Glossaire beginning with D

Deuterium

Isotopic nucleus of hydrogen nucleus consisting of a proton and a neutron. Symbol : 2H or D.

Doppler-Fizeau (effect)
Variation Δλ of the wavelength λ received from a source moving with respect to the observer with velocity v, the emitted wavelength being λ0. One has Δλ/λ0= v/c, where c is the velocity of light.