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If we are talking about the rest mass of the electron, I believe the units should be reported as [m_e]=MeV/c^2 —Preceding unsigned comment added by 99.174.160.173 ( talk) 18:22, 13 February 2011 (UTC)
The value in this article is 5.4857990943(23)×10−4 u; in other words the true value is expected to fall within the range of 5.4857990920×10−4 to 5.4857990966×10−4.
But the new measurement published by the Max Planck Institute for Nuclear Physics/Sven Sturm et. al. -- 5.48579909067×10−4 u -- is smaller than that lower limit.
Anyone have any thoughts on this? 75.163.218.148 ( talk) 15:33, 20 February 2014 (UTC)
"Rest mass", as a concept, is emphasized in older texts. Modern texts view the mass of a particle, or s system of particles, as a Lorentz invariant quantity. The advantages are clear: Relativity is in many ways a theory of invariants, with inertial mass being the poster child for a concepts that is frame invariant. The older grouping of "gamma" with "m" and renaming this combination the "relativistic" (and non-constant) mass is not a necessity. It even leads to unnecessary confusions like "longitudinal mass" and "transverse mass". This article is the place to point that out. Qwerty123uiop ( talk) 14:32, 13 December 2018 (UTC)
In this expression me is the "rest mass", or more simply just the "mass" of the electron. This quantity me is frame invariant and velocity independent. However, some texts group the Lorentz factor with the mass factor to define a new quantity called the relativistic mass, mrelativistic = γme. This quantity is evidently velocity dependent, and from it arises the notion that "mass increases with speed". This construction is optional, however, and adds little insight into the dynamics of special relativity.
This is a ridiculously untethered observation until you point out which of these masses get substituted into F = ma.
Does that equation only work in a rest frame? So you always apply it in a rest frame, and deal with everything else in a frame transform? That would be pretty weird: a law of motion that's only precisely accurate for objects that don't move.
And don't go thinking the average reader is less screwed up about this than I am. Make the reasoning here far more explicit. — MaxEnt 16:47, 23 April 2019 (UTC)
" The relative uncertainty, 5×10−8 in the 2006 CODATA recommended value,[3] is due entirely to the uncertainty in the value of the Planck constant." ummm... I thought they fixed the definition of the Kilogram by fixing the value of the Planck constant. Doesn't that change this article a bit? 71.93.61.178 ( talk) 01:10, 25 June 2019 (UTC)
The result of the move request was: moved per request. Favonian ( talk) 15:50, 30 January 2022 (UTC)
Electron rest mass → Electron mass – no need to specify Heanor ( talk) 15:01, 23 January 2022 (UTC)