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from the changing-our-understanding-of-the-universe dept.
Arthur T Knackerbracket has found the following story:
[...] Renowned astrophysicist and National Medal of Science awardee Vera Rubin passed away in Princeton N.J., the evening of December 25, 2016, at the age of 88. Rubin confirmed the existence of dark matter—the invisible material that makes up more than 90% of the mass of the universe. She was a retired staff astronomer at the Carnegie Institution's Department of Terrestrial Magnetism in Washington, D.C.
"Vera Rubin was a national treasure as an accomplished astronomer and a wonderful role model for young scientists," remarked Carnegie president Matthew Scott. "We are very saddened by this loss."
In the 1960s, Rubin's interest in how stars orbit their galactic centers led her and colleague Kent Ford to study the Andromeda galaxy, M31, a nearby spiral. The two scientists wanted to determine the distribution of mass in M31 by looking at the orbital speeds of stars and gas at varying distances from the galactic center. They expected the speeds to conform to Newtonian gravitational theory, whereby an object farther from its central mass orbits slower than those closer in. To their surprise, the scientists found that stars far from the center traveled as fast as those near the center.
After observing dozens more galaxies by the 1970s, Rubin and colleagues found that something other than the visible mass was responsible for the stars' motions. Each spiral galaxy is embedded in a "halo" of dark matter—material that does not emit light and extends beyond the optical galaxy. They found it contains 5 to 10 times as much mass as the luminous galaxy. As a result of Rubin's groundbreaking work, it has become apparent that more than 90% of the universe is composed of this invisible material. The first inkling that dark matter existed came in 1933 when Swiss astrophysicist Fritz Zwicky of Caltech proposed it. But it was not until Rubin's work that dark matter was confirmed.
Besides her remarkable scientific contributions, as noted by colleague Neta Bahcall of Princeton University: "Vera was an amazing scientist and an amazing human being. A pioneering astronomer, the 'mother' of flat rotation curves and dark-matter, a champion of women in science, a mentor and role model to generations of astronomers."
-- submitted from IRC
(Score: 2) by c0lo on Friday December 30 2016, @04:16AM
Just assume there's a "screening factor" to the gravity law, pretty much as the electric force damps in the presence of dielectrics. Compute then the "gravitational permittivity" and you have a testable theory potentially testable in the lab (assuming the instruments are sensitive enough).
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by maxwell demon on Friday December 30 2016, @11:45AM
Dark matter is also a testable theory. Guess what people are searching for in accelerators? (Besides supersymmetric particles, of course).
Of course there is a chance that it ultimately turns out that it doesn't exist, but that's exactly what science is about. Neptun, the planet conjectured to explain the deviation s of Neptune's movement from the predictions, turned out to be real. Vulcan, the planet conjectured to explain the deviation of Mercury's movement from the predictions, turned out not to be real; rather the deviations were explained by a new theory of gravitation, Einstein's General Theory of Relativity.
Also note that Einstein did not find that theory by looking at the movement of Mercury, and would never have found it that way.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by maxwell demon on Friday December 30 2016, @12:06PM
This of course should have read:
The Tao of math: The numbers you can count are not the real numbers.