Arcadian Functor

occasional meanderings in physics' brave new world

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Marni D. Sheppeard

Tuesday, May 01, 2007

GR Revisited

Sly old Carl Brannen has been busy discussing Schwarzschild black holes in flat space at PF. It seems that particle physics just wasn't interesting enough for him.

Regulars at PF often use cool signatures on their posts. For example, turbo-1 quotes Einstein (1924):

"The ether of general relativity therefore differs from that of classical mechanics or the special theory of relativity respectively, in so far as it is not 'absolute', but is determined in its locally variable properties by ponderable matter."

11 Comments:

Blogger kneemo said...

Sly old Carl Brannen has been busy discussing Schwarzschild black holes in flat space at PF. It seems that particle physics just wasn't interesting enough for him.

This is great news. Perhaps Carl will next cook up some cool java cosmology simulation programs.

May 01, 2007 3:07 PM  
Blogger Kea said...

Heh, cool link! Thanks.

May 01, 2007 3:47 PM  
Blogger Doug said...

Hi Kneemo and Kea
Although I have previously seen this Andrei Linde 'mulitverse' as a still representation, this is the first time that I have observed it as a dynamic simulation.

Other images and 'movies' may be accessed through the Linde web page.

May 02, 2007 12:49 AM  
Blogger kneemo said...

Yes, Linde has some beautiful images of stochastic evolution. To model such processes one plots solutions of stochastic differential equations, such as the Langevin and Fokker-Planck equations. One can study numerical solutions in one, two and three spatial dimensions, where peaks represent new "big bangs" and valleys represent universes like our own.

Simulations are usually coded in C, but maybe Carl can produce something nice in Java.

May 02, 2007 4:09 AM  
Blogger CarlBrannen said...

Okay, I typed up a long note on why I'm wasting my time putting Painleve black hole coordinates into Cartesian form. I'm too tired to proof read it.

May 02, 2007 9:07 AM  
Blogger kneemo said...

Thanks for the summary Carl. Have you done any work on the Reissner-Nordström case? For the more modern treatment, check out Pioline's lectures (e.g., pgs. 4-10 & 23-30).

May 02, 2007 10:44 AM  
Blogger Kea said...

Wonderful essay, Carl. What a pity you just missed the essay competition deadline ... or did you send in an entry?

May 02, 2007 11:34 AM  
Anonymous Gebar said...

Hi,

About the three times and the "three speeds of light" mentioned in the previous Sparling posts, you might want to take into consideration the fact that the proper time of photons seems to be zero, which might mean that they are not affected by one of the time dimentions, they do not move in it (see here for details).

This is based on the premise that the phenomena of Special Relativity are in fact caused by the curved expanding universe, and the Minkowski spacetime is created by the projection of the curved universe on a linear coordinate system. See here for an explanation that shows how this works through a Java simulation.

Kea, if you decide to have a look at the above, please take a look also at this. As I mention in the intro, the article needs the attention of an expert, and I had mainly you in mind when I wrote this. Most probably it is not anything important, but I would like to know if "it's wrong, trivial or already done", and you, along with many of your blog visitors, will be able to answer this question. (You can leave your comments in the discussion page of the article, or alternatively in my blog --if you don't want to register in order to edit the article itself, that is.)

May 02, 2007 11:38 AM  
Blogger Kea said...

Hi gebar, and thanks for your visit. I hope that one of our readers will give some time to all your effort, but I'm afraid I can't make this a priority myself at present (WAY too much to do), and I'm probably not the best person to ask anyway. Cheers.

May 02, 2007 12:28 PM  
Anonymous Gebar said...

Hi Kea,

I understand.

However, I have something for Tommaso, and all other posters who have problems posting comments in Blogger. The problem is not that you make some mistake in the security letters. It is that if you use the option "Other" (when you do not have a Blogger account), you should not put "http://" in front of your site's url. Just "www". And always, of course, before hitting preview or publish, select+copy what you have written so you don't have to type it again if Blogger has a hiccup. I have checked this repeatedly and it works.

So, Tommaso, we can now enjoy your comments without you fraying your nerves. (It seems that when you have this problem in repeated attempts to post a comment, at some point you forget to put the "http://" in front of your site's url, and then the post goes through.)

And btw, greetings from a neighbor (I am Greek). If your time allows, I would like to hear any comments you may have about what I propose.

May 02, 2007 11:47 PM  
Anonymous Gebar said...

And it seems that with all this explaining about urls, I forgot to put mine in the previous post. lol.

OK, this is embarassing, but it seems that my well checked out solution does not work. I had this problem when trying to post the first comment in the thread, and it went through only when I removed the http:// in front of the url. In the second comment, the post went through but without the link of my site in the poster name. And in the third post, this one, the comment got through again but without the link in my name. When I added the http:// it went through again with the link, no problem. So ignore my suggestion, it seems it needed more extensive testing. Probably I was wrong, or else Blogger is acting up.

May 03, 2007 12:23 AM  

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