Posted on 01/15/2002 7:02:17 AM PST by PatrickHenry
Hi VR. I believe the need for dark matter comes from the anomalous falloff in the rate of rotation as one goes from the center of a galaxy out to the edges, so the mass of the black hole in the center doesn't come into play. The effect of dark matter comes from a mass that is much more spread out than that of a black hole.
What are you urging here, surrender to ignorance? Science stumbles and bumps its way, converging upon an ever-better understanding of the universe.
Somehow, this bothers some of you unduly. I need to explain that. You're not upset that science has to revise the picture, but that it's clearly getting somewhere. On FR, there's lots of cheering for the gaps, rooting for ignorance. In fact, our ignorance is routinely exaggerated to avoid dealing with facts that have been established for well over a century. A strange position!
That's correct. Black holes have been inferred at the centers of several galaxies from star motions near the centers. The hitch is that stars' galactic orbital velocities don't generally seem to drop off with distance from the center as fast as one might expect.
There's a great website on the Milky Way's black hole at Black Hole Slide Show. The slide show includs an actual movie of stars, not an animation, of stars in motion around the black hole. (You can download the movie from Black Hole Movie.)
That's correct. Black holes have been inferred at the centers of several galaxies from star motions near the centers. The hitch is that stars' galactic orbital velocities don't generally seem to drop off with distance from the center as fast as one might expect.
There's a great website on the Milky Way's black hole at Black Hole Slide Show. The slide show includes an actual movie of stars, not an animation, of stars in motion around the black hole. (You can download the movie from Black Hole Movie.)
It seems to me that the humble ones would be the ones still looking for answers -- the scientists.
I have no problem whatsoever with scientific progress, and you won't find a post of mine anywhere where I take a position which even remotely suggests otherwise.
The most beautiful thing we can experience is the mysterious. It is the source of all true art and science.
Albert Einstein, What I Believe
As long as the brain is a mystery,
The universe will also be a mystery
Santiago Ramón Y Cajal
Subjective existence, baby. Why is there something rather than nothing? How did we get here? Those are the only "scientific problems" that count. We are no closer to solving them than was Plato.
Are you a hardcore materialist, moonman? In the past, that has not been my impression of you. Indeed, scientific inquiry is an ennobling and, usually, humbling enterprise. It deserves high praise. But another strain of thought has recently come to the fore, one which assumes knowledge of final truths. Perhaps it is best expressed by Nobel prize winning physicist Steven Weinberg, who wrote that he is all in favor of "a dialogue between science and religion, but not a constructive dialogue. One of the great achievements of science has been, if not to make it impossible for intelligent people to be religious, then at least to make it possible for them not to be religious. We should not retreat from this accomplishment." I interpret Weinberg's use of the term "religion" as synonomous with "respect for mystery."
Hardcore materialists, as I define them, believe that "intelligent" people have solved the problem of existence, and that there are no unknown unknowns. To me, such thinking is foolishness beyond reckoning.
It is constant in a vacuum. I'm not aware of that having changed.
I guess this is related to the mysterious gravitation effects on our deep space probes. I also wonder if this is related to the flavor changing solar neutrinos. It is troubling to me that a particle so inert to interaction with matter that it can pass through light years of lead and yet it "coyly" metamorphoses in ~93 million miles of vacuum.
Actually, that is the result of Fundamentalist Christians punishing scientists who tried to believe in God who were also advancing science because their discoveries and theories were 'detrimental' to the fundamentalist doctrine.
Although I am no scientist, I am considered less of a Christian by the fundamentalists who engage in the crevo debates and by those whom I know IRL because I "believe in" evolution (not being ignorant, etc.)
You are correct, of course. Maintenence of truth requires constant vigilence.
You might want to read this article.
Determining the Rotation Curve of the Milky Way Galaxy
The rotation curve of a system is a plot of the orbital speed versus the distance from the center of the system. For different objects, or systems of objects, different rotation curves result. For example, the rotation curve of a disk is a line with a positive slope, because as you move outward on the disk, the angular velocity remains constant. A planetary system has a different kind of rotation curve. The angular velocity is not constant in this case, and the velocity decreases as the inverse of the square root of distance. The third type of rotation curve, and the one exhibited by spiral galaxies, is a flat rotation curve.
A flat rotation curve implies that the mass increases as distance from the center increases. The rotation curve, when plotted, did not agree with previous estimates, which were made based on the luminous matter in the galaxy. It was therefore concluded that there is much more matter in the galaxy than is luminous.
Since the advent of radio astronomy, the 21-cm emission line of HI has been a vital part of the study of the kinematics of the Milky Way. It was predicted in the early 1940s and was first observed in 1951. This line is produced by a flip in the spin of an electron. Most of the Galaxy is optically thin to the 21-cm line, making it an excellent resource for determining the rotation curve of the Galaxy.
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