perihelion

the point in its orbit when a planet or comet is nearest the sun

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

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”).

perihelion

[¦per·ə¦hēl·yən]

(astronomy)

That orbital point nearest the sun when the sun is the center of attraction.

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.

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 It might be outdated or ideologically biased.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.

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References in periodicals archive

Perihelion's story is one with Faizan's, who has been its only constant member since inception.

A young idealist codes his way to his dreams

And, second, he says, 12 objects is a tiny sample--the apparent perihelion clustering may just be an illusion caused by where researchers point their telescopes.

Shadow planet: strange orbits in the Kuiper belt revive talk of a Planet X in the solar system

If that happens to ISON before perihelion day, don't expect much of anything at all to be visible afterward.

Comet ISON: spectacle or speck? The finest comet in years may glow in the east at down in December 2013--unless it crubles away first

Before Lovejoy, none of the sungrazers seen by SOHO has survived their perihelion passage.

Comet lovejoy, the great Christmas comet of 2011

As well as ante-post favourite Moonstone, O'Brien has declared Adored, Gentle On My Mind, Honoria, Perihelion and Ice Queen as he bids to add to the recent wins of Alexandrova (2006) and Peeping Fawn (2007) in the 12-furlong Classic.

O'Brien has six in Oaks

Earlier, Perihelion rounded off another excellent day for Aidan O'Brien by winning the opening maiden under Seamus Heffernan.

Horse Racing: Eritrea books Galway ticket

These lead to a Keplerian orbit in three dimensions, which gives the observed values of perihelion precession and bending of light by a massive object.

A classical model of gravitation

The point where a planetCOs orbit is nearest to the Sun is called the perihelion. The point furthest away from the Sun is called aphelion.

Orbits

Sarah Law's third book of poetry, Perihelion, is full of sequences: a twenty-sonnet sequence about monsters, another ten sonnets about tai chi, and forty ekphrastic poems about Italian Renaissance art and architecture.

Perihelion

Opp, Ala., Gives OK to Perihelion Global's Planned Biofuel Refinery