perihelion

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perihelion

(pĕr'əhē`lēən), point nearest the sun in the orbit of a body about the sun. See apsisapsis
(pl. apsides), point in the orbit of a body where the body is neither approaching nor receding from another body about which it revolves. Any elliptical orbit has two apsides.
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The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/

perihelion

(pe-ră-hee -kee-ŏn) The point in the orbit of a planet, comet, or artificial satellite in solar orbit that is nearest the Sun. The Earth is at perihelion on or about Jan. 3. The time of year at which Earth reaches perihelion varies over a period of about 20 000 years, getting progressively later in the year. The perihelion distance q , and aphelion distance Q , of major planets and asteroids are given in Tables 1 and 3, backmatter. See also advance of the perihelion.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

Perihelion

(religion, spiritualism, and occult)

Although they approximate circles, every orbit is elliptical. The point in a satellite’s orbit when it is nearest the Sun is called its perihelion (from the Greek peri, meaning “near” and helios, meaning “sun”).

The Astrology Book, Second Edition © 2003 Visible Ink Press®. All rights reserved.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Perihelion

 

the point nearest the sun in the orbit of a celestial body moving around the sun in a conic section—an ellipse, parabola, or hyperbola. Because of perturbations caused by the planets, perihelion positions change. For the planet closest to the sun, Mercury, a perihelion shift has been detected that arises in accordance with the more precise law of gravitation that follows from the general theory of relativity. The distance from perihelion to the center of the sun is called the perihelion distance.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

perihelion

[¦per·ə¦hēl·yən]
(astronomy)
That orbital point nearest the sun when the sun is the center of attraction.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

perihelion

The point in the orbit of a planet or a comet where it is nearest to the sun. The earth is at perihelion about January 1, when it is 3.4%, or about 3 million miles nearer to the sun than about July 1, when it is at aphelion—the point farthest from the sun. See aphelion.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved

perihelion

the point in its orbit when a planet or comet is nearest the sun
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005