first-event observations
81astronomy — /euh stron euh mee/, n. the science that deals with the material universe beyond the earth s atmosphere. [1175 1225; ME astronomie ( < AF) < L astronomia < Gk. See ASTRO , NOMY] * * * I Science dealing with the origin, evolution, composition,… …
82star — starless, adj. /stahr/, n., adj., v., starred, starring. n. 1. any of the heavenly bodies, except the moon, appearing as fixed luminous points in the sky at night. 2. Astron. any of the large, self luminous, heavenly bodies, as the sun, Polaris,… …
83Asteroid-impact avoidance — Planetary defense redirects here. For defending against alien invasion in fiction, see alien invasion. Artist s impression of a major impact event. The collision between Earth and an asteroid a few kilometres in diameter releases as much energy… …
84Paleontology — Palaeontology redirects here. For the scientific journal, see Palaeontology (journal). Paleontology studies the entire history of life on Earth. Paleontology (pronounced /ˌpælɪɒnˈtɒlədʒi/; British: palaeontology; from Greek: παλαιός… …
85Speed of light — The speed of light in the vacuum of free space is an important physical constant usually denoted by the letter c . [NIST and BIPM practice is to use c 0 for the speed of light in vacuum in accord with international standard ISO 31 5. See… …
86Mixture model — See also: Mixture distribution In statistics, a mixture model is a probabilistic model for representing the presence of sub populations within an overall population, without requiring that an observed data set should identify the sub population… …
87geomagnetic field — Magnetic field associated with the Earth. It is essentially dipolar (i.e., it has two poles, the northern and southern magnetic poles) on the Earth s surface. Away from the surface, the field becomes distorted. Most geomagnetists explain the… …
88Comet Shoemaker–Levy 9 — D/1993 F2 (Shoemaker–Levy) Image of Comet Shoemaker–Levy 9 fragments (total: 21), taken on May 17, 1994 Discovery Discovered by: Carolyn Shoemaker Eugene M. Shoemaker David Levy Discovery date …
89Cosmic microwave background radiation — CMB and Cosmic background radiation redirect here. For other uses see CMB (disambiguation) and Cosmic background (disambiguation). Physical cosmology …
90Corona — This article is about the astronomical term. For other uses, see Corona (disambiguation). During a total solar eclipse, the solar corona can be seen with the naked eye. A corona is a type of plasma atmosphere of the Sun or other celestial body,… …
