Kordylewski clouds are large concentrations of dust that exist at the L4 and L5 Lagrangian points of the Earth–Moon system. They were first reported by Polish astronomer Kazimierz Kordylewski in the 1960s, and confirmed to exist in October 2018.
Discovery and observation
The clouds were first seen by Kordylewski in 1956. Between 6 March and 6 April 1961, he succeeded in photographing two bright patches near the L5 libration point. During the observation time, the patches hardly appeared to move relative to L5. The observations were taken from the mountain Kasprowy Wierch.
In October 2018, the existence of the Kordylewski clouds was reported to have been confirmed, even though, earlier, in 2009, the Japanese Hiten space probe, which passed through the libration points to detect trapped dust particles, did not find an obvious increase in dust levels above the density in surrounding space.
The Kordylewski clouds are a very faint phenomenon, comparable to the brightness of the gegenschein. They are very difficult to observe from Earth but may be visible to the unaided eye in an exceptionally dark and clear night sky. Most claimed observations have been made from deserts, at sea, or from mountains. The clouds appear somewhat redder than the gegenschein, indicating that they may be made of a different kind of particle.
The Kordylewski clouds are located near the L4 and L5 Lagrange points of the Earth–Moon system. They are about 6 degrees in angular diameter. The clouds can drift up to 6 to 10 degrees from those points. Other observations suggest they move around the libration points in ellipses of about 6 by 2 degrees.
- Royal Astronomical Society (26 October 2018). "Earth's dust cloud satellites confirmed". EurekAlert!. Retrieved 27 October 2018.
- Slíz-Balogh, Judith; Barta, András; Horváth, Gábor (11 November 2018). "Celestial mechanics and polarization optics of the Kordylewski dust cloud in the Earth–Moon Lagrange point L5 – I. Three-dimensional celestial mechanical modelling of dust cloud formation". Monthly Notices of the Royal Astronomical Society. 480 (4): 5550–5559. doi:10.1093/mnras/sty2049. Retrieved 27 October 2018.
- Slíz-Balogh, Judith; Barta, András; Horváth, Gábor (1 January 2019). "Celestial mechanics and polarization optics of the Kordylewski dust cloud in the Earth–Moon Lagrange point L5 – Part II. Imaging polarimetric observation: new evidence for the existence of Kordylewski dust cloud". Monthly Notices of the Royal Astronomical Society. 482 (1): 762–770. doi:10.1093/mnras/sty2630. Retrieved 27 October 2018.
- Trimble, Virginia; et al. Biographical Encyclopedia of Astronomers: Kordylewski, Kazimierz. Biographical Encyclopedia of Astronomers. Retrieved 27 October 2018.
- Kordylewski, Kazimierz (1961). "L5". Acta Astronomica (in German). 11: 165–169. Bibcode:1961AcA....11..165K.
- Laufer, Rene; Wilfried Tost; Oliver Zeile; Ralf Srama; Hans-Peter Roeser (February 2007). The Kordylewsky Clouds — an Example for a Cruise Phase Observation During the Lunar Mission BW1 (pdf). 11th ISU Annual International Symposium. Strasbourg. Retrieved 2018-10-28.
- "Hiten". NASA. Retrieved 2009-03-08.
- Covington, Michael A. (1999). Astrophotography for the Amateur. Cambridge University Press. pp. 32–33. ISBN 0-521-62740-0.
- Kordylewski, Kazimierz (1961). "L5". Acta Astronomica. 11: 165–169. Bibcode:1961AcA....11..165K.
- "Dust Cloud Moons of the Earth". Physics Today. 20: 39–46. 1967. Bibcode:1967PhT....20b..39S. doi:10.1063/1.3034149.
- Winiarski, Maciej (1989). "L5". Earth, Moon, and Planets. 47 (2): 193–215. Bibcode:1989EM&P...47..193W. doi:10.1007/BF00058142.
- Hypothetical Planets
- A Search for Objects near the Earth–Moon Lagrangian Points, by Francisco Valdes and Robert A. Freitas Jr., did not find any objects at the Earth–Moon or Earth–Sun lagrange points, but this survey was not sensitive to diffuse clouds.
- Counterglow from the earth-moon libration points, by Roach, J. R., 2004-11-03, retrieved in 2010-11-28.