Equation 101 · Part 1 · The Clock That Comes Back Wrong by Exactly Its Mass

Symbol H_rm int

H_{\rm int}

H_{\rm int}

What this part means

$H_r$ m int is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

$H_r$ m int is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Full expressionSymbol H_rm intArticle meaning

The passage around this formula

…ordinary mass–energy equivalence — no redefinition of either the relativistic or the everyday meaning of mass, simply the standard bookkeeping in which a system’s total rest energy M $c^2$ includes whatever internal energy $H_{\rm int}$ it holds: M= $M_0$ + $H_{\rm int}$ / $c^2$ . If the same object is sent along two paths that differ in proper time by $\Delta$ $\tau$ , and its internal state differs between the two paths — ground on one, excited on the other — then the two branches’ free-particle phases differ by

Read this part in the article →

Learn the underlying idea

A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

Open the illustrated subscripts: which member of a family? guide →

See this notation across published equations →

Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.