Knut Lundmark and the Forgotten Dark Matter Discovery
Table of Contents
Background: textbook accounts
Look in your standard cosmology textbook (in my case, the closest one at hand is Barbara Ryden’s Introduction to Cosmology) and go to the section that describes the experimental discovery of dark matter. Two of the things you will likely find in there are the following pieces of information:
Historical observations: Zwicky and Rubin
- The virial theorem was applied to the Coma cluster by Fritz Zwicky in 1933. In the paper “Die Rotverschiebung von extragalaktischen Nebeln”,Ā Helvetica Physica ActaĀ 6: 110ā127 (1933), Zwicky studied the motion of galaxies in the Coma cluster and concluded that they were moving too fast to be bound together unless there was a large amount of unseen matter in the cluster adding to its gravitational strength. Zwicky named this matter “Dunkle Materie” or, literally translated, “Dark Matter”.
- Zwicky’s work on dark matter did not have a very large scientific impact until 1970 when Vera Rubin studied the rotational curve of the Andromeda galaxy, “Rotation of the Andromeda Nebula from a Spectroscopic Survey of Emission Regions”, Astrophys.J. 159: 379 (1970), that the dark matter story really began. Just like Zwicky had discovered that the Coma cluster would need a significant amount of invisible matter to hold together, Rubin found that the stars in the Andromeda galaxy were moving too fast to be gravitationally bound unless thereĀ was a large amount of dark matter.
Knut Lundmark: the forgotten contributor
The history of the discovery of dark matter, therefore, seems rather set in stone, Zwicky was the first to discover it in 1933 and it gained traction after the work of Rubin in 1970. However, there is one person who has been forgotten in this storyline, Professor Knut Lundmark. Apart from discovering the expansion of the Universe before Edwin Hubble (NatureĀ 490,Ā 176Ā (2012)),
it turns out that Lundmark also had a thing or two to say about dark matter, something which would be forgotten, left to collect dust in a drawer, rediscovered by someone else, and only 85 years later found again.
1930 conference and Lundmark’s findings
In a conference celebrating the 40th anniversary of the German Astronomical Society in 1930, Lundmark presented his findings on the velocities of stars within galaxies. Sounds familiar? It should. What Lundmark had done was essential to measure the galaxy rotation curves of several different galaxies and compare the mass required to the luminous mass of the galaxies. His conclusion was the same as that of Rubin 40 years later, a large part of the mass of a galaxy is in a form that is not visible to us. Like Zwicky would do three years later, Lundmark spoke about this additional mass as “Dunkle Materie” although he never went as far as suggesting that it would be a new form of matter, only that it was a matter which we could not see. Lundmark’s findings were published in Lund Medd.Ā 125, 1Ā (1930) and subsequently seems to have been largely forgotten.
Rediscovery in 2015
The rest, as they say, is history. With Zwicky’s and Rubin’s results becoming highly popular and the essential foundation for our modern understanding of dark matter, Lundmark’s work was not rediscovered until 2015. On April 17 of that year, Lars Bergstrƶm, professor in theoretical physics at Stockholm University, gave a presentation at a conference in Trieste, Italy, where he told the story of how he had stumbled upon the reference to Lundmark’s work.
Conclusion
As to the sens moral of the story, dark matter was eventually discovered, but it is not always the first person to discover something that history will credit.
Professor in theoretical astroparticle physics. He did his thesis on phenomenological neutrino physics and is currently also working with different aspects of dark matter as well as physics beyond the Standard Model. Author of “Mathematical Methods for Physics and Engineering” (see Insight “The Birth of a Textbook”). A member at Physics Forums since 2014.
“From a hard scientific point of view, no. For how we look at the achievement of historical figures, in particular in connection with science, it plays a very important role. Certainly someone would have discovered relativity even if Einstein had never existed, yet here we are a hundred years later making T-shirts with his face on them..”
I’m afraid we rarely appreciate the achievements reached before the famous breakthroughs.
The then new born heroes are hailed and often to the oblivion of the shoulders of those they stand on.
I regularly hear the phrase “the time was there” in historic documentations but not what or who made it ripe.
To many famous (in its popular meaning) scientists I associate a counterpart who’s been at the same point of insight but less commonly known:
Galilei – Kopernikus, Newton – Leibniz, Curie – Meitner, etc. And those are only pairs of which their second part is at least famous to scientists.
Maybe we should start a separate thread to worship scientists the history seemingly has forgotten although they have been pioneers to the glory of others.
“On the other hand, I’m sure that Vera Rubin should get the Nobel for her work on the rotation curves of galaxies. I guess, however, she’ll have to wait until it’s clarified what dark matter is, i.e., the earliest when dark-matter candidate particles are discovered.”
But that may take another 30 years!
I think it’s beyond doubt there’s something missing. If it’s not dark matter, then it’s a problem with GR, which would be an even bigger discovery. So I think she should get the prize this year :) Maybe Kent Ford too? [URL]https://en.wikipedia.org/wiki/Kent_Ford_%28astronomer%29[/URL]
But I’m very impressed with Lars Bergstrom’s diligent search of the literature, uncovering the much earlier work of Lundmark.
I think the Special Relativity Theory would have been discovered without Einstein. Both Poincare and Lorentz were very close. Sooner or later somebody would also have had the idea that the ether is unnecessary and overcomplicating the description of electromagnetic phenomena. Concerning General Relativity I have my doubt whether it would have been discovered as soon as 1915, if Einstein wouldn’t have followed the track for more than 12 years. Planck even suggested to Einstein, he shouldn’t bother about gravity too much, because he thought it would be too complicated a task with little impact for physics. The latter was perhaps true at the time, but for sure it’s not true a bit later when the Hubble expansion (another example for a misnomer, because it should rather be named Lemaitre-Hubble expansion or, as I learned from this great Insights article, Lundmark-Lemaitre-Hubble expansion).
On the other hand, I’m sure that Vera Rubin should get the Nobel for her work on the rotation curves of galaxies. I guess, however, she’ll have to wait until it’s clarified what dark matter is, i.e., the earliest when dark-matter candidate particles are discovered.
The Nobel prize for Einstein is also an interesting story. Ironically, he got it for the only work which is outdated today. The photoelectric effect in the sense Einstein analyzed it in his famous 1905 paper is not due to the quantization of the electromagnetic field but due to the quantization of bound electrons (see my own Insights article on the subject), and photons have very little in common with classical particles, even less than other quanta that have a non-vanishing mass. The wave-particle dualism is obsolete with the discovery of modern quantum theory in 1925.
Of course, the Nobel committee was very right to give a Nobel to Einstein. If a single person deserved the prize at his time it was Einstein for his very broad spectrum of groundbreaking research in theoretical physics. Of course, the most important work was General Relativity, and he should have gotten the prize for this work. However, the theory was much more controversial than today. It’s very interesting that not physics arguments lead to the decision of the Nobel Committee but the criticism from philosophy! Particularly Bergson’s cirticism of the idea of time in relativity lead to doubts about the validity of the theory, and thus the Nobel Committee decided to give Einstein the prize for some other achievement, and they decided for the explanation of the photoeffect. Concerning this interesting story about Einstein’s Nobel Prize, see the book
J. Canales, The Physicist and the Philosopher, Princeton University Press (2015)
“You would have to ask Lars Bergstrƶm who not only stumbled upon the Lundmark papers, but also is the secretary for the Nobel committee in physics. However, I seriously doubt that you will be able to get this information out of him.”
Well, that’s probably why Einstein couldn’t get it for relativity :)
“So should we still consider Rubin deserving of a Nobel, now that she is the second (third?) person to discover dark matter?”
You would have to ask Lars Bergstrƶm who not only stumbled upon the Lundmark papers, but also is the secretary for the Nobel committee in physics. However, I seriously doubt that you will be able to get this information out of him.
So is Rubin still up for a Nobel, now that she is the second (third?) person to discover dark matter?
I had to look up “sensmoral” :)
So should we still consider Rubin deserving of a Nobel, now that she is the second (third?) person to discover dark matter?
What is the status of Zwicky as an early discoverer? Did he do things correctly enough that his claims of dark matter were valid?
“As far as science or knowledge is concerned, it doesn’t matter who find out what first.”
From a hard scientific point of view, no. For how we look at the achievement of historical figures, in particular in connection with science, it plays a very important role. Certainly someone would have discovered relativity even if Einstein had never existed, yet here we are a hundred years later making T-shirts with his face on them.
“Not that it is important.
There is an ‘n’ missing in “Zwicky named this matter āDukle Materieā” ā Zwicky named this matter āDunkle Materieā.”
Fixed.
I shall hoist a brew to Lundmark this very evening!
Indeed, that’s very interesting.
Maybe one reason for not getting the deserved credit is the publication of Lundmark’s findings in a not so well-spread (local?) journal?
An AAS article was released earlier this month [Lost in the Dark: A proto-history of dark matter, [URL]http://adsabs.harvard.edu/abs/2016AAS…22711406][/URL] unfortunately, only the abstract appears to be freely available at present. Another good historical discussion of dark matter can be found here: [URL]http://www.kiss.caltech.edu/workshops/darkmatter2009/presentations/primack.pdf;[/URL] A Brief History of Dark Matter.
Great insight indeed. Unfortunately, history does not always give credits in a fair manner. I don’t know all the details about Lundmark – I’ll definitely dig it deeper, but as far as I know, he deserves the credit. I think, it is in many cases a fairly complex thing, to give credit for a discovery, to the right person. Particular time, person profile and fair knowledge of the importance of a discovery in many respects, are some critical factors.
Not that it is important.
There is an ‘n’ missing in “Zwicky named this matter āDukle Materieā” ā Zwicky named this matter āDunkle Materieā.
In another example of prescient early-20th century Scandinavian physics, Gunnar Nordstrom wrote down the first "spacetime curvature" theory of gravity a few years before Einstein. Unfortunately for him, his theory was wrong, but it was still conceptually important.
As far as science or knowledge is concerned, it doesn't matter who find out what first.
Very interesting Orodruin!