In the preceding pages we have seen that a Type II supernova in the outer regions of the galaxy, originating from a relatively large star, produces a pulsar that moves away from the explosion site at ultra high speed, and also an assortment of products of smaller sizes and lower speeds, both above and below unit speed (the speed of light). We have also seen that when large numbers of these supernova explosions occur in the interiors of the oldest and largest galaxies (as most of them do, since the oldest stars are concentrated in the central regions of these galaxies), the pressure that is built up by the fast moving explosion products ultimately blows out a section of the overlying layers of the galaxy. This fragment them moves off at ultra high speed as a quasar. Now we will want to give some consideration to the events that precede this ejection.
The fact that the energy of each of the major explosive events comes from an accumulation of relatively small (compared to the final energy release) energy increments contributed by explosions of individual stars not only establishes the normal pre-quasar pattern, but also determines the kind of variations from the normal pattern that are possible. Since any small galaxy, or even a globular cluster, may incorporate a few remnants of disintegrated old galaxies, Type II supernovae may occur in any aggregate, but they are relatively rare in the small young structures, and most of their products escape immediately from these structures. However, when a galaxy reaches the stage in which some of its constituent stars other than the strays begin to arrive at their age limits, the number of supernovae in the galactic interiors, where the oldest stars are concentrated, increases dramatically. Coincident with the increase in age, a galaxy also increases in size, and the interior regions in which the explosive activity is taking place are enclosed by a continually growing wall of overlying matter. In the ordinary course of events this growth leads the increase in internal activity by a sufficient margin to prevent the escape of any large amount of explosion products until the quasar stage is reached. The normal pre-quasar period is therefore characterized by a slow, but steady, build-up of intermediate and ultra high speed matter in the galactic interiors.
With the possible exception of one class of galaxies that we will consider shortly, the galaxies of the normal evolutionary sequence, those that will eventually eject quasars if they are not captured by larger aggregates before they reach the critical age, show no structural evidence of the activity that we find from theory is taking place in their interiors. There are, however, two observable phenomena that indicate the existence and magnitude of this activity. One of these is radio emission. The magnitude of the radiation at radio frequencies indicates the rate at which isotopic adjustments are taking place in matter recently accelerated to speeds greater than unity by the supernova explosions. It has been shown by Fanti et al. , that the amount of radio emission is related to the brightness, and hence to the size, of both spiral and elliptical galaxies, as the theory requires.271 All of the more advanced spirals are radio emitters, and the giant spheroidal galaxies are strong radio emitters.
Further evidence of the presence of upper range speeds in the galactic interiors is provided by the high density that is characteristic of the central cores of the larger galaxies. According to current estimates, the density in the core of our Milky Way galaxy is 30 or 40 times as great as would normally be expected, while the central regions of M 87, the nearest, and consequently the best known of the giants, are estimated to be at least 80 times the normal density. Current efforts to explain these abnormal densities are based on the assumption that there must be a large number of high density objects in these central regions: white dwarfs, or the hypothetical neutron stars or black holes.
The development of the theory of the universe of motion now reveals that the extremely high density of all of the compact astronomical objects-white dwarf stars, pulsars, x-ray emitters, galactic cores, quasars, etc.-is due to the same cause: speeds in excess of unity (the speed of light). The conventional explanation of the high density of the white dwarfs is based on the idea of a “collapse” of the atomic structure, and it therefore cannot be extended to an aggregate composed of stars. The effect of upper range speeds, on the other hand, is independent of the nature of the moving entities. The reduction in the effective distance between objects by reason of these speeds is a specific function of the speed, irrespective of whether these objects are atoms or stars.
Thus, the high density of the central regions of the larger galaxies is not due to the presence of unusual concentrations of very dense objects, but to the distortion of the scale of the reference system that results from the high speeds of the normal constituents of the galactic interiors. The cores of these galaxies are in the same physical condition as the white dwarf stars and the quasars; that is, their density is abnormally high because introduction of the time displacement of the upper range speeds has reduced the equivalent space occupied by the central portions of the galaxies. In brief, we may say that the reason for the abnormal density in the older and larger galaxies is that these galaxies have white dwarf cores-not white dwarfs in the core, but cores in which the constituent stars and particles are in the same condition as the constituent particles of a white dwarf star.
We do not have enough information to enable tracing the build-up of the internal activity of the galaxies from its beginning, but we do have some knowledge about the interior of a galaxy that is not yet very far along this road. This is our own Milky Way galaxy, where we have the advantage of proximity, and can observe details that would otherwise be beyond the scope of our instruments. A small region, known as Sagittarius A, apparently located at the dynamic center of the galaxy, has some unusual characteristics which indicate that it is the kind of a core that we could expect in a spiral of moderate age. The picture is not entirely clear as yet, but as one report puts it, “Radio observations indicate that something quite unusual is going on at the center of our own galaxy.”231 Another observer draws the same conclusion from the infrared emission which, he says, is “so intense that it cannot easily be interpreted unless we believe that something very special is occurring there.”272
Here we have another instance of the association of strong radio and strong infrared emission that was discussed in Chapter 14, an association that the astronomers have never been able to explain. Referring particularly to the quasars, Shipman calls this “the infrared puzzle.”273 Both of these types of radiation are characteristic of matter that is moving at upper range speeds. Their existence in the core of the Milky Way galaxy shows that this galaxy has already developed the kind of an intermediate speed core-a white dwarf core -that we would theoretically expect in a galaxy of this size and age.
The optical radiation from the core is unobservable because of absorption in the intervening matter, but some information as to the size and properties of this core has been derived from infrared and radio measurements. It is generally assumed that the radiation at about two microns wavelength is thermal, and that its intensity is proportional to the star density. As indicated in Chapter 14, our findings are in agreement with this conclusion. On this basis it is estimated that there are about 70 million solar masses within 10 parsecs of the center of the core, and that the density in the innermost volume of 0.1 parsec radius is 100 million times the star density in the vicinity of the sun.274 On first consideration such a concentration may seem incredibly large, but when it is realized that this observed high spatial density is actually a very low density in time, it becomes evident that the observed magnitude is not out of line with other limiting densities. For instance, the density of solid matter at zero temperature and pressure is in the neighborhood of 100 million times the density of the most diffuse stars.275
The radiation in the near infrared comes from stars that are moving at upper range speeds (which accounts for their high spatial density), but are composed of particles whose speeds (temperatures) are in the range below unity (which accounts for the thermal character of the radiation). In addition to this type of radiation, there is also a very intense radiation in the far infrared, a non-thermal radiation that “is presumed to be synchrotron radiation.”276 In the light of the findings detailed in the preceding pages, it is evident that this presumption is incorrect, and that the non-thermal radiation, both the infrared and the associated radio emission, originates from isotopic adjustments in matter that has been accelerated to upper range speeds. The existence of radiation of this nature identifies the Milky Way galaxy as one that has a good start toward the build-up of matter with speeds in the upper ranges which will eventually lead to the kind of a gigantic explosion that ejects a quasar. “Astronomers,” says Hartmann, “are still groping for explanations of what is happening at the center of the Milky Way.”277 Here is the framework of the explanation that they are looking for.
As noted earlier, the evidence of internal activity increases as the galaxy becomes older and larger. We are not yet able to make a quantitative determination of the maximum size from theoretical premises, but we know from theory that such a limit exists, and this is confirmed by observation. Fred Hoyle points out that “Galaxies apparently exist up to a certain limit and not beyond.”278 Rogstad and Ekers give us an idea as to the location of that “certain limit.” They report that an absolute photographic magnitude of about -20 is a necessary condition for a spheroidal galaxy to be a strong radio source.279
Some of the giant galaxies that are in the neighborhood of this limiting size have jets of high speed material issuing from their central regions. The nature and properties of these jets were examined in Chapter 26. Our present concern is with their origin. Such a jet is a conspicuous feature of the giant galaxy M 87. Like the quasar 3C 273, with which it is associated, M 87 is of special interest because it is the only member of its class near enough to be accessible to detailed investigation. This object has all of the features that theoretically distinguish a galaxy that has reached the end of the road. It is a giant spheroidal, with the greatest mass of any galaxy for which a reasonably good estimate can be made; it is an intense radio source, one of the first extragalactic sources to be identified; and a jet of high speed material emitting strongly polarized light can be seen originating from the interior of the galaxy. These indications of explosive activity are so evident that they were recognized in the original application of the Reciprocal System of theory to the astronomical field, just as soon as the theoretical limits to the life of the galaxies were discovered, long before any observational evidence of galactic explosions was recognized by the astronomers. The 1959 publication contained this statement: “It would be in order to identify this galaxy [M 87], at least tentatively, as one which is now undergoing a cosmic explosion.”
Jets such as that issuing from M 87 are obviously produced under conditions in which pressure is released in a specific direction. Since the galactic explosion that produces a quasar blows out a particular segment of the outer structure of the galaxy, the spatial motion of the quasar is given such a direction. Similar conditions may exist where fragmentary material is ejected, and in that event the initial ejection takes the form of a jet. The observable astronomical jets are fast-moving streams of unconsolidated material with individual speeds (temperatures) that extend into the upper ranges. On this basis they should theoretically be strong emitters of radiation at radio wavelengths, particularly at the ends of the jets, and the radiation should be highly polarized. These deductions, based on the theoretical relations developed in the earlier pages, are in agreement with the observations.
The theoretical development likewise accounts for a remarkable feature of the jets that is inexplicable in the context of current astronomical theory. This is the nearly uniform thickness of the M 87 jet and others of a similar nature. The hypothesis that the astronomers have invoked to account for the radio emission and the polarization would result in a rather rapid expansion and dissipation of the jet. Why does this not occur is, to them, a mystery. Simon Mitton makes this comment:
The thickness of the jet is only tens of light years, so there must be a powerful constraint to the natural expansion of the gas.280
The development of the theory of the universe of motion identifies this “powerful constraint.” Aside from some entrained low speed matter, the constituents of these jets are atoms and particles moving at speeds in the two upper ranges. At these speeds the cloud of particles that constitutes the jet is expanding into time, rather than into space, and its spatial dimensions are decreasing slightly, rather than increasing.
The available evidence does not indicate specifically how the jet originated. It is possible that the hole in the outer structure of the galaxy through which the material of the jet is issuing may be the result of a collision similar to that which seems to have taken place in NGC 5128 and some other radio galaxies. However, the relatively small cross-section of the jet and the absence of any indication of major distortion of the galactic structure suggest that the jet is more likely to be an after-effect of the ejection of a quasar or other explosion product. It no doubt takes an appreciable time to close the opening left by the ejection of a section of the outer wall of the galaxy, and during this interval there must be some loss of energetic material from the interior. If this is a correct interpretation of the situation, the leakage now visible as a jet will eventually terminate as the outer wall of the galaxy reforms and closes the existing gap.
There is at least one quasar in the immediate vicinity that could have been ejected from M 87 recently. According to Arp, the average recession speeds of the galaxies in different parts of the region around M 87 range from about 400 km/sec more than the speed of M 87 to about 400 km/sec less.244 Any quasar or radio galaxy whose normal recession is within about 0.0015 of the recession of M 87 is therefore a probable member of the cluster of galaxies centered around M 87, and is a possible product of an explosion of that galaxy. Included within these limits is a quasar, PKS 1217+02, with a redshift of 0.240, which is equivalent to a recession shift of 0.0045 (almost the same as that of M 87). There are also several radio galaxies in the same neighborhood, with redshifts that qualify them as possible partners of this quasar. It thus appears likely that PKS 1217+02 and one of the nearby galaxies, perhaps 3C 270, with redshift 0.0037, were ejected in a relatively recent explosion.
Of course, it is not possible to reconstruct the exact sequence of events in this crowded area where there are so many galaxies that are interacting with each other, but it is clear that the whole range of explosion products is present, from the very old Class II quasar, 3C 273, to the jet of M 87, which originated only yesterday, astronomically speaking. There may even have been an explosion of M 87 that did not produce a quasar. It has been noted that the galaxy M 84 (radio source 3C 272.1) is aligned with the M 87 jet in such a manner as to suggest that this galaxy may have been formed from material ejected in a more violent period of the activity of the galaxy that preceded the production of the jet.281 The present activity of M 87 could well be the concluding phase of that explosive event.
Ultimately, after a number of ejections have occurred, an exploding galaxy will have lost so much of its substance that it will be unable to resume its normal shape and once more confine the explosion products to the interior of the structure. Thereafter the pressures necessary for the ejection of fragments of the galaxy will not be generated, and the products of the supernova explosions will be expelled at more moderate speeds in the form of clouds of dust and gas. The galaxy M 82, the first in which definite evidence of an explosion was recognized, seems to be in this stage. Photographs of the galaxy taken with the 200-inch Palomar telescope show immense clouds of material moving outward, and the galactic structure appears badly distorted.282
Just how large M 82 may have been in its prime, before it began ejecting mass, cannot be determined from observation, but presumably it was in the giant class. At present it is in the range of the spirals. Sooner or later the remnants of all such overage galaxies will be gathered into their younger and larger neighbors. The eventual fate of M 82 is clearly foreshadowed by a comment in an article by A. R. Sandage that the evidence of explosive events in this galaxy was discovered in a survey of “a group of visible galaxies centered on the giant spiral galaxy M 81.”282 Capture of one after another of this group of galaxies will eventually build M 81 up to the maximum size. The giant thus produced will then continue on its way to the ultimate destruction that it, in turn, will experience, leaving behind remnants that will be incorporated into the new galaxies that form in the regions of space that are vacated.
Identification of the galaxies that, like M 82, are in the process of disintegration, is complicated by the fact that galaxies in the process of consolidation display many of the same features. A collection of galaxies with these features, an “Atlas of Peculiar Galaxies,” compiled by Halton Arp, probably contains a mixture of both types. The galactic combinations should outnumber the disintegrations by a rather wide margin, since many combinations are required to produce one giant spheroidal candidate for disintegration.
Before turning to another subject, it may be of interest to note that the astronomers have been so frustrated in their attempts to understand M 82 as an exploding galaxy that they are now shifting to other ideas in the hope of getting something that they can fit into the prevailing structure of astronomical theory. The following is a recent statement by Harwit:
- The brightest far-infrared extragalactic source known (M 82) at one time was thought to be an exploding galaxy because hydrogen is seen streaming out of its central portions at velocities of 1,000 kilometers a second. Energetic processes that we do not yet understand appear to be active in this galaxy.
This is a good example of the operation of one of the policies that has taken modern astronomical theory out of the real world and into the land of fantasy. M 82 exhibits some of the characteristic features of an exploding object. Recognition of these features naturally led at first to the conclusion that an explosion was in process in the interior of the galaxy. But as more information has been accumulated, difficulties have been experienced in reconciling this information with current theories as to the nature of such an explosion. As Harwit reports, the situation is not understood. The rather obvious implication of these difficulties is that the current astronomical theories, insofar was they apply to the M 82 situation, are wrong, but rather than pursuing this line of thought the theorists have chosen to develop some new hypotheses to replace the explosion assumption-hypotheses that are more speculative and less subject to disproof by testing against observation. The present-day tendency toward this kind of a retreat from reality will be given some further consideration in the next chapter.
Another kind of galactic phenomenon results from what we may call premature explosive activity. A galaxy may, for example, capture a number of relatively old stars quite early in its life, or it may even pick up some old star clusters or a remnant of a disintegrated galaxy. These older stars will reach their age limits and explode before the galaxy arrives at the stage where such explosions are normal events. If the premature activity of this nature is not extensive, the energy that is released is absorbed in the normal motions of the galaxy. But where a considerable number of stars-those in a captured cluster, for instance-reach the age limit in advance of the normal time, some significant results may follow.
If large scale activity of this kind begins when the galaxy is in an earlier stage in which it is smaller and less compact than the giant spheroidals, the concentration of explosion products in the interior may break though the overlying material before the pressure required for the ejection of a quasar is attained. The theoretical results of this kind of a situation are observed in a class of objects first identified and described by Carl Seyfert, and known as Seyfert galaxies. These are spiral galaxies, much smaller than the giant spheroidals, and by reason of their spiral structure, in which much of the mass is spread out in the form of a disk, their central regions are relatively exposed, rather than being buried under the outlying portions of the galaxies, as in the giants. The action that is going on in the Seyferts is thus more accessible to observation.
Present-day astronomical theory is totally unable to account for the observed properties of these galaxies. With reference to the facts that are now known about them, D. W. Weedman makes the comment that “The reason for their existence remains one of the most pressing astronomical mysteries. ”284 As in so many of the “mysteries” examined in the preceding pages, however, these observations are readily explained in the context of the universe of motion. The biggest enigma for the astronomers is the magnitude of the energy emission. Radiation of the upper range types-radio and far infrared-is being emitted from these Seyfert galaxies in the same manner as from the core of the Milky Way galaxy, but at an immensely greater rate. As reported by Neugebauer and Becklin:
The amount of power such galaxies radiate in the infrared corresponds to as much as 1011 times the power output of the sun. This is approximately the amount of power radiated by all the stars in our galaxy at all wavelengths.168
“Conventional concepts of nuclear physics are woefully inadequate in accounting for such a large energy output from such a miniscule region,”285 says Mitton. The astronomers’ perplexity is still more vividly expressed in this statement:
- One cannot help wondering what strange machine is hidden at the center of that galaxy [NGC 1275, a Seyfert] and others similar to it. Such prodigious emission of energy and matter from a region that appears to be shrinking, the more we study it, poses questions to which we have no answers. (P. Maffei)
Now that we have established the nature of the quasars, the finding that the Seyferts are premature quasars identifies the source of the energy, and eliminates the problem of the size of the emitting region. This region appears small only if we look at it as a spatial domain, which it is not. It is actually a large region containing a huge number of stars, but its extension is in time, rather than in space.
The violent motion required by the theory of the universe of motion has been detected in the cores of these Seyfert galaxies. R. J. Weymann reports that the emission spectra of the Seyfert galaxies “indicate that the gases in them are in a high state of excitation and are traveling at high speeds in clouds or filaments. Outbursts probably occur from time to time, producing new high-velocity material.” This, of course, is a description of the state of affairs that the theory says should exist, not only in the Seyfert galaxies, but in the cores of the giant spheroidals as well. To the astronomers the whole situation is a “puzzle” because, unlike the Reciprocal System, conventional astronomical theory provides no means, other than gravitation, of confining high-speed material within a galaxy, and gravitational forces are hopelessly inadequate in this case. Weymann summarizes the situation in this manner:
- If we accept the fact that the gas inside the tiny core of a Seyfert galaxy is moving at the high apparent velocity indicated by the spectra, and if we assume that the gas is not held within the core by gravitation, we must explain how it is replaced or conclude that the violent activity observed in the core is a rare transient event caused by some explosive outburst.
But the latter possibility, he concedes, is inadmissible, because the Seyfert galaxies “cannot be considered particularly rare.” Hence this piece of observational evidence that is such a significant and valuable item of confirmation of the theory described in this work, not only the theory of the Seyfert galaxies, but the whole theory of the galactic explosion phenomena, including the quasars, is nothing but another enigma to conventional theory.
Weymann also points out that the spectral characteristics of the light from the nuclei of these Seyfert galaxies are quite different from those of the light coming from the outlying regions.
- Ordinary stars (such as our sun) emit more yellow light than blue light. This is also the case if one observes a Seyfert galaxy through an aperture that admits most of the light from the galaxy. As the aperture is reduced to accept light only from the central regions, however, the ultraviolet and blue part of the spectrum begins to predominate.
This is another piece of information that fits neatly into the general theoretical picture. We have deduced from theory that the predominantly yellow light (positive U-B) that we receive from ordinary galaxies is characteristic of matter moving with speeds less than that of light, while the predominantly ultraviolet light (negative U-B) is characteristic of matter moving with upper range speeds. Now we observe an otherwise normal galaxy with a nucleus in which there is some unusual activity. From theoretical considerations we identify this activity as being due to a series of supernova explosions that are accelerating some particles or aggregates of matter to speeds in excess of the speed of light, and we find that the light from this galaxy displays just the characteristics that the theory requires.
The existence of some kind of an unidentified energetic process in the interiors of the Seyferts—a “strange machine,” as Maffei called it in the statement previously quoted—is generally recognized. Simon Mitton makes this comment:
- The variations in NGC 1068 (a Seyfert galaxyJ require a non-thermal mechanism for the generating source of the intense infrared emission… Because of the difficulties with the hot dust concept, Rieke and Low prefer to attribute the radiation to a mysterious non-thermal source.
As reported by Mitton, it is now generally agreed that there is sufficient evidence to show that there are “periodic explosions in the Seyfert nucleus that blast debris into the surrounding regions.” But these explosions are unexplained in current astronomical thought. “All models of Seyfert nuclei ultimately rely on the ad hoc existence of a primary energy source”285
The theory developed herein resolves all of these issues. Furthermore, it explains the periodic nature of the explosive activity. This is one of the most difficult aspects of the situation from the standpoint of current theory. Observations confirm the existence of high speed matter in the interiors of the Seyfert galaxies in the intervals between explosions, but, as pointed out by Weymann, conventional astronomical theory has no way of explaining the build-up and containment of this very energetic material. In this case, as in so many others, the Reciprocal System, by providing an explanation, is filling a conceptual vacuum.
The same factor that makes the internal activity of the Seyfert galaxies more accessible to observation than that of the giant spheroidals, the thinner layers of overlying material, also limits the kind of products that can result from this activity. In these smaller galaxies it is not possible to build up the great concentration of energy that is necessary in order to eject a quasar, and the emissions of material therefore take less energetic forms. The most common result is nothing more than an outflow of matter in an irregular pattern, but in some instances small fragments of the galaxy are ejected, without the ultra high speed of the quasar.
Because of the periodicity of the explosive events in the Seyfert galaxies the nature and magnitude of the radiation from the products are variable. Immediately after an outburst the galaxy is a strong radio and infrared emitter, as noted in Chapter 18. As time goes on, the isotopic adjustments are completed and this radiation therefore decreases. As a result, the radio emission from some of the Seyferts is little, if any, greater than that from the average spiral galaxy. Except for that portion which is entrained in the outgoing low speed matter, the intermediate speed products of the explosion remain in the immediate vicinity of the galaxy because of the absence of translational motion in space in the intermediate speed range. Ultimately this material cools enough to drop back below the unit speed level. This initiates isotopic adjustments of the inverse nature, producing x-rays. Thus some Seyferts are strong x-ray emitters, while in others little or no x-ray radiation is detected,264 depending on the stage in which the galaxy happens to be when observed. As would be expected, the stronger sources, both radio and x-ray, are subject to large variations.
It is quite evident that there is some kind of a connection between the Seyferts and the quasars. As expressed by Weymann, “Except for an apparent difference in luminosity, Seyfert galaxies and quasars represent essentially similar phenomena.”231 Many astronomers believe that quasars are simply distant Seyfert galaxies, the basis for such a conclusion being the finding that a number of quasars are surrounded by diffuse matter that has the same redshift as the quasar itself.
It is difficult, however, to see why this conclusion should necessarily follow from the observed facts. Some of the reports specify that what has been observed is “nebulosity” that presumably indicates the presence of hot gas. But the presence of hot gas surrounding an object does not preclude that object from being a quasar. Indeed, our findings with respect to the origin of the quasars indicate that they must be surrounded by hot gas in their early stages, and probably are in their later stages as well. Nor is the hypothesis as to the identity of the Seyferts and the quasars entitled to any more credence because an association has been found between a quasar and a galaxy of the same redshift. The logical conclusion in this case is that the previous classification was in error, and that the observed object is actually a Seyfert galaxy.
The Seyferts are difficult to identify at great distances because the cores are so much more luminous than the surrounding structure. lt can be expected, therefore, that improvements in instrumentation and procedures will result in identifying an increasing number of objects of this type among the distant objects now classified as quasars. Only a small proportion of the spiral galaxies have thus far been recognized as Seyferts. Weedman estimates about one percent.284 Even a substantial increase over this percentage would be consistent with the theoretical status of the Seyferts as deviants from the normal evolutionary pattern, the pattern that culminates in the production of quasars.
The analog of the Seyfert galaxy is not the quasar but the giant spheroidal galaxy from which the quasar was ejected. Both of these types of galaxies are subject to periodic outbursts in which quantities of dust, gas, and galactic fragments are ejected. But the giant galaxy also ejects quasars and diffuse material at ultra high speeds, while the Seyfert explosions are not powerful enough to accelerate any of their products into the ultra high range. Consequently there are no counterparts of the quasars in the Seyfert products. Nor do these products have any of the other ultra high speed properties, such as the characteristic radio structure.
- No Seyfert galaxy exhibits a double radio structure such as that found in most radio galaxies and quasars. (P. Maffei).
To conclude the discussion of the pre-quasar situation, we turn now to the earliest ancestors of the giant galaxies that produce the quasars, the globular clusters. The general run of stars of these clusters are far too young to become supernovae, but as emphasized in the earlier pages, the dispersed material from which the globular clusters were formed contained a few remnants of disintegrated galaxies-stars and small star clusters. These are incorporated into the newly formed globular clusters, usually serving as nuclei for the cluster formation. They are already well along the way to their limiting age, and may reach it while the cluster is still an independent unit.
In a large cluster, one that has not yet undergone the attrition that takes place in the immediate vicinity of a galaxy, the amount of material overlying the central regions is sufficient to withstand a considerable amount of internal pressure. Any ultra high speed explosion products probably escape, but those that are moving at less than unit speed are largely confined, while the intermediate speed products, aside from those that are entrained in the outward-moving material, remain at the location of origin, inasmuch as they have no spatial motion components. The presence of these intermediate speed products results in the existence of a high density region in the center of the cluster, a small-scale replica of those in the cores of the large galaxies. After the few very old stars are gone there is no replacement of the energy lost from the explosion products, and their temperature therefore decreases. At some point it drops below the unit level. This initiates x-ray emission.
A 1977 publication reported that seven “x-ray stars” had been found in the globular clusters of our galaxy.288 Unlike the returning white dwarfs, whose x-ray emission is observable only when the material from the interiors of these stars breaks through the overlying low speed matter in a nova explosion, these “x-ray stars” are actually concentrations of explosion products similar to those in the observable supernova remnants, and they continue their emission in the manner of those remnants, gradually decreasing as the isotopic adjustments are completed.