Editing Invariant mass (section)

== Rest energy ==
'''Rest energy''' (also called '''rest mass energy''') is the energy associated with a particle's invariant mass.<ref name="Hyperphysics Rest Energy">{{cite web |last1=Nave |first1=C.R. |title=Relativistic Energy |url=http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/releng.html#c2 |website=HyperPhysics |publisher=Georgia State University |access-date=28 August 2023}}</ref><ref name="Douglas University">{{Cite web|url=https://pressbooks.bccampus.ca/introductorygeneralphysics2phys1207opticsfirst/chapter/28-6-relativistic-energy/access-date=2023-09-07|title=13.6 Relativistic Energy or E = m c^2}}</ref>

The rest energy <math>E_0</math> of a [[Elementary particle|particle]] is defined as: <math display="block">E_0 = m_0 c^2,</math> where <math>c</math> is the [[speed of light|speed of light in vacuum]].<ref name="Hyperphysics Rest Energy" /><ref name="Douglas University" /><ref>{{cite report |author=Phillip L. Reu |date=March 2007 |title=Development of the Doppler Electron Velocimeter—Theory |publisher=Sandia National Laboratories |id=SAND2006-6063 |url=http://www.prod.sandia.gov/cgi-bin/techlib/access-control.pl/2006/066063.pdf |url-status=dead |archive-url=https://wayback.archive-it.org/all/20150623204045/http://www.prod.sandia.gov/cgi-bin/techlib/access-control.pl/2006/066063.pdf|archive-date=2015-06-23}}</ref> In general, only differences in [[energy]] have physical significance.<ref>{{cite book| last=Modell|first=Michael|last2=Reid|first2=Robert C.| date=1974| title=Thermodynamics and Its Applications| publisher=[[Prentice-Hall]]| location=Englewood Cliffs, NJ| isbn=0-13-914861-2| url-access=registration| url=https://archive.org/details/thermodynamicsit00mode}}</ref>

The concept of rest energy follows from the [[special theory of relativity]] that leads to Einstein's famous conclusion about equivalence of energy and mass. See ''{{section link|Special relativity#Relativistic dynamics and invariance}}''.