Electromagnetic fieldAn electromagnetic field (also EM field or EMF) is a classical (i.e. non-quantum) field produced by moving electric charges. It is the field described by classical electrodynamics (a classical field theory) and is the classical counterpart to the quantized electromagnetic field tensor in quantum electrodynamics (a quantum field theory). The electromagnetic field propagates at the speed of light (in fact, this field can be identified as light) and interacts with charges and currents.
Seismic magnitude scalesSeismic magnitude scales are used to describe the overall strength or "size" of an earthquake. These are distinguished from seismic intensity scales that categorize the intensity or severity of ground shaking (quaking) caused by an earthquake at a given location. Magnitudes are usually determined from measurements of an earthquake's seismic waves as recorded on a seismogram. Magnitude scales vary on what aspect of the seismic waves are measured and how they are measured.
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.
Galactic astronomyGalactic astronomy is the study of the Milky Way galaxy and all its contents. This is in contrast to extragalactic astronomy, which is the study of everything outside our galaxy, including all other galaxies. Galactic astronomy should not be confused with galaxy formation and evolution, which is the general study of galaxies, their formation, structure, components, dynamics, interactions, and the range of forms they take.
