CorrelationIn statistics, correlation or dependence is any statistical relationship, whether causal or not, between two random variables or bivariate data. Although in the broadest sense, "correlation" may indicate any type of association, in statistics it usually refers to the degree to which a pair of variables are linearly related. Familiar examples of dependent phenomena include the correlation between the height of parents and their offspring, and the correlation between the price of a good and the quantity the consumers are willing to purchase, as it is depicted in the so-called demand curve.
Gravitational lensA gravitational lens is a distribution of matter (such as a cluster of galaxies) or a point particle between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This effect is known as gravitational lensing, and the amount of bending is one of the predictions of Albert Einstein's general theory of relativity. Treating light as corpuscles travelling at the speed of light, Newtonian physics also predicts the bending of light, but only half of that predicted by general relativity.
Photometric systemIn astronomy, a photometric system is a set of well-defined passbands (or optical filters), with a known sensitivity to incident radiation. The sensitivity usually depends on the optical system, detectors and filters used. For each photometric system a set of primary standard stars is provided. A commonly adopted standardized photometric system is the Johnson-Morgan or UBV photometric system (1953). At present, there are more than 200 photometric systems.
Neutrino decouplingIn Big Bang cosmology, neutrino decoupling was the epoch at which neutrinos ceased interacting with other types of matter, and thereby ceased influencing the dynamics of the universe at early times. Prior to decoupling, neutrinos were in thermal equilibrium with protons, neutrons and electrons, which was maintained through the weak interaction. Decoupling occurred approximately at the time when the rate of those weak interactions was slower than the rate of expansion of the universe.
World eggThe world egg, cosmic egg or mundane egg is a mythological motif found in the cosmogonies of many cultures that is present in Proto-Indo-European culture and other cultures and civilizations. Typically, the world egg is a beginning of some sort, and the universe or some primordial being comes into existence by "hatching" from the egg, sometimes lain on the primordial waters of the Earth. Eggs symbolize the unification of two complementary principles (represented by the egg white and the yolk) from which life or existence, in its most fundamental philosophical sense, emerges.
PanguPangu (, ) is a primordial being and creation figure in Chinese mythology who separated heaven and earth, and his body later became geographic features such as mountains and rivers. The first writer to record the myth of Pangu was thought to be Xu Zheng during the Three Kingdoms period. However, his name was found in a tomb predating the Three Kingdoms period. In the beginning, there was nothing and the universe was in a featureless, formless primordial state. This primordial state coalesced into a cosmic egg for about 18,000 years.
Left–right political spectrumThe left–right political spectrum is a system of classifying political positions, ideologies and parties, with emphasis placed upon issues of social equality and social hierarchy. In addition to positions on the left and on the right, there are centrist and moderate positions, which are not strongly aligned with either end of the spectrum. On this type of political spectrum, left-wing politics and right-wing politics are often presented as opposed, although a particular individual or group may take a left-wing stance on one matter and a right-wing stance on another; and some stances may overlap and be considered either left-wing or right-wing depending on the ideology.
