A substance, such as mud or dust, that soils someone or something (OxfordDictionaries.com)
Metathesis of M.E. drit, drytt "mud, dirt, dung," from O.N. drit, cognate with O.E. dritan.
Cerk "dirt, filth."
→ dirt + suffix -y.
Fr.: glace sale
Interstellar ice grains with graphite, silicates, or other chemical compounds adsorbed on their surfaces.
dirty iceball model
model-e golule-ye yax
Fr.: modèle de la boule de glace sale
A model for a → cometary nucleus proposed by Fred Whipple (1950-51), according to which the nucleus is a solid body (a few kilometers across) made up of various → ices (→ frozen water, → methane, → ammonia, → carbon dioxide, and → hydrogen cyanide) in which → dust is embedded. Dust particles are liberated when the ices vaporize as the → comet approaches the → Sun, and they get blown away by → solar radiation pressure, often forming impressive, gently curved → dust tails.