Talk:General relativity/Archive 6

message: My Google skills fail me. Does anyone have a link to the 1915 paper in English (e.g., a PDF)? I just heard an interview on episode 13 of the Scientific American podcast in which Frank Wilczek talks of reading the paper and liking Einstein's writing style (around minute 6). —Ben FrantzDale 14:53, 8 May 2006 (UTC)
thread_title:  Paper source? 

message: The section on quantum mechanics and its interface with general relativity has a glaring omission: quantum field theory in curved spacetime.  We need a paragraph with a link to a main article.  Now who's going to write it? :-) -lethe talk [ +] 02:08, 24 May 2006 (UTC)
thread_title:  quantum mechanics is more than just quantum gravity 

message: I've finished making placeholder versions of figures that more accurately show how spacetime curvature works. If these are deemed useful, they can either be put in as-is or replaced with prettier versions (my drawing and animation tools consist of "xfig" and "convert", respectively). Omit "temp" for the filenames when creating the nicer versions. Sample use and captions are below. Comments are welcome. The main problem I see is that putting these in the article as-is would take up large amounts of space. --Christopher Thomas 01:28, 3 July 2006 (UTC)
thread_title: Placeholder replacement figures

message: I tried to create a WikiProject called WikiProject GTR, but this failed.
Due to the very frequent vandalism of this article, I made few if any substantial edits to it, and have mostly not even tried to monitor it, but from time to time I did point out specific problems in this talk page.  However, I am leaving the WP and am now abandoning this article to its fate.
Just wanted to provide notice that I am only responsible (in part) for the last version I edited; see User:Hillman/Archive.  I emphatically do not vouch for anything you might see in more recent versions.  While as of June 2006 there are still some Wikipedians knowledgeable about gtr, given what I view as the failure of WP as a source reliable information (see recent comments by our founder, Jimbo Wales), and given the lamentable past history of this article, which concerns a topic which attracts many cranks, I have reason to believe that at least some future versions of this article are likely to contain slanted information, misinformation, or disinformation.  Beware also of external links to other websites, some of which may be cranky.  See Relativity on the World Wide Web for a website which is very out of date, but at least provides mostly accurate information.  (This is now displayed by someone else, but the original version was created by myself.)
Good luck to all students in your search for information, regardless!---CH 23:47, 30 June 2006 (UTC)
thread_title: Students beware

message: Hi, does anyone have a citation for Einstein's dismissal of Einstein's gauge formulation of GR?  I've heard this before, and I know it's part of the folklore of the subject, but I'm not certain if I have ever seen it in print.  Thanks for indulging me, Silly rabbit 13:06, 1 July 2006 (UTC)
thread_title:  Citation for the dismissal of Weyl's gauge formulation 

message: I saw an episode of Star Trek: TNG a few days ago, in which an alien woman blew up her spaceship to open a rift in space-time to demonstrate how warp drive is literally tearing the universe apart.  The Enterprise had to enter the fringes of the rift in order to rescue another Federation ship, but entering the rift while using warp drive would simply exacerbate the problem.  They planned to build up momentum at warp 9, then deactivate the warp core and "coast" into the rift.  However, they only had a short amount of time to reach the ship before the gravitational forces pulled it out of their range.  The other ship (the one that needed to be rescued) activated its warp core inside the rift and caused it to expand.  The ending of the episode aside (in which the Enterprise "surfs" out of the rift), isn't this episode somehow violating relativity?  When using warp drive, the ship is actually encased in a space-time "bubble" of sorts while the ship pulls on the space around it to move at high speeds; thus, the ship is not actually moving in the strictest sense.  However, higher warp speeds (such as the Enterprise-D's maximum of 9.3 or something) are extremely fast, and without the warp field around the ship relativity would apply again.  So to my view, Star Trek violated relativity: once the Enterprise deactivated her warp core, relativity would have applied again and it's highly unlikely that the Enterprise would have reached the second ship in time.  Am I getting something horribly wrong here, or did the episode's creators kind of mess up?  (At any rate, could someone tell me which episode that is, because it was really cool!)  --71.219.52.183 13:29, 9 July 2006 (UTC)
replies: text: The Enterprise D has a maximum speed of warp 9.9, and a maximum _sustainable_ speed of somewhere between 9.2 and 9.6 (don't recall offhand). The episode in question was Force of Nature (TNG episode). Long story short, trying to apply real-world physics to Star Trek episodes only results in a headache (the writers weren't scientists). --Christopher Thomas 01:55, 12 July 2006 (UTC)
thread_title:  Star Trek 

message: The first two points in the set of fundamental principles seem to be the same:
:General relativity is based on a set of fundamental principles which guided its development.  These are:
:* The general principle of relativity: The laws of physics must be the same for all observers (accelerated or not).
:* The principle of general covariance: The laws of physics must take the same form in all coordinate systems.
a suspicion that is confirmed by general principle of relativity and principle of general covariance both taking you to the same page, general covariance.  I suggest the first bullet point be eliminated or merged with the second.  --Michael C. Price talk 23:09, 11 July 2006 (UTC)
replies: text: Hello MichaelC. I understand why you may think that the 2 principles are the same, but technically, they are not. The first one refers to the laws of physics, whereas the second one refers to how we write the equations that we believe describe physical phenomena. Clearly, these are different. The redirect must be fixed. I never quite got round to doing it, but will do so sometime soon. Thanks. MP   (talk) 20:40, 12 July 2006 (UTC)
replies: text: OK, I see the distinction, although I'm not sure if they need seperate points: I'll suspend judgement until general principle of relativity is updated.  :-)  BTW I updated another link that got accidentally(?) rolled back with your revert.  --Michael C. Price talk 21:07, 12 July 2006 (UTC)
replies: text:  I'll try and create the general principle of relativity page sometime soon. Sorry about the accidental revert which killed the link - I didn't realise that there was a page called Local Lorentz covariance - we need such a page. Thanks for creating it. MP   (talk) 21:14, 12 July 2006 (UTC)

text: Finally got round to creating general principle of relativity - now it just needs some proper content. MP   (talk) 18:10, 28 August 2006 (UTC)
thread_title: Fundamental principles

message: What causes mass to curve space-time? Also, what are the geodisics that entities follow through space-time called?
--scienceman 16:49, 13 July 2006 (UTC)
replies: text: In response to your questions:
* What causes mass to curve space-time ? - General relativity has no answer to this; it's just an assumption of the theory. This is one of the unsolved problems of physics - if we could answer it, then it would provide us with much valuable information for a theory of quantum gravity.
* What are the geodesics that entities follow through space-time called? - I'm not sure I understand this question (does the question make any sense?). The paths that free particles and light beams follow in spacetime are called geodesics. Worldlines are trajectories (paths) of particles and light beams whether they are or are not being acted upon by external forces. So, all geodesics are worldlines, but not all worldlines are geodesics. MP   (talk) 19:15, 13 July 2006 (UTC)
thread_title:  Cause of curvature