Albedo used in astronomy are the (V-band) geometric albedo (measuring brightness when illumination comes from directly behind the observer) and the Bond albedo (measuring total proportion of electromagnetic energy reflected). Their values can differ significantly, which is a common source of confusion. In detailed studies, the directional reflectance properties of astronomical bodies are often expressed in terms of the five Hapke parameters which semi-empirically describe the variation of albedo with phase angle, including a characterization of the opposition effect of regolith surfaces. The correlation between astronomical (geometric) albedo, absolute magnitude and diameter is: formula_7, where formula_8 is the astronomical albedo, formula_9
To be, or not to be to make a point about "extremism in defense of liberty." P.D. James' dystopian novel "The Children of Men" (1992) refers to expected or forced mass suicides of the elderly as "Quietus". The film adaptation "Children of Men" (2006) portrays a self-administered home suicide kit, labelled "Quietus". "Star Trek"'s was named after the "Undiscovered Country" line from this soliloquy. References are made to Shakespeare during the film including Klingon translations of his works and the use of the phrase "taH pagh, taHbe' ", roughly meaning "whether to continue, or not to continue [existence]." The book (and later film) "What Dreams May