the same problem, and when the correct basic theory is applied to the situation, all aspects of this problem-pulsars, quasars, white dwarfs, galactic explosions, and so on-are cleared up in one operation.
The foregoing pages have accomplished their defined objective by deriving a consistent and comprehensive theory of the pulsars, quasars, and associated phenomena, and confirming its validity by extensive qualitative and quantitative evidence. Once it becomes possible to summon enough scientific courage to discard the now untenable concept of a universe of matter, on which all of the hard-pressed traditional theories are based, and to replace it with the concept of a universe in which the basic entities are units of motion, the existence of quasars is one of the inevitable consequences. It has taken a great many pages ta trace the chain of reasoning all the way from the basic concept to the quasar, but this is only because of the amount of attention that has had to be given to the details. The essential elements of the theoretical development are simple, both logically and mathematically.
But it is appropriate to emphasize that this is not just a theory of the quasars and their associates; it is a general theory of the physical universe, one that is applicable to all physical phenomena, and it applies the same principles and relations to astronomical phenomena, including the quasars and the pulsars, that are utilized in dealing with the properties of matter, the behavior of electricity and magnetism, or any other physical entities or relations. The theory was not constructed for the purpose of explaining the quasars; it was in existence years before the quasars were discovered, and no additions were necessary to bring the quasar phenomena within its scope. All that had to be done was to carry the chain of reasoning a little farther in some areas.
Furthermore, the theory employs none of the far-fetched ad hoc assumptions that conventional theories find it necessary to utilize even to get a start toward an explanation of the quasar phenomena-such things as neutron stars, black holes, gravitational collapse, quarks, and the like: fanciful concepts that have no observational support whatever and are simply drawn out of thin air. Indeed , the new theory makes no assumptions at all, other than the assumptions as to the nature of space and time which constitute the basic postulates of the system. Nor does it draw anything from experience. Quasars, pulsars-even matter and radiation-appear in the theory not because they are known from observation, but because they are necessary consequences of the theory itself. The existence of each of these entities is deduced from the postulated properties of space and time without introducing anything from any other source.
Finally, it is worthy of note that the new system of theory achieves a high degree of economy of thought. The same explanations that account for the peculiar characteristics of the white dwarf stars also account for the similar characteristics of the quasars, the Seyfert galaxies, and other objects of this type. The same energy sources that produce the great galactic explosions also account for the energy emission from the radio galaxies, for the Type II supernovae, and for the large energy output from the quasars. The same factor that accounts for the nature of the motion imparted to the quasar by the primary galactic explosion also accounts for the relation of the quasar magnitude to distance, for the absence of blueshifts, and for the polarization, not only of the quasar radiation but also that of the pulsars.
The ability of the new theoretical system to provide a comprehensive and detailed explanation of these quasar phenomena with which conventional theory is completely unable to cope is a graphic illustration of the benefits that can be gained by replacing the present multitude of different parts and pieces that do not fit together very well with a solidly based and fully integrated theory from which such phenomena as the galactic explosions, the recession, the pulsars, the quasars, the elementary particles, and the other items with which the astronomers and the physicists are now having trouble, emerge as essential features of the main line of theoretical development, rather than having to be forced into the theoretical structure by all sorts of questionable expedients.
By this time it should be clear that the traditional physical theories based on the concept of a universe of matter have reached the end of the road; that a continuation of the heroic efforts that are being made to patch the holes and to bolster the elements of the theoretical structure that are failing under the load is no longer justified. After all, there are limits to what can be built on a false foundation, even with the benefit of all of the ad hoc assumptions, principles of impotence, and other ingenious devices that the modern scientist utilizes to evade contradictions and inconsistencies and to reinforce the weak spots in his arguments. As the continuing improvement in observational facilities enables penetrating deeper into the far-out regions of the universe, the never-ending task of revising and reconstructing existing theories to conform to the new knowledge becomes progressively more difficult.
The astronomers, who are dealing with physical phenomena on a gigantic scale, are acutely conscious of the awkward situation in which they are placed by the lack of any basic theoretical structure that is applicable to their new discoveries.
Total inadequacy is a harsh term, but it is fully justified under the circumstances, and in calling for a radical revision of the laws of physics to meet present-day needs Hoyle is on solid ground. The physicists cannot deny the need for such changes, as they freely concede that they are encountering equally serious difficulties along the outer boundaries of their own fields, as well as in some of the most basic areas. What we badly need is a greater synthesis, says Abraham Pais, at the same time admitting that this may lead us to revise very basic concepts.67 Sir Harrie Massey states the case in these words:
But this big theoretical advance is not something that we must await. It is already here; all that is now necessary is to recognize it. As the earlier pages of this volume and its predecessors have shown, the essential requirement is a realization that the universe which science is attempting to understand is a universe of motion, not a universe of matter. Once this understanding is achieved, and the logical consequences thereof are followed up in detail, the physicists will have the clarification for which they are asking, and the astronomers will have the revised physical laws that will enable them to bring all of the phenomena of the very large and the very fast within the scope of theoretical understanding in the same manner in which the mystery which has heretofore surrounded the quasars and their associates has been swept aside in this work.