- density
- Measured in grams per cubic centimeter (or kilograms per liter); the
density of water is 1.0, iron is 7.9, and lead is 11.3.
diaplectic glass
- A natural glass formed by shock pressure from any of several
minerals without melting; it is found only in association with
meteorite impact craters.
dielectric constant
- The ratio of electric flux density to electric field.
disk
- The visible surface of the Sun (or any heavenly body) projected
against the sky.
Doppler effect
- The apparent change in wavelength of sound or light caused by
the motion of the source, observer or both.
dorsum
- A ridge.
