Kordylewski cloud

Kordylewski began looking for a photometrically confirmable concentration of dust at the libration (Lagrangian) points in 1951.{{cite book |author=Dobbins, Thomas A. |title=Biographical Encyclopedia of Astronomers: Kordylewski, Kazimierz |url=https://books.google.com/books?id=t-BF1CHkc50C&pg=PA653 |date= 2007-09-18 |publisher=Springer |isbn=9780387304007}}{{Cite journal |last=Kordylewski |first=Kazimierz |date=1961 |title=Photographische Untersuchungen des Librationspunktes {{L5|nolink=yes}} im System Erde-Mond |trans-title=Photographic investigations of the libration point L5 in the Earth-Moon system |journal=Acta Astronomica |language=German |volume=11 |pages=165–169 |bibcode=1961AcA....11..165K |bibcode-access=free |number=3}}

After a change in method suggested by Josef Witkowski, the clouds were first seen by Kordylewski in 1956.{{cite conference| first = Rene| last = Laufer| author2 = Wilfried Tost| author3 = Oliver Zeile| author4 = Ralf Srama| author5 = Hans-Peter Roeser| date = February 2007| title = The Kordylewsky Clouds — an Example for a Cruise Phase Observation During the Lunar Mission BW1| conference = 11th ISU Annual International Symposium| location = Strasbourg| url = https://elib.dlr.de/49577/1/KordylewskiClouds-Paper.pdf| accessdate = 2018-10-28}} Between 6 March and 6 April 1961, he succeeded in photographing two bright patches near the {{L5}} Lagrange point. During the observation time, the patches hardly appeared to move relative to {{L5}}. The observations were taken from the mountain Kasprowy Wierch.

In 1967, J. Wesley Simpson made observations of the clouds using the Kuiper Airborne Observatory.{{sfn|Simpson|1967}}

In October 2018, the existence of the Kordylewski clouds was reported to have been confirmed by the Royal Astronomical Society, even though, earlier, in 1992, the Japanese Hiten space probe, which passed through the Lagrange points to detect trapped dust particles, did not find an obvious increase in dust levels above the density in surrounding space.

{{cite web

| title = Hiten

| website = NASA Space Science Data Coordinated Archive

| publisher = NASA

| url = https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1990-007A

| access-date = 8 March 2009}}

Hiten's failure to find the Kordylewski clouds does not rule out their existence, since the probe revolved around each Lagrange point for only one loop and could have missed the clouds.{{cite journal

| last1 = Wang

| first1 = Peng

| last2 = Jiang

| first2 = Xiao-Jun

| last3 = Hou

| first3 = Xi-Yun

| last4 = Zhang

| first4 = Li-Hua

| last5 = Jiang

| first5 = Li-Xiang

| last6 = Wang

| first6 = Jia-Qi

| last7 = Zhi

| first7 = Hui

| last8 = Jiao

| first8 = Zi-Long

| last9 = Li

| first9 = Tao

| last10 = Liu

| first10 = Ming-He

| last11 = Wang

| first11 = Jian-Feng

| display-authors = 1

| title = Ground- and Space-Based Observation of Kordylewski Clouds (Review Article)

| date = 27 February 2021

| journal = Space: Science & Technology

| volume = 2021

| page = 5

| url = https://downloads.spj.sciencemag.org/space/2021/6597921.pdf

| doi = 10.34133/2021/6597921

| doi-access = free

| id = 6597921

| access-date = 18 May 2022

}}

The decisive factor and change of methodology that has led to the unambiguous confirmation of the existence of these extremely faint and elusive celestial objects was using polarimetry, i.e. detecting them by their polarization patterns, not (primarily) by their brightness.

The Kordylewski clouds are a very faint phenomenon, comparable to the brightness of the gegenschein.{{Cite book |last=Covington |first=Michael A. |url=https://books.google.com/books?id=tzXv4WrvZ-EC&pg=PA32 |title=Astrophotography for the Amateur |date=1999 |publisher=Cambridge University Press |isbn=978-0-521-62740-5 |edition=2nd |pages=32–33 |ol=OL360409M}} 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 Lagrange points in ellipses of about 6 by 2 degrees.

• {{annotated link|Claimed moons of Earth}}
• {{annotated link|Trojan (celestial body)}}

{{reflist}}

• {{cite journal | title=Dust Cloud Moons of the Earth | journal=Physics Today | date=February 1967 | volume=20 | issue=2 | pages=39–46 | url=https://physicstoday.scitation.org/doi/10.1063/1.3034149 | url-access=subscription | doi=10.1063/1.3034149 |bibcode = 1967PhT....20b..39S | last1=Simpson | first1=J. Wesley }}
• {{cite journal | author= Winiarski, Maciej | title=Photographic Observations of the Clouds in the Neighbourhood of Libration Point {{L5|nolink=yes}} of the Earth–Moon System | journal=Earth, Moon, and Planets | volume=47 | issue=2 | date=1989 | pages=193–215 | doi=10.1007/BF00058142 | bibcode = 1989EM&P...47..193W | bibcode-access=free | s2cid=119559523 }}
• [http://nineplanets.org/hypo.html Hypothetical Planets]
• [http://www.rfreitas.com/Astro/SearchIcarus1983.htm 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.
• {{cite journal |url=https://ntrs.nasa.gov/search.jsp?R=19750038268&hterms=counterglow&qs=N%3D0%26Ntk%3DAll%26Ntt%3Dcounterglow%26Ntx%3Dmode%2520matchallpartial |title=Counterglow from the earth-moon libration points |last=Roach |first=J. R. |journal=Planetary and Space Science |volume=23 |pages=173–81 |date=January 1975 |issue=1 |access-date=2010-11-28 |doi=10.1016/0032-0633(75)90077-x|bibcode=1975P&SS...23..173R }}
• [https://www.sciencenews.org/article/earth-shimmering-space-dust-clouds-spotted-last One of Earth’s shimmering dust clouds has been spotted at last]

{{Earth}}

{{DEFAULTSORT:Kordylewski Cloud}}

Category:claimed moons of Earth

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Category:trojans (astronomy)

Category:Astronomical objects discovered in 1961