Talk:Einstein's constant
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Laue scalar
[edit]The "Laue" scalar, Tuu = guaTau = T00 - T11 - T22 - T33 - T44. Is this not so ? For if so, then, in non-relativistic scenarios, v << c, |T00| >> |Tii|, and the "Laue" scalar is positive, implying that the Ricci scalar is negative. 24.143.65.75 (talk) 00:25, 29 January 2012 (UTC)
Section "About constants"
[edit]This section is confusing (maybe wrong) and requires high-level references, not the current wording. Why should G/c^2 (and not G/c^4) be constant ? IMHO, several sections should be removed (or better referenced).92.152.255.248 (talk) 23:01, 14 January 2020 (UTC)
Merge?
[edit]This topic does not appear to be notable (I have not able to almost nothing on this constant by this name using Google scholar, though there are often other constants that go by this name, e.g. the cosmological constant). Much of this article's content is also about the Einstein field equation. It seems to me that as such, a separate article is inappropriate, and it should be merged to Einstein field equations. —Quondum 13:10, 23 July 2020 (UTC)
- Given that the text violates the injunction about writing like a textbook, I think a cleanup would be necessary prior to a merge. Moreover, it seems to be an arbitrary choice to insist that the term "Einstein's constant" must refer to a quantity appearing in the field equations. Sometimes it does, but despite the article's assertion, in practice it can refer to the cosmological constant, to the speed of light, or even a quantity in fluid dynamics that shows up in the study of sedimentation rates. The term "gravitational constant" is orders of magnitude more prevalent, and we already have an article for that. I don't think giving a special name to the number that is just the other constant rescaled is a very prevalent practice. XOR'easter (talk) 05:26, 25 July 2020 (UTC)
- Interesting that your first reference gives an in-between variant, 8πG/c3. Looking more closely, I expect to scrap the entire body of the article in the merge: it seems to be essentially peripheral to the topic (namely the constant and where it appears), and is largely an exposition of the EFE, which as you say, is too textbookish. I don't see how including any of that in Einstein field equations will improve that article. I have adjusted Gravitational constant to be more encyclopaedic on this constant (it already had a mention; I just copyedited it), and I propose to adjust Einstein field equations to reflect Einstein's original use of κ and use of the Einstein tensor, simply to call it a constant originally introduced by Einstein and show its relationship to G; this would be the "merge" of the lead into that article. I expect the best will be to simply replace this article with a disambiguation page, which I see it was at some point in the past. —Quondum 22:19, 25 July 2020 (UTC)
- That all sounds reasonable. XOR'easter (talk) 23:50, 25 July 2020 (UTC)
- Done. XOR'easter, would you mind adding a DAB entry for his constant of viscosity, if indeed there is such a (universal) constant? I would not consider it appropriate if such a thing is fluid-specific (i.e. not general constant). —Quondum 01:26, 29 July 2020 (UTC)
- That all sounds reasonable. XOR'easter (talk) 23:50, 25 July 2020 (UTC)
- Interesting that your first reference gives an in-between variant, 8πG/c3. Looking more closely, I expect to scrap the entire body of the article in the merge: it seems to be essentially peripheral to the topic (namely the constant and where it appears), and is largely an exposition of the EFE, which as you say, is too textbookish. I don't see how including any of that in Einstein field equations will improve that article. I have adjusted Gravitational constant to be more encyclopaedic on this constant (it already had a mention; I just copyedited it), and I propose to adjust Einstein field equations to reflect Einstein's original use of κ and use of the Einstein tensor, simply to call it a constant originally introduced by Einstein and show its relationship to G; this would be the "merge" of the lead into that article. I expect the best will be to simply replace this article with a disambiguation page, which I see it was at some point in the past. —Quondum 22:19, 25 July 2020 (UTC)