Gegenschein
Gegenschein (
Explanation
Like zodiacal light, gegenschein is sunlight scattered by interplanetary dust. Most of this dust orbits the Sun near the ecliptic plane, with a possible concentration of particles centered at the L2 point of the Earth–Sun system.[1]
Gegenschein is distinguished from zodiacal light by its high angle of reflection of the incident sunlight on the dust particles. It forms a slightly brighter elliptical spot of 8–10° across directly opposite the Sun within the dimmer band of zodiacal light and zodiac constellation.[2] The intensity of the gegenschein is relatively enhanced because each dust particle is seen at full phase,[3] having a difficult to measure apparent magnitude of +5 to +6, with a very low surface brightness in the +10 to +12 magnitude range.[4]
History
It is commonly stated that the gegenschein was first described by the French
Brorsen published the first thorough investigations of the gegenschein in 1854.[7] T. W. Backhouse discovered it independently in 1876, as did Edward Emerson Barnard in 1882.[8] In modern times, the gegenschein is not visible in most inhabited regions of the world due to light pollution.
See also
- Antisolar point
- Earth's shadow
- Heiligenschein
- Interplanetary dust cloud
- Kordylewski cloud
- Opposition surge, the apparent brightening of a coarse surface or an aggregate of many particles when illuminated from directly behind the observer
- Sylvanshine
References
- ^ Kopal, Zdeněk (June 14, 1962). "Communications on the Moon". New Scientist (291): 573.
- ^ "Take the Gegenschein Challenge". Sky & Telescope. 2015-10-14. Retrieved 2022-08-16.
- ISBN 0-7923-1365-8.
- ^ Dickinson, David (2016-02-03). "A Challenge in Visual Athletics: Hunting the Gegenschein". Universe Today. Retrieved 2022-08-16.
- ISBN 0-521-44489-6.
- ^ Blaschke, Jayme (17 August 2021). "'Celestial Sleuth' corrects historical record on gegenschein discovery". Texas State University Newsroom. Retrieved 15 September 2021.
- ISBN 1-4200-3344-1.
- ^ Ley, Willy (April 1961). "The Puzzle Called Gegenschein". For Your Information. Galaxy Science Fiction. pp. 74–84.
External links
- Gegenschein page on EarthSky.org
- Photos of gegenschein on SwissEduc.ch taken from Stromboli volcano
- "Zodiacal Light and the Gegenschein", an essay by J. E. Littleton
- NASA Astronomy Picture of the Day: The Gegenschein Over Chile (7 May 2008)
- Chisholm, Hugh, ed. (1911). . Encyclopædia Britannica (11th ed.). Cambridge University Press.