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Astro*Dictionary by Michael Erlewine

 

 

 

 

9 articles for "Perihelion"

Perihelion [Astro*Index]

From the Greek "near the Sun." The point in the orbit of a body that is nearest the center of the Sun. Opposite of Aphelion. Because of the mutual perturbation in the planets' orbits, the direction of each planet's perihelion/aphelion axis precesses. The rates are as follows (in arc seconds per century): Mercury, 574; Venus,???; Earth, 1165; [the rest of the planets???]. There has been close agreement between observation and prediction of this shift according to Einstein's theory of general relativity. William Lilly mentioned "the apsis of Mars . . . when it shall appear in Virgo" in his famous prediction of the great 1666 London fire: "Who shall expect less than a strange catastrophe of human affairs in commonwealth, monarchy and the Kingdom of England." [double check this; how much does Mars precess per century? is this what Lilly was referring to; how accurate and well-known were Kepler's (laws) measurements at that time?]

 

1990.0 Perihelia
  ME  17  GE  42
 VE  10  LE  48
 EA  12  CA  46
 MA  05  PI  51
 JU  15  AR  32
 SA  02  CA  37
 UR  18  VI  36
 NE  24  TA  55
 PL  13  SC  38

[ Neptune's p/a axis varies widely from the norm . . . ]

See also:
♦ Periapsis ♦ Apoapsis ♦ Aphelion ♦ Einstein ♦ Perturbation ♦ Kepler's Laws
Perihelion [Prima]

The word is of Greek origin and means "near the Sun." A planet's perihelion is the point in its orbit that is nearest the center of the Sun. It is opposite in meaning and position to aphelion.

Each planet's perihelion/aphelion axis precesses due to the mutual perturbation in the orbits of the planets.

See also:
♦ Periapsis ♦ Apoapsis ♦ Aphelion ♦ Einstein ♦ Perturbation ♦ Kepler's Laws
Perihelion [Munkasey M.]

The point for an orbiting Body where it is closest toits central focal point. The point where an orbiting body in the Solar System makes its closest approach to the Sun. For the Earth and the Sun this occurs at the Summer Solstice. This is also referred to as: "The Point of Perihelion".

See also:
♦ Periapsis ♦ Apoapsis ♦ Aphelion ♦ Einstein ♦ Perturbation ♦ Kepler's Laws
Perihelion [DeVore]

At the closest point to the Sun. v. Orbit.

See also:
♦ Orbit
Perihelion, Longitude of [Astro*Index]

The zodiacal longitude of a body's perihelion.

See also:
♦ Zodiacal Longitude ♦ Perihelion
Perihelion, Longitude of [Munkasey M.]

The Zodiacal Longitude of a Body's Perihelion.

See also:
♦ Astronomy ♦ Perihelion ♦ Perihelion Passage ♦ Perihelion to Node Angle
Perihelion to Node Angle [Munkasey M.]

The Clockwise (Eastward) angular measurefrom a Body's Perihelion to its Ascending Node.

See also:
♦ Astronomy ♦ Perihelion Passage ♦ Perihelion Longitude ♦ Perihelion
Perihelion Passage [Astro*Index]

The moment of time when a body is at its perihelion.

See also:
♦ Perihelion
Perihelion Passage [Munkasey M.]

Also referred to as "The Time of Perihelion Passage". The Sidereal Time at which the Body is at its Perihelion.

See also:
♦ Perihelion

 

Astro*Index Copyright © 1997 Michael Erlewine

 

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