# Talk:Retarded potential

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--Griffiths--

I wrote these equations in to paste them into a paper I was writing, which is due in a little over 24 hours. I will fix up the page later. I used Griffiths' Introduction to Electrodynamics (1999), and followed his notation for the most part.

Mgummess 02:24, 15 May 2007 (UTC)

## Need a General Explanation of Retarded Potential

It would help, if the person who wrote this item, would return and give a general, plain language explanation of the meaning of this term. I first ran across it in a two-volume work by Alfred O'Rahilly on "Electromagnetic Theory" which was first published in 1938 by Univ. of Cork Press and republished in 1965 by Dover. What I got out of it (very crudely and perhaps wrongly) was that the mathematics of EM fields should take into account the finite speed of light, so e.g. forces exerted by one object on another distant object (EM or gravity I suppose) are not instantaneously exerted between the objects where they are "now" but where they "were" at some time in the past, roughly d/c where d is the distance between them and c is the speed of light. Taylour (talk) 20:05, 18 November 2007 (UTC)

I am not the person, you thought of, but I have read your remarks and took reason from them to improve (I hope so!) the introduction essentially.

- 87.160.60.134 (talk) 08:21, 29 October 2008 (UTC)

Dude, isn't retarded potential an all famous concept that is used throughout physics? I'm surprised (disappointed) at this small section on the topic. I, unfortunately, don't know enough to add anything yet. —Preceding unsigned comment added by 131.211.109.69 (talk) 14:44, 7 May 2009 (UTC)

The use of retarded potentials is better understood in the framework of relativity. I've added a hyperlink to the Liénard–Wiechert potential which is a relativistically invariant retarded potential. That should help increase the understanding of the concept.99.37.226.68 (talk) 04:54, 1 January 2010 (UTC)

## I really don't like this

I would really appreciate if wiki would consider wording this in a more socio-sensitive way. I have a niece who's neuro-atypical and I really think this article is thoroughly offensive for its heavy use of The R word. 64.123.99.139 (talk) 01:54, 4 March 2012 (UTC)

You took the words right out of my mind, I agree that this article is in an absolutely sorry and appalling state... I have rewritten it, although "retarded" in this context is actually used in the literature unfortunately. I tried to reduce the amount its used... 12:16, 26 May 2012 (UTC)
It could be noted that retarded potentials (and presumably advanced potentials as well) occur in the vector potential part of the Coulomb gauge potentials. Xxanthippe (talk) 22:46, 26 May 2012 (UTC).
I thought the retarded potentials occur for any gauge, am I wrong? At the time of rewriting I happened to have Griffiths' book to hand and was typing from it, the Lorenz gauge seems to be the easiest to talk about... 23:02, 26 May 2012 (UTC)
In the Coulomb gauge the scalar potential is formally instantaneous. The vector potential is partially retarded (or advanced as the case may be). Also, explicit expressions should appear for the retarded and advanced times. Xxanthippe (talk) 23:06, 26 May 2012 (UTC).
Sorry about the delay (I'm "retarded"!?), I was distracted and had to do something else. How is the new section? I couldn't find a source for the solution of the coulomb gauge potential for A so had to copy the form in coulomb gauge, if that's ok (that was cited from Jackson)... 23:43, 26 May 2012 (UTC)