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By priestess (Tue Feb 21, 2006 at 02:45:59 AM EST) gravity, swearing, pie, lunch, physics (all tags)
Ooops. I seem to have been drinking in front of the computer again. (Warning: Content may offend). Oh well.

An physisists in the house?



I was reading this article on the speed of gravity which surprised me by more or less convincing me that gravity doesn't travel at the speed of light afterall. This is news to me, non-locality seems to crop up all over the place in physics these days. Curiousier and curiouser.

Went for a pub lunch this weekend and had lovely pie. Mmmm. Pie is nice. Not enough gravey with the mash though.

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A Diary Entry | 12 comments (12 topical, 0 hidden) | Trackback
That article's made my day interesting. by ambrosen (4.00 / 2) #1 Tue Feb 21, 2006 at 02:49:41 AM EST
Thank you. It's something that had always bothered me.

Here's a question by DesiredUsername (2.00 / 0) #2 Tue Feb 21, 2006 at 02:57:23 AM EST
Does the question of dark matter depend on gravity propagation speed?

Personally, I've never been convinced by the idea of gravitons--they interact with matter but can't be blocked?

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Good question by priestess (2.00 / 0) #3 Tue Feb 21, 2006 at 02:58:59 AM EST
I don't know the answer I'm afraid though.

Sometimes I think maybe gravity was just a wild flight of fancy from Newton and it doesn't really exist. We're all just stuck to the earth though a massive placebo effect.

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Surely, a sufficiently massive placebo by Evil Cloaked User (4.00 / 1) #4 Tue Feb 21, 2006 at 04:44:34 AM EST
Would cause a noticeable gravitational force.

[ Parent ]
Goon show quote by Herring (4.00 / 1) #12 Tue Feb 21, 2006 at 09:45:05 AM EST
Seagon attempting to explain gravity to Eccles
S: Jump in the air ... see, you came back down to earth. Why was that?
E: I live here

christ, we're all old now - StackyMcRacky
[ Parent ]
It would if the propagation velocity were variable by joh3n (2.00 / 0) #7 Tue Feb 21, 2006 at 05:15:03 AM EST
which it is not.

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nope by joh3n (2.00 / 0) #5 Tue Feb 21, 2006 at 05:08:48 AM EST
Speed of light for gravity.  The article is bunk.

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Yeah, see, I was hoping someone would say that by priestess (4.00 / 1) #8 Tue Feb 21, 2006 at 05:18:08 AM EST
Only I was hoping for a bit more detail really.

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Where shall I begin by joh3n (2.00 / 0) #9 Tue Feb 21, 2006 at 05:32:39 AM EST
The author misses the boat completely on just about every issue.  Claiming, for example, that a lack of detection of gravity waves with earth based experiments means that they dont exist is bunk because, as they have been currently designed, the experiments should be missing the run of the mill gravity wave event.  What's better is that the author offers the evidence for them (PGwhateveritis, of which there are a few other examples), but just kinda forgets that evidence.

Second, the author missed the boat on advanced and retarded waves.  Half of the time, this is simply a mathematical trick we use to make the solution easier to get at.

Third, the author drops the ball on the newtonian limit of GR.  Conservation of angular momentum is not required to solve it at all.

Fourth, I think the author doesnt understand the spacetime description of GR at all.  With that description (hold on to your seat) there is no gravitational force.  None.  By curving spacetime as a result of mass-energy, you remove the force, since the trajectory of the particle is changed along with the spacetime it inhabits.

I could go on, but that would mean opening the article again, and I'm too dang lazy.

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I wish I had the time too by priestess (2.00 / 0) #10 Tue Feb 21, 2006 at 05:40:25 AM EST
To bring up the points I found interesting and ask for rebuttals from somewhere I mean. Damn this having to work for a living.

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Agreed by joh3n (4.00 / 1) #11 Tue Feb 21, 2006 at 05:43:48 AM EST
If you have the time later, bring them up later, and I'll look at them and respond.....later.

Either that, or we could both quit our jobs and PARTY1

1partying may include GR wankery

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[ Parent ]
But I neglected to mention by joh3n (4.00 / 1) #6 Tue Feb 21, 2006 at 05:10:50 AM EST
PIE PIE PIE PIE PIE PIE

Pie is very very good.

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A Diary Entry | 12 comments (12 topical, 0 hidden) | Trackback