-
Skip These Ads
-
Skip These Ads|
|
 |
Click here and add this page to your favorites!
|
Encyclopedia Britannica - Main :: COR-CRE |
|
|
CORONA (Lat. for " crown ") , in astronomy, the exterior envelope of the sun, being beyond the photosphere and chromosphere, invisible in the telescope and unrecognized by the spectroscope, except during a total eclipse (see SUN; ECLIPSE). Corona Borealis, also known as the Corona septentrionalis, and the Northern Crown or Garland, is a constellation of the Northern hemisphere, mentioned by Eudoxus (4th cent. B.C.) and Aratus (3rd cent. B.C.). In the catalogues of Ptolemy
recent
Ptolemy
In physical science, coronae (or " glories ") are the coloured rings frequently seen closely encircling the sun or moon. Formerly classified by the ancient Greeks with halos, rainbows, &c., under the general group of "meteors," they came to receive considerable attention at the hands of Descartes, Christiaan Huygens, and Sir Isaac Newton ; but the correct explanation of coronae was reserved until the beginning of the loth century, when Thomas Young applied the theories of the diffraction and interference of light to this phenomenon. Prior to Young, halos and coronae had not been clearly differentiated ; they were both regarded as caused by the refraction of light by atmospheric moisture and ice, although observation had shown that important distinctions existed between these phenomena. Thus, while halos have certain definite radii, viz. 22 and 46, the radii of coronae vary very considerably ; also, halos are coloured red on the inside, whereas coronae are coloured red on the outside (see HALO). It has now been firmly established, both experimentally and mathematically, that coronae are due to diffraction by the minute particles of moisture and dust suspended in the atmosphere, and the radii of the rings depend on the size of the diffracting particles. (See DIFFRACTION OF LIGHT.) Other meteorological phenomena caused by the diffraction of light include the anthelia, and the chromatic rings seen encircling shadows thrown on a bank of clouds, mist or fog. These appear- ances differ from halos and coronae inasmuch as their centres are at the anti-solar point; they thus resemble the rainbow. The anthelia (from the Greek &vat, opposite, and ')Xtos, the sun) are coloured red on the inside, the outside being generally colour-less owing to the continued overlapping of many spectra. The diameter increases with the size of the globules making up the mist. The chromatic rings seen encircling the " spectre of the Brocken
The blue colour of the sky (q.v.), supernumerary rainbows, and the gorgeous sunsets observed of ter intense volcanic disturbances, when the atmosphere is charged with large quantities of extremely minute dust particles (e.g. Krakatoa), are also explicable by the diffraction of light. (See DuaT) See E. Mascart, Traite d'optique (18991903) ; J. Pernter, Meteorologische Optik (19021905). In architecture, the term " corona " is used of that part of a cornice which projects over the bed mould and constitutes the chief
wall
wall
apse or semicircular termination of the choir; as at Canterbury in the part called " Becket's crown." The large circular chandelier suspended in churches, of which the finest example is that given by Barbarossa to Aix-la-Chapelle, is often called a corona. The term is also used in botany of the crown-like appendage at the top of compound flowers
End of Article: CORONA (Lat. for " crown ") If you wish, you can link directly to this article.
<a href="http://jcsm.org/StudyCenter/Encyclopedia/COR_CRE/CORONA_Lat_for_crown_.html"> CORONA (Lat. for " crown ") </a> |
|
|
(Previous) COROMANDEL COAST |
(Next) CORONACH (a Gaelic word, from comh, with, and r... |
Jesus Christ Saves Ministries, P.O. Box 70696, Pasadena, CA 91117JCSM is a 501(c)(3), non-profit organization. Copyright © 1997-present. |
Free & Cheap Cell
Phones |
Cheap Long Distance
Phone Service Carriers |
Talk America Local Phone Service
|
Ztel & MCI - Unlimited Long Distance
Compare
Cell Phone Plans & Companies |
International Calling Cards & Prepaid Phone Cards |
Voice Over IP Broadband Internet Phone
Service | Wireless
Phone Plans & Cheap Cell Phones
|
_____________________________________________________________________________
Online First Aid and CPR Certification . The Online Christ Centered Ministries . The Skeptic's Annotated Bible: Corrected and Explained . The Inerrancy Discussion Board . Free Email Accounts . Home Equity Loans . JasonGastrich.com . The Missions, Apologetics, and Creation Bible Conference . Young Earth Creation Science . San Diego Music Lessons . 10,000 Wise Quotes and Spiritual Sayings . Gastrich.net . Maximizing the Internet: 12 Keys to Success . Louisiana Baptist University . NKJV Web Hosting and Services . Michael Newdow . San Diego Soccer Training . Christian Guitar Lessons . Jesus Christ Saves Ministries . Eternal Security
