← All parts of this equation

Equation 106 · Part 1 · The Clock That Comes Back Wrong by Exactly Its Mass

Symbol d

dτ/dt≈1+gz/c2d\tau/dt\approx1+gz/c^2
dd

What this part means

d 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

d is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

To make this concrete without simulation, take the weak-field proper-time rate dτ\tau/dt≈\approx1+gz/c2c^2 for a static height z in Earth’s field, so that holding two branches at a height difference Δ\Delta z for coordinate time T gives Δ\Deltaτ\tau≈\approx g\,Δ\Delta z\,T/c2c^2 . For Δ\Delta z=1\,m\mathrm m and T=1\,s\mathrm s , Δ\Deltaτ\tau≈\approx1.090×\times10^{-16}\,s\mathrm s . Pair this with a single-photon optical clock transition near 698\,nm\mathrm{nm} , comparable to the transition used in strontium-lattice-clock proposals for this kind of experiment [ 11 , 13 ] , giving Δ\Deltaν\nu≈\approx4.295×\times10^{14}\,Hz\mathrm{Hz} and Δ\Delta E=hΔ\Deltaν\nu≈\approx2.846×\times10^{-19}\,J\mathrm J , a mass excess Δ\Delta…

Read this part in the article →

Learn the underlying idea

A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

Open the illustrated variables: a letter stands for a value 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.