I will never pretend to understand the math behind the new paper that is attempting to crash about 50 years of very heavy intellectual work that determined a staggering 85% of matter in our universe does not interact with our senses or the instruments that enhance their powers. Because this stuff is invisible, we call it dark matter. Credit for the confirmation of this known unknown is attributed to Vera Rubin, an American astronomer who for reasons that are just too obvious (she = not he) wasn't granted a Nobel prize for her work in the 1960s on the rotation curves of galaxies.
To understand what her observations determined, your image of a galaxy must be set in motion. Stars and dust and clouds of gas (the nursery of stars) must swirl around its core like the earth does around the sun, and the moon around the earth, and the Lunar Reconnaissance Orbiter around the moon. But Rubin noticed a discrepancy at the galactic scale. The fast speed at which stars on the periphery of, say, Andromeda, moved did not correspond with the gravitational force in that galaxy's star-dense core. What was holding this and other galaxies together if it wasn't gravity? Because no answer was available, this missing stuff became our dark matter of today.
And when dark matter was coupled with dark energy, a truly magnificent (thought-bending) force that was confirmed near the end of the 1990s and that is creating space at an increasing rate, we basically were, at the beginning of the 20th century, on an island of reality that only accounted for 4% of the universe.
But last month, The European Physical Journal published a paper by a Brazilian physicist named Gerson Otto Ludwig. He seemed to have had it up to here with all this growing darkness around physics—or the Standard Model, which is still our most comprehensive description of the stuff of reality—and attempted to bring back some light with a paper called: "Galactic rotation curve and dark matter according to gravitomagnetism."
To get some sense of the math involved in this paper's argument, one can read Scott Locklin's post "Humble tokamak physicist owns generations of cosmological wankers." (I have to thank Steven Shaviro, one of the world's top commentators on the work of the 20th century mathematician and philosopher, Alfred North Whitehead, for bringing Locklin's blog to my attention.)
This is how Locklin throws down:
The author, Gerson Otto Ludwig, is a lifelong plasma physicist from Brazil; a noble profession, even if controlled nuclear fusion is unlikely as a near future energy source. Plasma physics is a fiendishly difficult field; it is both mathematically difficult and unlike the more “woo” grandiose kinds of physics hiding behind formalism, your ideas are generally testable by experiment. Maybe some cosmological wanker pissed him off, and he said “segure minha cerveja.” Maybe he just noticed something from fooling around with magnetohydrodynamic models all day. But if he’s right, he’s basically written the most dramatic single paper own of the physics and astronomy community, like ever.
All of that is interesting, and time will tell if Ludwig has indeed helped humanity recover a stunning 27% of the universe. But there is something also important to consider here. Locklin, a young physicist I gather, did not study general relativity. ("I never studied GR; had the opportunity to do so with the great Ezra Newman and Carlo Rovelli.") For him, and many like him, it was old hat. And there's no denying that it's old—over 100 years old. But Ludwig's calculations are built on the foundation of Albert Einstein's history-making GR.
...[U]nless I’m missing something big here, it’s all straightforward stuff; a workman like piece of physics scholarship, and it seems to give the right answer (I haven’t checked). If he’s right, it’s going to make lots of people real mad, then sad for their wasted lives.
How does a physicist not know GR? It's like an English major who has never read Hamlet. It's just so bizarre, and it reminds one of why scientists tend to be so culturally desiccated. There are, for example, biologists who have never read Charles Darwin's On the Origin of Species. A fact that was made clear to me when I read in David Quammen's rather unsatisfying The Tangled Tree: A Radical New History of Life that the microbiologist who discovered a whole new branch of life (Archaea) back in 1977, Carl Woese, did not read the founding document of his profession, Origin, until near the end of his life. On learning this, I wondered how many biologists at UW, a leading science institution had ever opened that book, which is also a masterpiece of English writing? (Indeed, when I talk with evolutionary biologists, I fear bringing up Origins out of fear of sounding snobby.)
But physicists treat GR in much the same way. Read The Perfect Theory: A Century of Geniuses and the Battle Over General Relativity by the Portuguese-born physicist Pedro G. Ferreira. It is an excellent biography of GR (its ancestors, its birth, its golden age). But what we find in every chapter is an author, who is still young (late 40s), doing his best not just to explain the theory and its history, but also to make a case for its relevance. This is the theory of general relativity. How in the world did physics get in such a dismal predicament? How can you be so uncultured? GR, one of the greatest works of human thinking, dismissed like a burnt piece of bacon. No wonder the Brazilian is saying such amazing things about dark matter.