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Unformatted text preview: After hearing so much about "flat rotation curves", it is important to point out that many spirals don't show flat forms - they show more or less linearly rising rotation patterns over much of the disk, especially for the numerically dominant low-luminosity late-type spirals. I'll illustrate this with part of a random page from the immense data paper by Mathewson, Ford, & Buchhorn (1992 ApJS 81, 413, courtesy of the AAS, as usual): One might also ask whether the disparity can be explained if it's not the mass that's missing, but our understanding of gravity. After all, we have no experimental verification of how gravity works beyond 50 AU (well it seems to work fine for globular cluster internal motions, so we could call that a confirmation at scales of tens of parsecs) or at extremely small accelerations. Milgrom has asked this repeatedly, proposing a modified Newtonian dynamics (MOND) in which there is a minimum possible acceleration in response to a gravitational potential. However, which there is a minimum possible acceleration in response to a gravitational potential....
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This note was uploaded on 11/10/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.
- Fall '10