Gregg's friend Carl is a physicist his old company hired to come up with new ethanol formulations. He's a full bore stream of consciousness emailer like somebody else I know before they gave up on email :)
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Gregg,I also thought you'd be amused to find out that despite my not believing in special relativity, my software simulation of Einstein's gravity will be used to help teach grad students at MIT (see below).Also, there is a full on food fight going on in the physics community with the publication of this paper:http://arxiv.org/abs/0711.0770and I think I can connect to it with my preon theory.Max Tegmark <tegmark@MIT.EDU> wrote: CC: Max Tegmark <tegmark@mit.edu>, Enectali Figueroa <enectali@mit.edu>, Edmund Bertschinger <edbert@mit.edu>, "Scott A. Hughes" <sahughes@mit.edu>, Edwin Taylor <eftaylor@mit.edu>, Andrew J S Hamilton <ajsh@origins.colorado.edu> From: Max Tegmark <tegmark@MIT.EDU> To: Carl Brannen <brannenworks@yahoo.com> Subject: Re: River model of black holes and Painleve orbit simulation. Date: Sun, 4 Nov 2007 12:55:00 -0500 Hi Carl, Please accept my sheepish apologies for not getting back to you sooner - your message unfortunately slipped through a crack in the spacetime continuum, and I only read it now. The wikipedia said that you taught GR with the "river model" of black holes. I did indeed, in course 8.033. Because of this, I suspect you will enjoy showing your students my Java simulation, Many thanks for pointing me to this! It looks very useful indeed, and I'm sure I'll use it next time I teach GR. I'm not teaching it again anytime soon, but I"m forwarding your email to a few others who I think will like it: Enectali Figueroa, who's teaching it this semester, my GR colleagues Ed Bertschinger, Scott Hughes & Ed Taylor, and to my old friend Andrew Hamilton, one of the river model pioneers. Thanks again, Max ;-) -------------------------------------- Prof. Max Tegmark Dept. of Physics, MIT 70 Vassar Street Rm. 37-626B Cambridge, MA 02139 Carl Brannen wrote: Dear Dr. Tegmark, The wikipedia said that you taught GR with the "river model" of black holes. Because of this, I suspect you will enjoy showing your students my Java simulation, which does both Painleve and Schwarzschild coordinates. It's set up to automatically step through a series of demonstrations of various attributes of gravity. The student can halt the demonstrations and edit the initial conditions: http://www.gaugegravity.com/testapplet/SweetGravity.html Right now I've got 8 or 9 demonstrations, but they're easy to insert and I keep adding more. The comparison between the behavior of Painleve and Schwarzschild coordinates is, I think, very convincing. I can't see why people would still want to use Schwarzschild after seeing Painleve in action. The simulation uses equations of motion defined by varying the integral of ds rather than by going through the Christoffel symbols. This gives just three differential equations instead of four, and it turns out that the Painleve metric is fairly simple when written this way. That is, it's a sum of radial and angular acceleration divided by powers of the radial distance. The Schwarzschild equations of motion are a sum of powers of the radial distance r, and the distance to the event horizon, r-2. The calculation for Schwarzschild equations of motion is messy, and putting it into reduced form is worse. I used MAXIMA as I tend to lose minus signs and the like. Since the simulation is written as equations of motion, it works equally well with massive and massless particles (and tachyons). Carl Brannen