luminous radiation
71Lambert's cosine law — See also: Lambertian reflectance In optics, Lambert s cosine law says that the radiant intensity observed from a Lambertian surface or a Lambertian radiator is directly proportional to the cosine of the angle θ between the observer s line of… …
72Compact star — In astronomy, the term compact star (sometimes compact object) is used to refer collectively to white dwarfs, neutron stars, other exotic dense stars, and black holes. These objects are all small for their mass. The term compact star is often… …
73Hypergiant — A hypergiant (luminosity class 0) is a star with a tremendous mass and luminosity, showing signs of a very high rate of mass loss. CharacteristicsThe word “hypergiant” is commonly used as a loose term for the most massive stars found, even though …
74light — I (New American Roget s College Thesaurus) I adj. airy (see levity); frivolous, jesting, jocular, lightsome; giddy, dizzy, flighty; wanton; nimble, agile; flippant, pert, insouciant; humorous; trivial. See cheerfulness, unimportance, impurity,… …
75Wolf–Rayet star — Hubble Space Telescope image of nebula M1 67 around Wolf–Rayet star WR 124 Wolf–Rayet stars (often referred to as WR stars) are evolved, massive stars (over 20 solar masses initially), which are losing mass rapidly by means of a very strong… …
76Luminiferous aether — The luminiferous aether: it was hypothesised that the Earth moves through a medium of aether that carries light In the late 19th century, luminiferous aether or ether, meaning light bearing aether, was the term used to describe a medium for the… …
77Gamma ray burst — [ GRB 990123 taken on January 23, 1999. The burst is seen as a bright dot denoted by a square on the left, with an enlarged cutout on the right. The object above it with the finger like filaments is the originating galaxy. This galaxy seems to be …
78Radio galaxy — Radio galaxies and their relatives, radio loud quasars and blazars, are types of active galaxy that are very luminous at radio wavelengths (up to 1038 W between 10 MHz and 100 GHz). The radio emission is due to the synchrotron process. The… …
79Convection zone — An illustration of the structure of the Sun: 1. Core 2. Radiative zone 3. Convective zone 4. Photosphere 5. Chromosphere 6. Corona 7. Sunspot 8. Granules 9. Prominence …
80Astronomy — (from the Greek words astron (ἄστρον), star , and nomos (νόμος), law ) is the scientific study of celestial objects (such as stars, planets, comets, and galaxies) and phenomena that originate outside the Earth s atmosphere (such as the cosmic… …
