A planet that orbits a star other than the Sun. The first such planet to be discovered, in 1991, was found orbiting a pulsar, although most of the more than 100 extrasolar planets that have since been identified orbit normal stars. Many of them, known as hot Jupiters, are very large and revolve around their star in extremely close orbits, at less than the distance of Mercury’s orbit around the Sun. Other Jupiter-sized and larger planets have been found in highly eccentric orbits. Evidence suggests that extrasolar planets may be relatively common throughout the universe. In 2004, astronomers located the first extrasolar planet with an atmosphere containing oxygen and carbon. The planet, HD 209458b (also called Osiris), orbits a star 150 light-years from Earth. The apparent lack of terrestrial, Earth-sized planets among those that have so far been discovered may simply be the result of the much greater difficulty in identifying smaller, less massive bodies at such great distances. Also called exoplanet.
[ek-struh-sis-tuh-lee] /ˌɛk strəˈsɪs tə li/ noun, Pathology. 1. a premature contraction of the heart, resulting in momentary interruption of the normal heartbeat. extrasystole ex·tra·sys·to·le (ěk’strə-sĭs’tə-lē) n. An ectopic, usually premature contraction of the heart, resulting in momentary cardiac arrhythmia. Also called premature systole.
[ek-struh-tuh-res-tree-uh l] /ˌɛk strə təˈrɛs tri əl/ adjective 1. outside, or originating outside, the limits of the earth. noun 2. an extraterrestrial being: a science fiction novel about extraterrestrials conquering the earth. /ˌɛkstrətɪˈrɛstrɪəl/ adjective 1. occurring or existing beyond the earth’s atmosphere noun 2. (in science fiction) a being from beyond the earth’s atmosphere adj. […]
[ek-struh-ter-i-tawr-ee-uh l, -tohr-] /ˈɛk strəˌtɛr ɪˈtɔr i əl, -ˈtoʊr-/ adjective 1. beyond local jurisdiction, as the status of persons resident in a country but not subject to its laws. 2. pertaining to such persons. /ˌɛkstrəˌtɛrɪˈtɔːrɪəl/ adjective 1. beyond the limits of a country’s territory 2. of, relating to, or possessing extraterritoriality
- Extra time
noun 1. (sport) an additional period played at the end of a match, to compensate for time lost through injury or (in certain circumstances) to allow the teams to achieve a conclusive result