[math-fun] Donald Saari on Dark Matter
Clark & Meeker sent me Saari's paper. One thing that is ludicrous in his paper is stability. Saari says he will consider a solution of the equations of motion to be "stable" if it keeps the moment of inertia time-invariant. That is like saying that a pencil balanced on its point is "stable" because its potential energy, according to the exact solution, stays constant. Utter hogwash, and Saari sacrifices most of any teeny tiny hope he might have to producing physically relevant results and being taken seriously, with that decision. What is the actual stability status of Saari's "spider web" configurations? You will not find out by reading his paper.
The Bullet Cluster is a pair of galactic clusters that have collided. The gas clouds have interacted, and turned into an X-ray source from shock wave heating. The majority of the mass, as imaged by gravitational lensing, has passed on through without disturbance. This object is considered to be evidence for the actual existence of dark matter. -- Gene
http://www.theonion.com/article/astronomers-just-going-go-ahead-and-say-dark... <http://www.theonion.com/article/astronomers-just-going-go-ahead-and-say-dark-matte-50857>
On Jul 17, 2015, at 8:14 PM, Eugene Salamin via math-fun <math-fun@mailman.xmission.com> wrote:
The Bullet Cluster is a pair of galactic clusters that have collided. The gas clouds have interacted, and turned into an X-ray source from shock wave heating. The majority of the mass, as imaged by gravitational lensing, has passed on through without disturbance. This object is considered to be evidence for the actual existence of dark matter. -- Gene _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
Apparently, the question dates to the 1780s:, 50 years before Maxwell was born: https://en.wikipedia.org/wiki/Oh_Dear!_What_Can_the_Matter_Be%3F At 05:10 PM 7/18/2015, Tom Knight wrote:
http://www.theonion.com/article/astronomers-just-going-go-ahead-and-say-dark... <http://www.theonion.com/article/astronomers-just-going-go-ahead-and-say-dark-matte-50857>
On Jul 17, 2015, at 8:14 PM, Eugene Salamin via math-fun <math-fun@mailman.xmission.com> wrote:
The Bullet Cluster is a pair of galactic clusters that have collided. The gas clouds have interacted, and turned into an X-ray source from shock wave heating. The majority of the mass, as imaged by gravitational lensing, has passed on through without disturbance. This object is considered to be evidence for the actual existence of dark matter. -- Gene
participants (4)
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Eugene Salamin -
Henry Baker -
Tom Knight -
Warren D Smith