MARTIN GARDNER Notes of a Fringe -Watcher

The Anomalies of Chip Arp

We have watched the farther galaxies I don't know what the 'C stands for, but fleeing away from us, wild herds of panic all his friends call him 'Chip.' He's in horses—or a trick of distance deceived danger of losing all those friends, if he the prism. . . . keeps up what he's doing now! "Now mind you, I am kidding, be­ —Robinson Jeffers cause I am very fond of Chip Arp. In fact, we were graduate students at Caltech N HIS SPLENDID book The Drama together. But in those years he was nice." I of the Universe (1978) the late George An astronomer at Hale Observatories, Abell, an astronomer who served on the in California, Chip Arp is still adding to editorial board of this magazine, specu­ his collection of crazy objects, and still lates what generates the enormous ener­ making sharp rapier jabs at his more gies emitted by quasars (quasi-stellar orthodox colleagues. (Actual sword fenc­ sources). Quasars are almost surely the ing, by the way, is one of his major hob­ most distant known objects in the uni­ bies.) Like Thomas Gold, the subject of verse. Their gigantic redshifts indicate this column two issues back, Arp is a that some are moving outward at veloci­ competent, well-informed scientist who ties close to 90 percent of the speed of delights in the role of gadfly. His peculiar light. They occupy positions believed to anomalies are quasars that seem to be be very near the "edge" of the light connected by bridges of luminous gas barrier, a boundary beyond which noth­ but that have markedly different red- ing could ever be observed from our shifts, or high-redshift quasars that ap­ galaxy. pear joined to low-redshift galaxies. "All these ideas," writes Abell, re­ "Arpian objects" they are sometimes ferring to alternative theories about the called. If such objects really are con­ nature of quasars, "and many more (ex­ nected, they cast grave doubts on the cept, probably, the right one), have been establishment view that a redshift is an suggested. . . . But I must say, the situa­ accurate indicator of a quasar's distance tion isn't helped any by certain catalogs and receding speed. of crazy-looking objects. One nasty per­ Of course no one can be absolutely son who has given us such a catalog, and sure that the orthodox view is correct— who keeps adding to it, is Halton C. Arp. in science you can't be certain of any-

236 THE SKEPTICAL INQUIRER, Vol. 11 thing—but powerful arguments support shifting is caused not by receding velocity it. The redshift is a "Doppler" effect but by what is called the "gravitational similar to changes in the pitch of sound redshift" of relativity theory. Strong from objects moving rapidly toward or gravity fields jog light toward the red. away from you. Light from objects mov­ Judging by closer stellar objects, gravita­ ing away has its wavelength shifted to tional redshifts are too weak to account the red side of the spectrum; light going for quasar redshifting even if there are in the opposite direction is blueshifted. massive black holes at their centers, as The effect is strongly confirmed by the many cosmologists suspect. Arp's view is motions of nearby stars and galaxies for that nobody knows what quasars are or which there are other ways to estimate what causes their redshifts. He believes distances and velocities, but for quasars the quasars are nearby and that his the redshift is the only way to gauge anomalies prove that their redshifts are distances and speeds. Could the shift have not proportional to their distances or causes other than outward motion? velocities. One theory, for which there is not a Arp's opponents, the majority of shred of evidence, is the old "tired light" astrophysicists, think his peculiar objects hypothesis of Fritz Zwicky. This proposes with their "discordant redshifts" are that, when light travels long distances nothing more than optical illusions. If through space, something not yet under­ you look long and hard enough at the stood makes it shift toward the red. Very heavens, they say, you can expect to find few astronomers support this conjecture, many spots where one quasar seems although it is periodically revived with linked to another, or to a galaxy, when new and exotic explanations of what actually one object is millions of light- causes the light to alter. years in front of or behind the other. The Another strongly discredited theory situation is like searching for peculiar is that the quasars are indeed moving patterns in a table of random numbers. rapidly away from us but are objects You are sure to find unusual patterns ejected violently from our galaxy. This that, after you apply a posteriori statis­ could give them huge redshifts, but allow tics, seem highly unlikely. Arp and his them to be nearby rather than extremely supporters claim he has found more far away. Such a "local theory" of quasars anomalies than chance can explain. Op­ is held by a minority of astrophysicists ponents insist that his statistics are faulty. who simply can't believe that quasars If he is right, cosmology will be in a near the rim of the universe could shambles. generate enough energy to be as bright As a science writer with only a dim as they are. grasp of astrophysics, I would bet against If quasars are ejected from our galaxy, high odds that Arp is wrong. "The people one would expect similar stellar objects who were antagonistic toward Arp in the to be blown out from other galaxies, and past," said astronomer Wallace Sargent, those moving toward us would be blue- "have been afraid that he might be right. shifted. No blueshifted quasar has yet They're not, for the most part, afraid been seen. Proponents of the local theory anymore. He's like a pebble in your shoe. argue that blueshifts move the spectrum After a while you don't notice the irrita­ into the ultraviolet, where the radiation tion anymore."* is harder to detect than that shifted into On the other hand, it has always been the infrared. Maybe blueshifted quasars are out there. We just haven't found them. •As quoted in "The Most Feared Astronomer A third conjecture, allowing quasars on Earth: Hallon C. Arp," by William Kauf- to be nearby, is that most of their red- mann HI. Science Digest. July 1981.

Spring 1987 237 hazardous to be certain about cosmo- Hoyle, incidentally, in the first edition of logical theories, and today may be no the same book, who invented the term exception. If, for example, it is discovered "big bang." He intended it as a phrase of that photons (carriers of light) have a derision. "When we look at our own slight rest mass, quasar redshifting could galaxy," he wrote, "there is not the small­ indicate high temperatures rather than est sign that such an explosion occurred." high velocities. In addition, collisions of Other famous cosmologists have been such photons with the black-body radia­ just as dogmatic as Hoyle—and just as tion that permeates the universe (a rem­ mistaken—about their theories of the nant of the primeval explosion) might origin of the universe or the origin of also shift quasar light toward the red. our solar system. However, from my It has been said that cosmologists, novice's seat, it now looks as if big-bang more than most scientists, incline toward theory will last 500 years and that Arp's dogmatic rhetoric. Here, for instance, is anomalies will prove to be just what his Fred Hoyle defending his once-popular opponents say they are—perspective il­ steady-state theory in the 1960 revision lusions. "Call halton eatwords," wrote of The Nature of the Universe: "Is it likely James Joyce in Finnegans Wake (page that any astonishing developments are 569). Let Abell have the final comment: lying in wait for us? Is it possible that cosmology of 500 years hence will extend It is always the unexplained phenomena as far beyond our present beliefs as our and the observations we do not under­ cosmology goes beyond that of Newton? stand that lead us to new insights about It may surprise you to hear that I doubt the nature of the physical world. Most whether this will be so." of us strongly expect that when we know enough, we shall be able to understand Five years later, it was Hoyle who quasars and other peculiar galaxies in was surprised. That was when two teams terms of known laws of physics. But of New Jersey scientists, working inde­ consider the delight of the scientist when pendently, found the microwave radiation he finds something really new, and you that can be plausibly explained only as a will realize why many of us, deep inside, residue of the ancient fireball. It was hope not. •

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238 THE SKEPTICAL INQUIRER, Vol. 11