The opposition effect is a nonlinear surge of brightness towards the backward scattering geometry.
Note that the opposition effect is a distinctive feature for asteroids of various types (e.g., Belskaya and Shevchenko, 2000).
Thus, comets do not produce a photometric opposition effect, i.e., a non-linear decrease of apparent magnitude near backscattering.
Two ubiquitous phenomena are observed near opposition for asteroids and other atmosphereless solar-system objects as well as for cometary and interplanetary dust: negative degree of linear polarization and opposition effect.
It describes how the shadow-hiding opposition effect is manifested in a fractally arranged surface, the important contribution of incoherent, multiply scattered light among small scatterers within a surface composed of aggregate grains and its amplification by backscatter interference.
Sometimes, the effect is referred to as the polarization opposition effect (POE) in order to distinguish it from the NPB, though a different origin for the NPB and POE is not obvious (e.g., Shkuratov et al., 2002; Zubko et al., 2008).
This is partly due to the brightness enhancement of the opposition effect; at quarter phase, the Moon is only one-tenth as bright, rather than half as bright, as at full moon.
On a solid surface, such as pavement, it is called an "opposition effect".
Except for a handful of lapdog leftist parties and a relentlessly harassed gaggle of human-rights groups, opposition, in effect, is outlawed.
