They are the so-called forbidden lines—colors which an atom is extremely reluctant to radiate and will not radiate at all unless left undisturbed by collisions for seconds or minutes at a time (Armin J. Deutsch).
Useful english dictionary. 2012.
forbidden lines — ▪ physics in astronomical spectroscopy, bright emission lines in the spectra of certain nebulae (H II regions (H II region)), not observed in the laboratory spectra of the same gases, because on Earth the gases cannot be rarefied… … Universalium
Lakeer - Forbidden Lines — Infobox Film name = Lakeer Forbidden Lines imdb id = 0426075 writer = Ahmed Khan (screenplay) Shahab Khan (screenplay) Mehboob (dialogue) starring = Sunny Deol Sunil Shetty John Abraham Sohail Khan director = Ahmed Khan producer = Vivek Kumar… … Wikipedia
Forbidden mechanism — A forbidden mechanism or forbidden line is a concept in physics/chemistry. It is a spectral line emitted by atoms undergoing energy transitions not normally allowed by the selection rules of quantum mechanics. In chemistry, forbidden means… … Wikipedia
Forbidden City (nightclub) — The Forbidden City was a Chinese themed nightclub and cabaret in business from the late 1930s to the late 1950s at 363 Sutter Street (the former space is now renumbered 369 Sutter Street) in San Francisco s Chinatown.cite… … Wikipedia
nebula — nebular, adj. /neb yeuh leuh/, n., pl. nebulae / lee , luy /, nebulas. 1. Astron. a. Also called diffuse nebula. a cloud of interstellar gas and dust. Cf. dark nebula, emission nebula, reflection nebula … Universalium
Nebulium — Cat s Eye Nebula (NGC 6543) Nebulium was a proposed element found in a nebula by William Huggins in 1864. The strong green emission lines of the Cat s Eye Nebula, discovered using spectroscopy, led to the postulation that an as yet unknown… … Wikipedia
nebulium — /neuh byooh lee euhm/, n. Astron. a hypothetical element once thought to be present in emission nebulae because of certain unidentified spectral lines, now known to be forbidden transitions of oxygen and nitrogen ions. [1895 1900; NEBUL(A) + IUM] … Universalium
Ring Nebula — For the Ring Nebula in Barnard s Galaxy, see Ring Nebula (NGC 6822). The Ring Nebula M57, The Ring Nebula. Credit: NASA/STScI/AURA … Wikipedia
Astronomical spectroscopy — is the technique of spectroscopy used in astronomy. The object of study is the spectrum of electromagnetic radiation, including visible light, which radiates from stars and other celestial objects. Spectroscopy can be used to derive many… … Wikipedia
Donald Howard Menzel — by Babette Whipple Born April 11, 1901 … Wikipedia
