An important issue in science is what’s right and what’s wrong. Another is who gets credit for what. The former issue is scientific while the second is social. It matters little to the progress of science who discovers what. It matters a lot to the people who do it. We like to get credit where due.

Nowadays, Fritz Zwicky is often credited with the discovery of dark matter for his work on clusters of galaxies in the 1930s. Indeed, in his somewhat retrospective 1971 Catalogue of Selected Compact Galaxies and of Post-Eruptive Galaxies (CSCGPEG), he claims credit for discovering clusters themselves, which were

discovered by me but contested by masses of unbelievers, [who asserted] that there exist no bona fide clusters of stable or stationary clusters of galaxies.


Were Zwicky alive today, a case could be made that he deserves the Nobel Prize in physics for the discovery of dark matter. However, Zwicky was not the first or only person to infer the existence of dark matter early on. Jan Oort was concerned that dark mass was necessary to explain the accelerations of stars perpendicular to the plane of the Milky Way as early as 1932. Where Zwicky’s discrepancy was huge, over a factor of 100, Oort’s was a more modest factor of 2. Oort was taken seriously at the time while Zwicky was largely ignored.

The reasons for this difference in response are many and varied. I wasn’t around at the time, so I will refrain from speculating too much. But in many ways, this divide reflects the difference in cultures between physics and astronomy. Oort was thoroughly empirical and immaculately detailed in his observational work and conservative in its interpretation, deeply impressing his fellow astronomers. Zwicky was an outsider and self-described lone wolf, and may have come across as a wild-eyed crackpot. That he had good reason for that didn’t alter the perception. That he is now posthumously recognized as having been basically correct does nothing to aid him personally, only our memory of him.

Nowadays, nearly every physicist I hear talk about the subject credits Zwicky with the discovery of dark matter. When I mention Oort, most have never heard of him, and they rarely seem prepared to share the credit. This is how history gets rewritten, by oversimplification and omission: Oort goes unmentioned in the education of physicists, the omission gets promulgated by those who never heard of him, then it becomes fact since an omission so glaring cannot possibly be correct. I’m doing that myself here by omitting mention of Opik and perhaps others I haven’t heard of myself.

Zwicky got that treatment in real time, leading to some of the best published rants in all of science. I’ll let him speak for himself, quoting from the CSCGPEG. One of his great resentments was his exclusion from premiere observational facilities:

I myself was allowed the use of the 100-inch telescope only in 1948, after I was fifty years of age, and of the 200-inch telescope on Palomar Mountain only after I was 54 years old, although I had built and successfully operated the 18-inch Schmidt telescope in 1936, and had been professor of physics and of astrophysics at the California Institute of Technology since 1927 and 1942 respectively. 

Zwicky, in the introduction to the CSCGPEG

For reference, I have observed many hundreds of nights at various observatories. Only a handful of those nights have been in my fifties. Observing is mostly a young person’s occupation.

I do not know why Zwicky was excluded. Perhaps there is a book on the subject; there should be. Maybe it was personal, as he clearly suspects. Applying for telescope time can be highly competitive, even within one’s own institution, which hardly matters if it crossed departmental lines. Perhaps his proposals lacked grounding in the expectations of the field, or some intangible quality that made them less persuasive than those of his colleagues. Maybe he simply didn’t share their scientific language, a perpetual problem I see at the interface between physics and astronomy. Perhaps all these things contributed.

More amusing if inappropriate are his ad hominem attacks on individuals:

a shining example of a most deluded individual we need only quote the high pope of American Astronomy, one Henry Norris Russell…


or his more generalized condemnation of the entire field:

Today’s sycophants and plain thieves seem to be free, in American Astronomy in particular, to appropriate discoveries and inventions made by lone wolves and non-conformists, for whom there is never any appeal to the hierarchies and for whom even the public Press is closed, because of censoring committees within the scientific institutions.


or indeed, of human nature:

we note that again and again scientists and technical specialists arrive at stagnation points where they think they know it all.

Zwicky, CSCGPEG, emphasis his.

He’s not wrong.

I have heard Zwicky described as a “spherical bastard”: a bastard viewed from any angle. You can see why from these quotes. But you can also see why he might have felt this way. The CSCGPEG was published about 35 years after his pioneering work on clusters of galaxies. That’s a career-lifetime lacking recognition for what would now be consider Nobel prize worthy work. Dark matter would come to prominence in the following decade, by which time he was dead.

I have also heard that “spherical bastard” was a phrase invented by Zwicky to apply to others. I don’t know who was the bigger bastard, and I am reluctant to attribute his lack of popularity in his own day to his personality. The testimony I am aware of is mostly from those who disagreed with him, and may themselves have been spherical bastards. Indeed, I strongly suspect those who sing his praises most loudly now would have been among his greatest detractors had they been contemporaries.

I know from my own experience that people are lousy at distinguishing between a scientific hypothesis that they don’t like and the person who advocates it. Often they are willing and eager to attribute a difference in scientific judgement to a failure of character: “He disagrees with me, therefore he is a bastard.” Trash talk by mediocre wannabes is common, and slander works wonders to run down a reputation. I imagine Zwicky was a victim of this human failing.

Of course, the correctness of a scientific hypothesis has nothing to do with how likeable its proponents might be. Indeed, a true scientist has an obligation to speak the facts, even if they are unpopular, as Zwicky reminded us with a quote of his own in the preface to the CSCGPEG:

The more things change, the more they stay the same.

15 thoughts on “A few of Zwicky’s rants

  1. One day, maybe the psychologists will develop a model describing institutional paralysis. Though no one will think it applies to their fields. It’s pretty normal in politics and religion, though they function by manufacturing reality, not discovering it. Which is not supposed to be how science functions. Apparently it’s still conducted by humans though.
    Possibly a debate on how this particular dam breaks. Any guesses?
    Avi Loeb put up a fairly heretical essay on medium, that isn’t addressing the physics dilemma directly, but hints at it;
    View at
    The core paragraph;
    “Why do we favor most often the “flattering selection” method? Because it involves virtual realities that bring us pleasure. This is the basis for populist narratives in politics that appeal to the public and get leaders elected even though they reflect a virtual reality that does not exist. It also appears in spiritual congregations that advertise a virtual reality that fulfils an important emotional need for people who want to believe in it. And it also appears in mainstream theoretical physics — where some speculative theories, like the string theory landscape or the multiverse, require rare skills that allows individuals to demonstrate their mathematical virtuosity. By flattering the ego of their advocates, these theories obtain the mainstream status based on mathematical beauty — even when there is no empirical data to validate the notion that they describe reality. And without external constraints, it is always possible to add complexity them as in the case of epicycles for geocentric models in which the Earth was at the center of the solar system.”

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  2. Stacy, your humor is special…

    Giving Zwicky a Nobel for dark matter would be the second time the Nobel committee would give the physics prize to somebody for a mistaken experiment interpretation (after Fermi).

    We are in the strange situation that general relativity is correct at strong fields (as GTC-3 and double pulsars showed this month), but we do not know what happens at very weak fields.

    Dark matter, or MOND, or a combination of the two, or something entirely different: what will come out of all this?

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  3. Jocelyn Bell-Burnell in her Golden Webinar presentation makes the point that until Ryle and Hewish’s Nobel prize in 1974, there had not been any Nobel prizes awarded for discoveries in astronomy. Hannes Alfvén’s 1970 share of the prize for his explanation of the aurora as the interaction of charged particles from the Sun with the Earth’s magnetic field is probably the closest earlier prize award. Penzias and Wilson didn’t receive their Nobel prize until 1978. So, I think regardless of Zwicky’s (un)popularity in the astronomy community, it is unlikely that he would have received a Nobel Prize. After all Hubble and Lemaitre didn’t receive Nobel prizes either and one could argue that the discovery of the expanding universe was just as important as quantum mechanics at the time.


  4. Great photo of Zwicky! Better than the very popular image showing him as an unpleasant argumentative character (probably circulated by the people who called him a “spherical bastard”?)
    Zwicky also came up with another dangerous ‘unpopular idea’, but today it’s automatically banished to the memory hole by the priests and astronomers. If he were alive today any mention of ‘müdes Licht’ would mean the end of his career.

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  5. I agree with Johannes, suggesting Zwicky get the Nobel Prize for something that cannot be found is a good, if somewhat grim, joke.

    The situation is what it is. The good news is there are more and more critical comments arising both within and without the academic community where the problem resides. In intellectual terms theoretical physics has developed a guild like structure that holds two interlocking models of the microverse and macroverse to be absolutely and inviolably correct models of their respective domains.

    In academic terms, these two guilds, Quantum Mechanics and the Big Bang, control funding and publication for their respective disciplines. The guilds have a stranglehold on both the practical and intellectual components of doing theoretical physics.

    One approach might be to wrest control of the academic side, the funding and publishing realm, while simultaneously challenging the intellectual basses of the standard models. A two-front assault like that might work but it would take both willingness to undertake the effort, and some organizational skill. For starters, a meeting of like-minded individuals might be in order. Then do something.


  6. Matter consists of spin 1/2 particles. Radiation consists of spin 1 particles.

    Whoever uses the term “dark matter” has measured its spin and found 1/2.

    But somehow I cannot find any evidence for such a measurement.

    It seems to me, that “dark matter” is a misnomer.


    1. As someone whose knowledge of physics comes from trying not to get too hurt, too often, it’s occurred to me that synchronization is centripetal, while harmonization is centrifugal. When you get everything lined up, it’s concentrated, while when it balances out and fills the space, it’s distributed. So nodes and networks, organisms and ecosystems. Maybe particles and fields.
      Since one aspect of physics is waves, then when they synchronize, like a laser, it’s centripetal.
      Gravity is a centripetal effect, so could the relationship be reversed, that mass, this concentrated energy, is a consequence of the centripetal effect, of which gravity is one of its more physical expressions? Rather than gravity exclusively a property of mass.
      Then all the excess gravity is synchronization across the much broader spectrum of wave activity, where it’s not being distributed, but coalescing. Feedback loops.
      Galaxies shoot quasars out the poles, which would seem to be giant lasers.


  7. I am apologetic you are getting gibberish comments again. That can’t be fun for you. Or maybe it is.
    At least most of the comments seem to be on topic this time.

    Humans like simple narratives and not having to remember too much. So it’s natural for credit for discoveries to get compressed down to just one name even when they shouldn’t. This may be exasperating to one’s ego, but it’s better than evidence of something oddball going on getting ignored completely, at least.
    As you probably know, but some readers may not, there was an article about ‘Dark Matterless’ systems mentioning you in SA. I was happy to see both sides getting represented, as that doesn’t always happen:
    Readers who have already read several free articles may see it cut off partway..


  8. There are definitely parallels between the astronomical community in Zwicky’s time and today. I recall reading some derogatory comments about MOND in various places over the years. Though, in contrast to Zwicky, I don’t recall any harsh language used by Mordehai Milgrom against his critics, as he seems to maintain a civil discourse and avoids such polemics.

    The Scientific American article linked by Kirk M. was fascinating. There’s quite some consternation over the apparent absence of Dark Matter in the isolated, diffuse galaxy AGC 114905. I’m rather delighted with this as it dovetails with a concept I’ve been putting to paper.

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  9. I can’t help feeling that there is a philosophical problem here, rather than a scientific problem: scientists tend to classify ideas as “right” or “wrong”, whereas in real life we tend to classify ideas as “good” or “bad”. The latter approach allows us to classify things like dark matter in the category “it seemed like a good idea at the time” without the categorical classification as “wrong”. My research has always been, and continues to be, full of things that “seemed like a good idea at the time”. Progress occurs when such an idea no longer seems to be a good idea.


  10. Hi Stacy,
    Thank you for this post on “A few of Zwicky’s rants”.
    One obvious way that scientists give credit to others is in the Acknowledgements and References sections of their publications. For example, Acknowledgements takes care of crediting the builders of the telescopes & spectrographs used to make the observations that led to dark matter – no one expects these people to be credited with the discovery of dark matter. And References takes care of giving credit to the work of previous researchers. (I notice that the majority of the references in CSCGPEG are to other Zwicky publications.) I haven’t looked at Vera Rubin’s publications but wonder whether she ever mentioned Zwicky or Oort. Of course, Zwicky is dead and cannot defend himself, nor can he be held responsible for the continuing claims by others that he discovered dark matter.
    For me the biggest crime is when one scientist takes the credit for the work of another. Fortunately, this is pretty rare in science. But unfortunately, it seems to be the norm in politics.

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  11. Hi everyone. Thanks for your comments. Two observations in response: one, there are certainly analogies between Zwicky and people today. In this regard, it is problematic to be too far ahead of one’s time. Even if essentially right, it isn’t recognized if no one else grasps its importance. Second, with regards to Nobel prizes, there ought to be a lot for this subject already, regardless of where the final answer lies. Arguably, both Oort and Zwicky deserved one for discovering the effects we currently attribute to dark matter. But that interpretation is what is fraught; the observational evidence is not – and it is the experimental discovery of new things that the prize was meant to recognize, not theories or interpretations – Einstein won his for the photoelectric effect, not the theory of relativity. Unfortunately, dark matter has become such a broad, blanket term that it has become a catch-all for all sorts of work that should be recognized independently – even absent a clear interpretation. Instead, Rubin (and others) was not awarded a prize in part because Zwicky had already discovered dark matter. But what they did was very different – Zwicky found that the velocity dispersions of galaxy clusters could not be explained without something extra. Rubin and Bosma (and Robertson and Shostak) showed that rotation curves were flat – and importantly, Rubin & Bosma showed that this was persistently the rule. This is now a de facto law of nature – that ought to warrant a Nobel prize by itself. Tully & Fisher discovered their eponymous relation, which is another law of nature. Milgrom identified a new constant of nature, a0. That warrants a prize even if MOND is wrong – it did for Lambda! I could go on, but our obsession with the dark matter interpretation has blinded us to the important data-based discoveries that led to it.

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