Irradiance - A radiometric term for the powerof electromagnetic radiation at a surface, per unit area. "Irradiance" isused when the electromagnetic radiation is incident on the surface.Irradiance data
may be reported in any units (i.e. counts/s) due to, forexample, being at a particular wavelength, or to being anot-fully-calibrated relative measurement.
In situ measurements of the relative flux or density of
electrically charged particles in the space environment.
May give simple fluxes, but full distribution functions are
sometimes measured.
A snow particle, sometimes covered with rime, without visible crystalline facets; sometimes used as a last category for snow identification. (Sometimes called amorphous snow.)
A galaxy with no spiral structure and no symmetric shape. Irregular galaxies are usually filamentary or very clumpy in shape and tend to smaller than others. Two types of irregular galaxies are define
d, Irr I galaxy and Irr II galaxy.