Earth and Space News

Wednesday, November 23, 2011

Nov. 25, 2011, Partial Solar Eclipse Belongs to Saros Series 123

Summary: The Friday, Nov. 25, 2011, partial solar eclipse belongs to Saros cycle 123, a series of 70 similar solar eclipses.

Partial solar eclipse of April 29, 1074, opened Saros solar series 123’s lineup of 70 solar eclipses: "Permission is freely granted to reproduce this data when accompanied by an acknowledgment, Eclipse Predictions by Fred Espenak (NASA's GSFC)," via NASA Eclipse Web Site

The Friday, Nov. 25, 2011, partial solar eclipse belongs to Saros cycle 123, which comprises 70 solar eclipses with similar geometries.

November’s partial solar eclipse begins Friday, Nov. 25, 2011, at 04:23:15.5 Universal Time, according to the NASA Eclipse Web Site. Greatest eclipse takes place at 06:20:16.6 UT. Greatest eclipse refers to the instant of the closest passage of the lunar shadow cone’s axis to Earth’s center. The eclipse ends at 08:17:15.6 UT.

November 2011’s partial solar eclipse numbers as 53 in the lineup of 70 solar eclipses that compose Saros cycle 123. Similar geometries identify the 70 solar eclipses as a family, known as a series.

The NASA Eclipse Web Site describes Saros 123 solar eclipses as sharing the geometry of occurring at the moon’s ascending node. With each succeeding eclipse in Saros 123, the lunar movement is southward of the ascending node.

A pair of ascending and descending nodes announce the intersections of Earth’s orbit by the moon’s orbit. The approximately 5.1 degree tilt of the moon’s orbit with respect to Earth’s orbit explains the two nodes. The ascending node links with the lunar orbital crossing to the north of Earth’s orbit. The descending node associates with the lunar orbital crossing to the south of Earth’s orbit.

The Saros cycle of approximately 6,585.3 days (18 years 11 days 8 hours) governs the periodicity and recurrence of solar eclipses. Each Saros series comprises 70 or more eclipses that have a typical timeline of over 12 to 13 centuries.

Saros solar series 123 lasts for 1,224.08 years, according to the NASA Eclipse Web Site. The series covers 14 centuries. Saros solar series 123 encompasses the 11th through 24th centuries.

Solar eclipses in Saros series 123 follows a sequence order of six partial solar eclipses, 27 annular solar eclipses, three hybrid solar eclipses, 14 total solar eclipses and 20 partial solar eclipses. Annular solar eclipses contribute the most number of eclipses to Saros series 123, with a total of 27 occurrences. Partial solar eclipses are the second most frequent, with a total of 26 occurrences.

The partial solar eclipse of Wednesday, April 29, 1074, opened Saros solar series 123. This Northern Hemisphere event stages its greatest eclipse, with coordinates of 62.2 north at 39.8 east, over Arkhangelsk Oblast in northwestern Russia.

The partial solar eclipse of Friday, May 31, 2318, will close Saros solar series 123. This Southern Hemisphere event's greatest eclipse, with coordinates of 64.2 south at 131.2 east, will take place over the Southern Ocean, northeast of East Antarctica's Concordia Station.

The partial solar eclipse of Friday, Nov. 25, 2011, numbers as third in Saros solar series 123’s closing sequence of 20 partial solar eclipses. This Southern Hemisphere event experiences its greatest eclipse, with coordinates of 68.6 south at 82.4 west, over the Southern Ocean, northwest of the Antarctic Peninsula's Alexander Island.

A partial solar eclipse on Saturday, Nov. 13, 1993, was the immediate predecessor of the November 2011 partial solar eclipse in Saros solar series 123. This Southern Hemisphere event's greatest eclipse, with coordinates of 69.6 south at 58.3 east, occurred over East Antarctica, northwest of Davis Station.

The November 1993 partial solar eclipse occurred as second in Saros solar series 123’s closing sequence of 20 partial solar eclipses. The event numbered 52 in the series’ lineup of 70 solar eclipses.

A partial solar eclipse on Wednesday, Dec. 5, 2029, succeeds the November 2011 partial solar eclipse in Saros solar series 123. This Southern Hemisphere event will stage its greatest eclipse, with coordinates of 67.5 south at 135.7 east, over East Antarctica, northeast of Concordia Station.

The December 2029 partial solar eclipse will occur as the fourth of 20 partial solar eclipses in Saros solar series 123’s closing sequence. This eclipse numbers 54 in the series’ lineup of 70 solar eclipses.

The takeaway for the Friday, Nov. 25, 2011, partial solar eclipse is that the astronomical event appears as number 53 in Saros solar series 123’s lineup of 70 solar eclipses and as the third occurrence in the series’ closing sequence of 20 partial solar eclipses.

Partial solar eclipse of Friday, May 31, 2318, will close Saros solar series 123’s lineup of 70 solar eclipses: "Permission is freely granted to reproduce this data when accompanied by an acknowledgment, Eclipse Predictions by Fred Espenak (NASA's GSFC)," via NASA Eclipse Web Site

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Espenak, Fred. “Eclipses and the Saros.” NASA Eclipse Web Site > Solar Eclipses > Solar Eclipse Catalogs > Saros Catalog of Solar Eclipses: Saros 0-180.
Available via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/SEsaros/SEsaros.html

Espenak, Fred. “Partial 1074 Apr 29.” NASA Eclipse Web Site > Solar Eclipses > Solar Eclipse Catalogs: Saros Catalog of Solar Eclipses Saros 0-180 > Eclipses and the Saros: Return to Catalog of Solar Eclipse Saros Series > Catalog of Solar Eclipse Saros Series: Solar Eclipses of Saros 0 to 180: Summary of Saros Series 100 to 125: 123 > Saros Series Catalog of Solar Eclipses: Saros Series 123: Catalog of Solar Eclipses of Saros 123: 07299 -33 1074 Apr 29.
Available via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/5MCSEmap/1001-1100/1074-04-29.gif

Espenak, Fred. “Partial 1993 Nov 13.” NASA Eclipse Web Site > Solar Eclipses > Solar Eclipse Catalogs: Saros Catalog of Solar Eclipses Saros 0-180 > Eclipses and the Saros: Return to Catalog of Solar Eclipse Saros Series > Catalog of Solar Eclipse Saros Series: Solar Eclipses of Saros 0 to 180: Summary of Saros Series 100 to 125: 123 > Saros Series Catalog of Solar Eclipses: Saros Series 123: Catalog of Solar Eclipses of Saros 123: 09494 18 1993 Nov 13.
Available via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/5MCSEmap/1901-2000/1993-11-13.gif

Espenak, Fred. “Partial 2011 Nov 25.” NASA Eclipse Web Site > Solar Eclipses > Solar Eclipse Catalogs: Saros Catalog of Solar Eclipses Saros 0-180 > Eclipses and the Saros: Return to Catalog of Solar Eclipse Saros Series > Catalog of Solar Eclipse Saros Series: Solar Eclipses of Saros 0 to 180: Summary of Saros Series 100 to 125: 123 > Saros Series Catalog of Solar Eclipses: Saros Series 123: Catalog of Solar Eclipses of Saros 123: 09534 19 2011 Nov 25.
Available via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/5MCSEmap/2001-2100/2011-11-25.gif

Espenak, Fred. “Partial 2029 Dec 05.” NASA Eclipse Web Site > Solar Eclipses > Solar Eclipse Catalogs: Saros Catalog of Solar Eclipses Saros 0-180 > Eclipses and the Saros: Return to Catalog of Solar Eclipse Saros Series > Catalog of Solar Eclipse Saros Series: Solar Eclipses of Saros 0 to 180: Summary of Saros Series 100 to 125: 123 > Saros Series Catalog of Solar Eclipses: Saros Series 123: Catalog of Solar Eclipses of Saros 123: 09574 20 2029 Dec 05.
Available via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/5MCSEmap/2001-2100/2029-12-05.gif

Espenak, Fred. “Partial 2318 May 31.” NASA Eclipse Web Site > Solar Eclipses > Solar Eclipse Catalogs: Saros Catalog of Solar Eclipses Saros 0-180 > Eclipses and the Saros: Return to Catalog of Solar Eclipse Saros Series > Catalog of Solar Eclipse Saros Series: Solar Eclipses of Saros 0 to 180: Summary of Saros Series 100 to 125: 123 > Saros Series Catalog of Solar Eclipses: Saros Series 123: Catalog of Solar Eclipses of Saros 123: 10260 36 2318 May 31.
Available via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/5MCSEmap/2301-2400/2318-05-31.gif

Espenak, Fred. “Partial Solar Eclipse of 1074 Apr 29.” EclipseWise > Solar Eclipses > Solar Eclipse Links > Six Millennium Catalog of Solar Eclipses -2999 to 3000 (3000 BCE to 3000 CE) > 1001 to 1100 (1001 CE to 1100 CE).
Available via EclipseWise @ http://eclipsewise.com/solar/SEprime/1001-1100/SE1074Apr29Pprime.html

Espenak, Fred. “Partial Solar Eclipse of 1993 Nov 13.” EclipseWise > Solar Eclipses > Solar Eclipse Links > Six Millennium Catalog of Solar Eclipses -2999 to 3000 (3000 BCE to 3000 CE) > 1901 to 2000 (1901 CE to 2000 CE).
Available via EclipseWise @ http://eclipsewise.com/solar/SEprime/1901-2000/SE1993Nov13Pprime.html

Espenak, Fred. “Partial Solar Eclipse of 2011 Nov 25.” EclipseWise > Solar Eclipses > Solar Eclipse Links > Six Millennium Catalog of Solar Eclipses -2999 to 3000 (3000 BCE to 3000 CE) > 2001 to 2100 (2001 CE to 2100 CE).
Available via EclipseWise @ http://eclipsewise.com/solar/SEprime/2001-2100/SE2011Nov25Pprime.html

Espenak, Fred. “Partial Solar Eclipse of 2029 Dec 05.” EclipseWise > Solar Eclipses > Solar Eclipse Links > Six Millennium Catalog of Solar Eclipses -2999 to 3000 (3000 BCE to 3000 CE) > 2001 to 2100 (2001 CE to 2100 CE).
Available via EclipseWise @ http://eclipsewise.com/solar/SEprime/2001-2100/SE2029Dec05Pprime.html

Espenak, Fred. “Partial Solar Eclipse of 2318 May 31.” EclipseWise > Solar Eclipses > Solar Eclipse Links > Six Millennium Catalog of Solar Eclipses -2999 to 3000 (3000 BCE to 3000 CE) > 2301 to 2400 (2301 CE to 2400 CE).
Available via EclipseWise @ http://eclipsewise.com/solar/SEprime/2301-2400/SE2318May31Pprime.html

Espenak, Fred. “Partial Solar Eclipse of July 01.” NASA Eclipse Web Site > Solar Eclipses > Solar Eclipses: Past and Future.
Available via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/OH/OH2011.html

Espenak, Fred. “Saros Series 123.” NASA Eclipse Web Site > Solar Eclipses > Solar Eclipse Catalogs > Saros Catalog of Solar Eclipses: Saros 0-180.
Available via NASA Eclipse Web Site @ https://eclipse.gsfc.nasa.gov/SEsaros/SEsaros123.html

Marriner, Derdriu. “First of Four 2011 Partial Solar Eclipses Happens Tuesday, Jan. 4.” Earth and Space News. Wednesday, Dec. 29, 2010.
Available @ https://earth-and-space-news.blogspot.com/2010/12/first-of-four-2011-partial-solar.html

Marriner, Derdriu. “Fourth of Four 2011 Partial Solar Eclipses Happens Friday, Nov. 25.” Earth and Space News. Wednesday, Nov. 16, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/11/fourth-of-four-2011-partial-solar.html

Marriner, Derdriu. “Jan. 4, 2011, Partial Solar Eclipse Belongs to Saros Series 151.” Earth and Space News. Wednesday, Dec. 22, 2010.
Available @ https://earth-and-space-news.blogspot.com/2011/01/jan-4-2011-partial-solar-eclipse.html

Marriner, Derdriu. “July 1, 2011, Partial Solar Eclipse Opens Saros Series 156.” Earth and Space News. Wednesday, June 22, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/06/july-1-2011-partial-solar-eclipse-opens.html

Marriner, Derdriu. “June 1, 2011, Partial Solar Eclipse Belongs to Saros Series 118.” Earth and Space News. Wednesday, June 1, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/06/june-1-2011-partial-solar-eclipse.html

Marriner, Derdriu. “Second of Four 2011 Partial Solar Eclipses Happens Wednesday, June 1.” Earth and Space News. Wednesday, May 25, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/05/second-of-four-2011-partial-solar.html

Smith, Ian Cameron. “Partial Solar Eclipse of 5 Dec, 2029 AD.” Moon Blink > Hermit Eclipse > Eclipse Database > Full Solar Catalog > 2001-3000 AD > 2001 AD > 2021-2040 AD.
Available @ https://moonblink.info/Eclipse/eclipse/2029_12_05

Smith, Ian Cameron. “Partial Solar Eclipse of 13 Nov, 1993 AD.” Moon Blink > Hermit Eclipse > Eclipse Database > Full Solar Catalog > 1001-2000 AD > 1901 AD > 1981-2000 AD.
Available @ https://moonblink.info/Eclipse/eclipse/1993_11_13

Smith, Ian Cameron. “Partial Solar Eclipse of 25 Nov, 2011 AD.” Moon Blink > Hermit Eclipse > Eclipse Database > Full Solar Catalog > 2001-3000 AD > 2001 AD > 2001-2020 AD.
Available @ https://moonblink.info/Eclipse/eclipse/2011_11_25

Smith, Ian Cameron. “Partial Solar Eclipse of 29 Apr, 1074 AD.” Moon Blink > Hermit Eclipse > Eclipse Database > Full Solar Catalog > 1001-2000 AD > 1061-1080 AD.
Available @ https://moonblink.info/Eclipse/eclipse/1074_04_29

Smith, Ian Cameron. “Partial Solar Eclipse of 31 May, 2318 AD.” Moon Blink > Hermit Eclipse > Eclipse Database > Full Solar Catalog > 2001-3000 AD > 2301 AD > 2301-2320 AD.
Available @ https://moonblink.info/Eclipse/eclipse/2318_05_31

Wednesday, November 16, 2011

Fourth of Four 2011 Partial Solar Eclipses Happens Friday, Nov. 25

Summary: The fourth of four 2011 partial solar eclipses happens Friday, Nov. 25, with Antarctica’s high latitudes favored for the path of visibility.

Earth visibility chart and eclipse statistics for partial solar eclipse of Nov. 25, 2011: "Permission is freely granted to reproduce this data when accompanied by an acknowledgment, Eclipse Predictions by Fred Espenak, NASA GSFC Emeritus," via NASA Eclipse Web Site

The fourth of four 2011 partial solar eclipses happens Friday, Nov. 25, as a Southern Hemisphere event, with the path of visibility especially favoring Antarctica and the Southern Ocean, where summer’s 24-hour midnight sun reigns south of the Antarctic Circle.

Oceanically, the path of visibility also includes the South Atlantic, South Indian and South Pacific oceans. In addition to but also including the South Atlantic, South Indian and South Pacific oceans. Continentally, the Republic of South Africa on Africa’s southern tip and Tasmania, south of the Australian mainland, fall within the event’s path of visibility. Most of the southwestern Pacific island nation of New Zealand participates in the path of visibility for the fourth of four 2011 partial solar eclipses.

The moon’s passage between Earth and the sun occasions a solar eclipse for observers on Earth. A partial solar eclipse concerns a partial block or obscuration of the sun’s image by the moon.

First contact of the moon’s penumbral shadow with Earth’s surface announces the start of the fourth of four 2011 partial solar eclipses. The penumbra, which is the shadow’s lighter, outer region, first touches Earth’s surface Friday, Nov. 25, at 4:23:15.5 Universal Time (Friday, Nov. 25, at 6:23 a.m. South Africa Standard Time; Friday, Nov. 25, at 9:23 a.m. Davis Time in Davis Station, Antarctica; Thursday, Nov. 24, at 11:23 p.m. Eastern Daylight Time). P1 is the astronomical designation for the instant of first contact between Earth’s surface and the moon’s penumbral shadow.

The moon’s penumbral shadow first makes contact with water on Earth’s surface. The South Atlantic Ocean off South Africa’s west coast claims the November 2011 event’s first touch.

On the NASA Eclipse Web Site, retired astrophysicist Fred Espenak, known as “Mr. Eclipse,” gives 04:28 UT (6:28 a.m. SAST) as the eclipse start time for Cape Town, Western Cape Province, western South Africa. The eclipse begins at 05:31 UT (10:31 a.m. DAVT) for Davis Station in East Antarctica. Dunedin on the southeast coast of New Zealand’s South Island experiences an eclipse start time of 07:03 UT (8:03 p.m. New Zealand Daylight Time). The eclipse starts at 07:30 UT (6:03 p.m. Australian Eastern Daylight Time) for Hobart, on the southeast coast of the Australian island state of Tasmania.

Greatest eclipse happens Friday, Nov. 25, at 06:20:16.6 UT (Friday, Nov. 25, at 1:20 a.m. EDT). Greatest eclipse signals the instant of closest passage of the axis of the lunar shadow cone to Earth’s center.

The instant of greatest eclipse takes place near the coast of West Antarctica, also known as Lesser Antarctica). Fred Espenak places the passage of the lunar shadow axis at only 330 kilometers (205.05 miles) above Earth’s surface at the instant of greatest eclipse.

The fourth of four 2011 partial solar eclipses ends with the lunar penumbra’s last contact with Earth’s surface. Last contact occurs Friday, Nov. 25, at 08:17:15.6 UT (3:17 a.m. EDT). P4 is the astronomical designation for the instant of last contact between Earth’s surface and moon’s penumbral shadow, as the moon exits from the sun’s edge, known as limb.

“Mr. Eclipse” gives 05:08 UT (7:08 a.m. SAST) as the eclipse end time for Port Elizabeth, Eastern Cape Province, southeastern South Africa. The November 2011 partial solar eclipse ends at 08:08 UT (7:08 p.m. AEDT) for Tasmania’s capital city of Hobart. Australia’s Casey Station on the northern side of eastern Antarctica’s Bailey Peninsula clocks the eclipse’s end at 07:45 UT (6:45 p.m. CAST -- Casey Standard Time).

Sunset prevents New Zealanders from viewing the November 2011 partial solar eclipse in its entirety. By greatest eclipse, the sun is already close to the horizon. Time And Date web site recommends that New Zealanders find observation sites with free sight to the west-southwest for greatest eclipse visibility. Within one to 30-plus minutes of the greatest eclipse, the sun slips below the horizon and effectively ends the event for New Zealanders.

The November 2011 partial solar eclipse belongs to Saros 123. The Saros cycle recognizes families, known as series, for solar eclipses as well as for lunar eclipses. A Saros cycle approximates 6,585.3 days (18 years 11 days 8 hours).

The fourth of four 2011 partial solar eclipse takes place about four and three-fourths months after the year’s third partial solar eclipse, which occurred Friday, July 1. The November 2011 event shares its predecessor’s favoring of the Southern Hemisphere for visibility.

The November 2011 event closes the year’s lineup of four partial solar eclipses. The year’s first and second partial solar eclipses happened Tuesday, Jan. 4, and Wednesday, June 1, respectively. Both eclipses favored the Northern Hemisphere.

A total lunar eclipse midway through the year, on Wednesday, June 15, and a second and final total lunar eclipse on Saturday, Dec. 10, contribute to 2011’s rare 4:2 eclipse combination. In the 21st century, 2011 numbers among only six years featuring the 4:2 combination: 2011, 2029, 2047, 2065, 2076 and 2094.

Observers along the path of visibility should avoid direct viewing of the partial solar eclipse. Safe viewing of partial solar eclipses calls for use of proper equipment and following of proper techniques.

The takeaway for the fourth of four 2011 partial solar eclipses, which happens Friday, Nov. 25, is the event’s favoring of the Southern Hemisphere, focused on Antarctica, for visibility.

animation of Nov. 25, 2011, solar eclipse: A.T. Sinclair/NASA Goddard Space Flight Center (GSFC), Public Domain, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

animation of Nov. 25, 2011, solar eclipse: A.T. Sinclair/NASA Goddard Space Flight Center (GSFC), Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:SE2011Nov25P.gif

For further information:

Espenak, Fred. “Eclipses During 2011.” NASA Eclipse Web Site > Observer’s Handbook.
Available @ https://eclipse.gsfc.nasa.gov/OH/OH2011.html

Espenak, Fred. “Five Millennium Catalog of Solar Eclipses: 2001 to 2100 (2001 CE to 2100 CE).” NASA Eclipse Web Site > Solar Eclipses.
Available @ https://eclipse.gsfc.nasa.gov/SEcat5/SE2001-2100.html

Espenak, Fred. “Greatest Eclipse.” NASA Eclipse Web Site > Glossary of Solar Eclipse Terms.
Available @ https://eclipse.gsfc.nasa.gov/SEhelp/SEglossary.html

Espenak, Fred. “Table 4 -- Local Circumstances for Partial Solar Eclipse of 2011 November 25.” NASA Eclipse Web Site > Observer’s Handbook > Observer’s Handbook Tables > Observer’s Handbook 2011.
Available @ https://eclipse.gsfc.nasa.gov/OH/OHtables/OH2011-Tab04.pdf

Littmann, Mark; Ken Willcox; Fred Espenak. “Observing Solar Eclipses Safely.” MrEclipse > Totality.
Available @ http://www.mreclipse.com/Totality2/TotalityCh11.html

Marriner, Derdriu. “First of Two 2011 Total Lunar Eclipses Happens Wednesday, June 15.” Earth and Space News. Wednesday, June 8, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/06/first-of-two-2011-total-lunar-eclipses.html

Marriner, Derdriu. “Third of Four 2011 Partial Solar Eclipses Happens Friday, July 1.” Earth and Space News. Wednesday, June 29, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/06/third-of-four-2011-partial-solar.html

“November 25, 2011 -- Partial Solar Eclipse.” TimeAndDate > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/solar/2011-november-25

“November 25, 2011 -- Partial Solar Eclipse -- Davis, Antarctica (Davis Base, Vestfold Hills.” Time And Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/in/antarctica/davis?iso=20111125

"November 25, 2011 -- Partial Solar Eclipse -- Dunedin, New Zealand (Ōtepoti)." Time And Date > Sun & Moon > Eclipses.
Available @ https://www.timeanddate.com/eclipse/in/new-zealand/dunedin?iso=20111125

“Time Zone Changes in Antarctica in 2010.” Time And Date > Time Zones > Time Zone News.
Available @ https://www.timeanddate.com/news/time/antartica-time-changes-2010.html

Wednesday, November 9, 2011

Herschel Crater Appears As Dot Eaten by Pac-Man in Mimas Temperature Map

Summary: A Mimas temperature map shows unexpected coldness around Herschel Crater, according to data obtained Feb. 13, 2010, by Cassini-Huygens spacecraft.

Detail of Mysterious Temperatures on Mimas, released March 29, 2010, shows pareidolic Pac-Man and Pac-Dot images of Saturnian moon Mimas and its dominant crater, Herschel, in temperature map (above) created from data gathered Feb. 13, 2010, by the Cassini-Huygens spacecraft’s composite infrared spectrometer (CIRS); lower image incorporates temperature map into mosaic of images captured on previous flybys: courtesy NASA / JPL (Jet Propulsion Laboratory) / SWRI (Southwest Research Institute) / SSI (Space Science Institute), via NASA Goddard Space Flight Center (GSFC) pages

Herschel Crater appears as a dot eaten by Pac-Man in a Mimas temperature map created by data gathered during the Cassini-Huygens spacecraft’s closest-ever approach of the Saturnian moon on Feb. 13, 2010.

“The highest-resolution-yet temperature map and images of Saturn’s icy moon Mimas obtained by NASA’s Cassini spacecraft reveal surprising patterns on the surface of the small moon, including unexpected hot regions that resemble ‘Pac-Man’ eating a dot, and striking bands of light and dark in crater walls,” writes Robert Garner, lead web editor at the National Aeronautics and Space Administration’s (NASA) Goddard Space Flight Center (GSFC) in Greenbelt, Maryland, in his March 29, 2010, feature for the NASA GSFC webpage.

The data from Cassini-Huygens spacecraft’s composite infrared spectrometer (CIRS) defied GSFC scientists’ expectations of smooth temperature variations with an early afternoon peak near the moon’s equator. Instead, the CIRS-generated map identifies a morning peak, color coded in yellows (warmest), oranges and reds, along the moon’s trailing edge. Colder temperatures, color coded in purples and blues (coldest), prevail to the peak’s east, in the moon’s leading hemisphere dominated by equator-straddling Herschel Crater. Garner gives a temperature range with the highest at around 77 Kelvin (minus 294 degrees Fahrenheit) and the lowest at around 77 Kelvin (minus 320 degrees Fahrenheit).

The sharply defined peak’s sidewise v-shape, which radiates from the equator to encompass both polar regions, resembles Pac-Man’s wide open mouth. Hershel Crater poises motionless, as a doomed Pac-Dot, in front of Pac-Man’s mouth, midway between the maze arcade game hero’s greatly extended jaws.

Herschel Crater stands out as a mainly purplish circle against a bluish background of colder temperatures. Oppositely extreme temperatures, positioned oppositely on a diagonal axis through the crater’s central peaks, interrupt the crater’s overall purplishness. A bluish dot of colder temperatures lies inside the crater’s northwestern rim. An orangish-reddish dot sits as a pocket of warmer temperatures inside the crater’s southeastern rim.

“Even though we can’t explain the observed pattern of surface temperatures on Mimas, the giant Herschel crater is a leading suspect,” reports Michael Flasar, NASA Goddard Space Flight Center’s composite infrared spectrometer (CIRS) principal investigator. “The energy of impact that created it several billion years ago has been estimated to be one-seventh of Mimas’s own gravitational energy. Anything much larger would likely have torn the moon apart. We really would like to see if there is an anomalous temperature pattern on the other side of Herschel, which has been observed so closely.”

Herschel Crater’s tall walls help to explain the generally warmer temperatures within the crater. Herschel’s 5-kilometer- (3-mile-) high walls operate as heat traps for the crater’s interior.

Warmer temperatures also characterize Herschel Crater’s environs. The composite infrared spectrometer’s temperature map reveals purplish regions extending outward from the crater, especially from the western, eastern and southern portions of the rim.

Yet the temperature map baffles its interpreters. “We suspect the temperatures are revealing differences in texture on the surface,” observes John Spencer, a CIRS co-investigator based at Southwest Research Institute in Boulder, Colorado. “It’s maybe something like the difference between old, dense snow and freshly fallen powder.”

Garner explains that denser ice’s quick conduction of the sun’s heat away from the surface accounts for daytime coldness in icy areas. Powdery ice’s insulating ability promotes warmed surfaces by trapping solar heat at the surface.

Spencer suspects that a much higher thermal inertia exists in Mimas’ colder regions, according to an interview posted March 30, 2010, on NASA Science Mission Directorate’s Solar System Exploration website by Cassini lead propulsion engineer Todd J. Barber. “In this case,” writes Barber, “heat could soak into the Mimas interior more easily rather than raise the temperature of the surface. The shocking inference is that the thermal conductivity has to be at least ten times greater in the cold regions vs. the warmer regions . . .”

Garner reports Spencer’s observation that, even with the surface texture variation hypothesis, scientists are still struggling to understand the Mimas temperature map’s sharp regional boundaries. The impact that excavated Herschel Crater could have melted surface ice, which created a watery expanse that subsequently became a flash-frozen, hard surface. Nevertheless, Spencer points out the puzzling presence of an intact, dense top layer that already should have been pulverized by meteorites and other space debris.

The takeaway for Herschel Crater’s appearance as a dot eaten by Pac-Man in a Mimas temperature map is that the data gathered Feb. 13, 2010, by the Cassini-Huygens spacecraft’s composite infrared spectrometer (CIRS) created a temperature map that resembles a gameplay of the Pac-Man video game franchise, with Pac-Man’s jaws representing the map’s warmest temperatures and Herschel Crater’s Pac-Dot depicting an oasis of less cold temperatures within the map’s coldest region.

Pac-Man, a maze arcade game developed and released May 22, 1980, in Japan and Oct. 10, 1980, in North America, makes a pareidolic appearance in a Cassini-Huygens spacecraft-generated temperature map of Saturnian moon Mimas: PAC-MAN @pacman, via Facebook Feb. 6, 2009

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Barber, Todd J. “Insider’s Cassini: Dr. John Spencer and Unexpected Mimas Temperature Data.” NASA Science Solar System Exploration > News. March 30, 2010.
Available @ https://solarsystem.nasa.gov/news/11176/

Garner, Robert, ed. “Goddard Instrument Aboard Cassini Spacecraft Sees ‘Pac-Man’ on Saturn Moon.” NASA . Centers > Goddard Space Flight Center > News. March 29, 2010.
Available @ https://www.nasa.gov/centers/goddard/news/features/2010/pac-man-mimas.html

Lavoie, Sue, site manager. “PIA 12867: Bizarre Temperatures on Mimas.” NASA Jet Propulsion Laboratory Photojournal. Image added March 29, 2010.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA12867

Levy, David H. Skywatching. Revised and updated. San Francisco CA: Fog City Press, 1994.

Marriner, Derdriu. “Herschel Crater Vicinity Has Weaker Infrared Brightness Than Mimas Norm.” Earth and Space News. Wednesday, Oct. 26, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/10/herschel-crater-vicinity-has-weaker.html

Marriner, Derdriu. “Mimantean Crater Herschel Displays Subtle Colors in Close Flyby View.” Earth and Space News. Wednesday, Oct. 12, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/10/mimantean-crater-herschel-displays.html

Marriner, Derdriu. “Mimantean Crater Herschel Honors Mimas Discoverer William Herschel.” Earth and Space News. Wednesday, Sept. 7, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/09/mimantean-crater-herschel-honors-mimas.html

Marriner, Derdriu. “Mimantean Crater Herschel Partially Overlies Oeta Chasma.” Earth and Space News. Wednesday, Oct. 5, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/09/mimantean-crater-herschel-partially.html

Marriner, Derdriu. “Mimantean Crater Herschel Reveals Dark Areas in Close Flyby View.” Earth and Space News. Wednesday, Oct. 19, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/10/mimantean-crater-herschel-reveals-dark.html

Marriner, Derdriu. "Mimas Temperature Map Shows Unexpected Coldness Around Herschel Crater." Earth and Space News. Wednesday, Nov. 2, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/10/mimas-temperature-map-shows-unexpected.html

Marriner, Derdriu. “William Herschel Discovered Mimas With Newly Built 40-Foot Telescope.” Earth and Space News. Wednesday, Sep. 21, 2019.
Available @ https://earth-and-space-news.blogspot.com/2011/09/william-herschel-discovered-mimas-with.html

Marriner, Derdriu. “William Herschel Discovered Saturnian Moon Mimas Sept. 17, 1789.” Earth and Space News. Wednesday, Sept. 14, 2011.
Available @ https://earth-and-space-news.blogspot.com/2011/09/william-herschel-discovered-saturnian.html

Moore, Patrick, Sir. Philip’s Atlas of the Universe. Revised edition. London UK: Philip’s, 2005.

PAC-MAN @pacman. “Added a new photo.” Facebook. Feb. 6, 2009.
Available @ https://www.facebook.com/pacman/photos/a.67802275927/67802510927/

U.S. Geological Survey. “Preliminary Pictorial Map of Mimas.” Atlas of the Saturnian Satellites. IMAP 1482. Prepared for the Voyager Imaging Team in cooperation with the Jet Propulsion Laboratory, California Institute of Technology and the National Aeronautics and Space Administration. Directed by R.M. (Raymond Milner) Batson / U.S. Geological Survey Branch of Astrogeologic Studies. Airbrush representation by Jay L. Inge. Data preparation and preliminary image processing by K.F. Mullins, Christopher Isbell, E.M. Lee, H.G. Morgan and B.A. Skiff. Reston VA: U.S. Geological Survey, 1982.
Available @ https://pubs.er.usgs.gov/publication/i1489
Available @ http://171.67.35.48/view/6829740

Whatmore, Rebecca, ed. “Bizarre Temperatures on Mimas.” NASA > Mission Pages > Cassini-Huygens Mission to Saturn > Multimedia. March 29, 2010.
Available @ https://www.nasa.gov/mission_pages/cassini/multimedia/pia12867.html

Saturday, November 5, 2011

Great Blue Heron Habitats: Blue Body, Blue-Green Egg, Platform Nest

Summary: North American great blue heron habitats in coniferous and deciduous wooded wetlands sustain blue bodies, blue-green eggs and platform nests.

Great blue herons (Ardea herodias) build a lofty nest in Florida: Lee Karney/U.S. Fish and Wildlife Service, Public Domain, via USFWS National Digital Library

North American great blue heron habitats alleviate cultivator anxieties over meadow lizard and mouse populations and award naturalists with distribution ranges seasonally in Canada and Mexico and year-round in the United States.

The great blue heron bears its common name and the scientific name Ardea herodias ([Latin] heron [Greek] heron) as one of the world's three largest herons. Agro-industry, aquaculture, development, pesticides, pollution, predation, recreation and tourism challenge great blue herons, described in 1758 by Swedish zoologist Carl Linnaeus (May 23, 1707-Jan. 10, 1787). Freshwater and saltwater wetlands with ledges, mangroves and outcrops draw great blue herons into solitary and flocked life cycles with cormorants, ibises, other herons and pelicans.

Twenty-year lifespans in Canada summers, Mexico winters and the United States year-round expect inaccessible, remote flooded fields, lakes, mangroves, marshes, rivers, swamps and tidal grass flats.

November through August furnish opportunities in nesting and roosting colonies for brooding one two- to seven-egg clutch, preferably at 130 feet (39.62 meters) above the ground.

Fathers-to-be over three to 14 days give mothers-to-be branches and sticks for grass-, leaf-, twig-lined platform nests with 25- to 40-inch (63.5- to 101.6-centimeter) outside diameters. Nests house 1.85- to 2.79-inch (4.7- to 7.1-centimeter) by 1.38- to 1.97-inch (35- to 50-centimeter), oval, elliptical to subelliptical, pale blue-green, smooth or semi-rough, unmarked eggs. Parents-to-be incubate completed clutches for 25 to 30 days unless equipment operation and foot traffic inspire nest abandonment and institute repeat mating and second clutches elsewhere.

Agro-industry, aquaculturists and construction and bears, common and northwest crows, eagles, pollution, raccoons, ravens, red-tailed hawks and turkey vultures jeopardize North American great blue heron habitats.

Semi-helpless nestlings know blunt, short bills, bristle-tipped, long, smoky-gray down on crowns, long down on dark gray-brown upperparts and on pale gray flanks and white undersides.

The first three to four weeks parents lavish round-the-clock care on nestlings who learn to fly at 60 days and leave four to 30 days later. Nestlings mature on regurgitated fish from their parents' flexible, storageable digestive systems and mix physical independence within three, and sexual maturity within 22, months of hatching. Adults need nourishment from bass, crabs, crayfish, dragonflies, flounder, frogs, gophers, grasshoppers, gunnel, lizards, mice, perch, rails, salamanders, sculpin, shrimp, smelt, snakes, stickleback, turtles and voles.

North American great blue heron habitats up through 8,530.18-foot (2,600-meter) altitudes above sea level offer winter-coldest temperatures at minus 45 degrees Fahrenheit (minus 42.78 degrees Celsius).

Great blue herons prefer 2- to 4-mile (3.22- to 6.44-kilometer) distances between forages and nests and roosts in all-coniferous, all-deciduous or mixed forests, groves and woodlands.

Ash, aspen, birch, elm, fir, hemlock, hickory, mangrove, maple, oak, pine, spruce and white cedar qualify as camouflage alongside, in or near water bodies and wetlands. Blue-gray bodies, dark bills, legs and wing-tips, gray S-shaped necks crooked backward in flight and white faces reveal adult males with brown-bodied, dark-tailed females and juveniles. Deep-flapping, regular-beating flight on 5.25- to 6.5-foot (1.6- to 1.98-meter) wingspans suggest 2.75- to 4.25-foot (0.84- to 1.29-meter) long, 4.75- to 5.5-pound (2.15- to 2.49-kilogram) adults.

North American great blue heron habitats tend to transmit no voices other than the barking, loud squawk and crank vocalizations of breeding colonies and disrupted flocks.

illustration of great blue heron (Ardea herodias) eggs; Illustrations of the Nests and Eggs of Birds of Ohio, Plate LIV, figure 7, opposite page 188: Public Domain, via Biodiversity Heritage Library

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Great blue herons (Ardea herodias) build a nest in Florida: Lee Karney/U.S. Fish and Wildlife Service, Public Domain, via USFWS National Digital Library @ https://digitalmedia.fws.gov/cdm/singleitem/collection/natdiglib/id/17740/rec/3

illustration of great blue heron (Ardea herodias) eggs; Illustrations of the Nests and Eggs of Birds of Ohio, Plate LIV, figure 7, opposite page 188: Public Domain, via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/34908331

For further information:

Audubon, John James. "Great White Heron Ardea occidentalis." Ornithological Biography or, An Account of the Habits of the Birds of the United States of America; Accompanied by Descriptions of the Objects Represented in the Work Entitled The Birds of America, and Interspersed with Delineations of American Scenery and Manners, vol. III: 542-552. Edinburgh Scotland: Adam and Charles Black, MDCCCXXXV (1835). Vol. III, p. 542-552 and Vol. V, p. 596.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/33238012

Audubon, John James. 1839. "Great White Heron Ardea occidentalis." Ornithological Biography or, An Account of the Habits of the Birds of the United States of America; Accompanied by Descriptions of the Objects Represented in the Work Entitled The Birds of America, and Interspersed with Delineations of American Scenery and Manners, vol. V: 596-599. Edinburgh Scotland: Adam and Charles Black, MDCCCXXXIX.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/33240594

Baicich, Paul J.; and Harrison, Colin J.O. Nests, Eggs, and Nestlings of North American Birds. Second edition. Princeton NJ: Princeton University Press, Princeton Field Guides, 2005.

Bangs, Outram. "Description of a New Race of the Great Blue Heron From the Galapagos islands: Ardea herodias cognata subsp. nov." Proceedings of the New England Zoölogical Club, vol. III (Feb. 6, 1903), pp. 99-100.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/12603773

Chapman, Frank M. "A New Race of the Great Blue Heron, With Remarks on the Status and Range of Ardea wardi: Ardea herodias fannini, subsp. nov." Bulletin of the American Museum of Natural History, Vol. XIV, Article VIII (April 18, 1901), pp. 87-90.
Available via AMNH Research Library Digital Repository @ http://digitallibrary.amnh.org/bitstream/handle/2246/734//v2/dspace/ingest/pdfSource/bul/B014a08.pdf?sequence=1&isAllowed=y

Grzimek's Animal Life Encyclopedia, 2nd edition. Volumes 8-11, Birds I-IV, edited by Michael Hutchins, Jerome A. Jackson, Walter J. Bock and Donna Olendorf. Farmington Hills MI: Gale Group, 2002.

Jones, Howard. 1886. Illustrations of the Nests and Eggs of Birds of Ohio. Illustrations by Mrs. N.E. Jones. Vol. II. Circleville OH: s.n. (sine nomine).
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/34908243

Linneaus, Carl. 1758. "11. Ardea herodias." Systema Naturæ: 143. Editio Decima, Reformata. Holmiae [Stockholm, Sweden]: Laurentii Salvii [Laurentius Salvius].
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/727050

Peterson, Alan P., M.D. "Ardea herodias Linnaeus 1758." Zoonomen: Zoological Nomenclature Resource > Birds of the World -- Current Valid Scientific Avian Names > Pelecaniformes > Ardeidae > Ardea.
Available @ http://www.zoonomen.net/avtax/pele.html

Ridgway, Robert. "On an Apparently New Heron from Florida." Bulletin of the Nuttall Ornithological Club, vol. VII, no. 1 (January 1882), pp. 1-6.
Available via Biodiversity Heritage Library @ http://biodiversitylibrary.org/page/21225900

Friday, November 4, 2011

Excoecaria Parvifolia Botanical Illustrations: Australia's Gutta-Percha

Summary: Excoecaria parvifolia botanical illustrations, not Palaquium gutta and Betula pubescens images, depict Australia's gutta-percha and northern brown birch.

Gutta-percha tree images and northern brown birch tree images are associated with Excoecaria parvifolia botanical illustrations in Australia and with Palaquium gutta botanical illustrations and Betula pubescens var. pumila botanical illustrations elsewhere.

Australian gutta-perchas (from the Malay getah, "latex" and perca, "cloth-strips") and northern brown birches bear their common names because of rubbery sap and northern distribution ranges. They carry their scientific name Excoecaria parvifolia, from the Latin excaecāre ("to make blind") and same-spelled adjective ("small-leafed"), for temporary sightlessness from contact with their latex. Their Euphorbiaceae (from the Greek physician Εὐφορβος, Eúphorbos, "well-fed") spurge family membership derives from scientific descriptions by Johannes Müller (May 9, 1828-Jan. 28, 1896) in 1864.

Australian gutta-percha trees and northern brown birches exist endemically in clay-soiled, seasonally waterlogged flats and somewhat saline wetlands in the Northern Territory, Queensland and Western Australia.

November through December and January through April fit into Excoecaria parvifolia life cycles as respective flowering and fruiting months for gutta-percha trees and northern brown birches.

Gutta-percha trees and northern brown birches grow from broad-tipped, oblong-oval, smooth, white-brown, 0.19-inch- (5-millimeter-) long seeds that group with spurge family members without, not with, caruncles. Ant-attracting, attached, fleshy caruncles (from the Latin caruncula, "wart") and elaiosomes (from the Greek έλαιον, élaion, "olive oil" and σόμα, sóma, "body") harbor lipids and proteins. Fruiting intervals impress each schizocarp (from the Greek σχίζω, skhízō, "I split" and καρπός, karpós, "fruit") into three one-seeded mericarps (from the Greek μερίς, merís, "part").

Gutta-percha tree images and northern brown birch tree images in Excoecaria parvifolia botanical illustrations juggle lengthwise-opened, two-celled anthers; three base-fused, two-lobed styles; and three-cavitied, three-ovuled ovaries.

Minute outer-whorled perianths (from the Greek περί, perí, "around" and άνθος, ánthos, "flower") keep 0.39-inch- (10-millimeter-) long male flowers and their lone stamens within leaf-like enclosures.

Male flowers look littler than one stalked female flower within every cyathium (from the Greek κυάθιον, kuáthion, "cuplet") of base-fused bracts lodged alternately with nectary glands. Eleven- to 20-year gutta-percha and northern brown birch deciduous (from the Latin dēcīdere, "to fall down" [annually]) life cycles mingle leafing, flowering, fruiting and seeding months. They net black-gray, fissured bark; mature 22.96-foot (7-meter) base-treetop heights; and 0.59- to 1.85-inch- (15- to 47-millimeter-) long, 0.16- to 0.87-inch- (4- to 22-millimeter-) wide leaves.

Leafing gutta-percha tree images and northern brown birch tree images in Excoecaria parvifolia botanical illustrations observe elliptical to lance-oblong or oblong-oval, purple-topped leaves with basal glands.

Boiling inner bark with latex from smooth, succulent foliage on 0.039- to 0.32-inch- (1- to 8-millimeter-) long petioles (from the Latin petiolus, "little foot") provides antiseptics.

Aromatic red wood and sterilized latex qualify guttah-perchas and northern brown birches for respective boomerang and veneer product lines and for natural cut- and wound-cleaning products. Australia's Nature Conservation Act regards gutta-perchas and northern brown birches as of least concern even as mistletoes (Lysiana maritima) parasitically ravage the lagoon- and river-edge resident. Connells Lagoon Conservation Reserve; Elsey, Judbarra/Gregory, Keep River and Limmen National Parks; Giwining/Flora River Nature Park; Limmen Bight Marine Park; and Longreach Waterhole sustain Excoecaria parvifolia.

Noble (Cryptoblepharus exochus) and tawny (Cryptoblepharus ruber) snake-eyed skinks, healthy ecosystem indicators, sometimes tumble over their favorite host plants in Excoecaria parvifolia botanical illustrations and images.

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Australia's gutta-percha (Excoecaria parvifolia) claims sustaining habitats in Elsey National Park, northeastern Northern Territory; Crossing Salt Creek near the Roper River, Eastern Arnhem Land, Australia, July 1911; glass plate negative of eastern Elsey National Park by English-Australian biologist and anthropologist Sir Walter Baldwin Spencer (June 23, 1860-July 14, 1929), Museums Victoria Collections, accession number XP14098, Melbourne, Victoria, southeastern Australia: Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Walter_Baldwin_Spencer_-_Crossing_Salt_Creek_near_the_Roper_River,_Eastern_Arnhem_Land,_Australia,_July_1911_-_Google_Art_Project.jpg; Museum Victoria Collections, Indigenous or Cultural Rights Apply, Copyright expired, via Google Arts Culture @ https://artsandculture.google.com/asset/VwEI6pcQYzePFg; glass plate, All Rights Reserved / Reuse may require cultural clearances, text content, CC BY 4.0 International, via Museums Victoria Collections @ https://collections.museumsvictoria.com.au/items/1765436

Northeastern Northern Territory's Keep River National Park shelters Australia's gutta-percha (Excoecaria parvifolia) as well as striking sandstone formations: Keep River National Park, view from Gurrandalng Walk; Monday, Dec. 1, 1997: Rr2000, CC BY 3.0 Unported, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Keep-River-Nationalpark,_View_from_Gurrandalng.jpg

For further information:

"Excoecaria parvifolia Müll. Arg." Tropicos® > Name Search.
Available @ http://www.tropicos.org/Name/50294780

Horner, Paul. December 2007. "Systematics of the Snake-Eyed Skinks, Cryptoblepharus Wiegmann (Reptilia: Squamata: Scincidae) -- an Australian-Based Review." The Beagle, Records of the Museums and Art Galleries of the Northern Territory Supplement 3: 21-198.
Available via Biodiversity Heritage Library@ https://www.biodiversitylibrary.org/page/55260723#page/25/mode/1up

Müller, J. (Johannes). 3 September 1864. "2. Excaecaria (sect. Euexcaecaria) parvifolia." Flora oder allgemeine botanische Zeitung, herausgegeben von der königl. bayer. botanischen Gesellschaft in Regensburg. Neue Reihe. XXII. Jahrgang. Vol. 47, no. 28: 433-434.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/55899

Wrigley, John; and Murray Fagg. 2007. Australian Native Plants: Cultivation, Use in Landscaping and Propagation. London UK; Sydney, Australia; Auckland NZ: New Holland Publishers.

Wednesday, November 2, 2011

Mimas Temperature Map Shows Unexpected Coldness Around Herschel Crater

Summary: A Mimas temperature map shows unexpected coldness around Herschel Crater, according to data obtained Feb. 13, 2010, by Cassini-Huygens spacecraft.

A Mimas temperature map shows unexpected coldness around Herschel Crater, according to data obtained during the Cassini-Huygens spacecraft’s closest-ever flyby Feb. 13, 2010.

The Saturn-exploring Cassini-Huygens spacecraft made its closest-ever Mimantean flyby on Saturday, Feb. 13, 2010. The spacecraft logged an approximate nearness of 9,500 kilometers (5,900 miles) to Mimas.

On that date, as the spacecraft receded from Saturn’s seventh-known moon, its composite infrared spectrometer (CIRS) gathered data on surface temperatures by way of infrared radiation. The National Aeronautics and Space Administration’s (NASA) Goddard Space Flight Center (GSFC) built and manages the Cassini-Huygens spacecraft’s composite infrared spectrometer. The composite infrared spectrometer is “. . . a major science instrument aboard NASA’s Cassini mission to Saturn,” according to the CIRS team’s website. “It measures the infrared energy from Saturn, its rings and its moons, especially Titan, in order to study their thermal structure and composition,” explains the NASA GSFC CIRS website.

The temperature map, published March 29, 2010, on NASA’s Cassini mission pages, distinguishes a colder part (right) of the Mimantean disk from a warmer part (left). A v-shaped boundary clearly separates the two temperature-differentiated parts.

“The warm part has typical temperatures near 92 Kelvin (minus 294 Fahrenheit), while typical temperatures on the cold part are about 77 Kelvin (minus 320 Fahrenheit),” details the multimedia feature’s author, Rebecca Whatmore.

Greater thermal conductivity of the cold part’s surface materials is suspected as the explanation for the cold part’s coldness. The higher rate of conductivity would allow for transfer of solar energy into subsurface materials as opposed to surface warming effectuated by materials with lower thermal conductivity.

Nevertheless, Whatmore notes: “But why conductivity should vary so dramatically across the surface of Mimas is a mystery.”

The cold part of the spectrometer’s Mimantean temperature map includes Hershel Crater. The huge crater, whose diameter approximates one-third of its parent body’s diameter, exhibits warmer temperatures than its environs.

“It’s not yet known whether Herschel is responsible in some way for the larger region of cold temperatures that surrounds it,” Whatmore adds.

Whatmore’s multimedia feature contrasts the spectrometer’s actual temperature map with a map of the expected temperature distribution on Mimas. A white sun symbol indicates the subsolar point, the point at which the sun is perceived as directly overhead, on the map of expected temperatures. The subsolar point occurs close to the equator at midday.

“Just as on Earth, the highest temperatures (shown in yellow) were expected to occur after midday, in the afternoon,” Whatmore explains.

The actual temperature map, however, presents an unexpectedly different pattern from that of the temperature forecast map. Concentric ovals of smoothly varying temperatures radiate from the moon’s equator, with warmer temperatures encompassing equator-straddling latitudes between the subsolar point and, to its east, Herschel Crater.

The spectrometer required 85 minutes for completion of its actual temperature map of Mimas. Data gathering began at a distance of 38,000 kilometers (24,000 miles) and ended at a distance of 67,000 kilometers (42,000 miles) from Mimas.

During data gathering, Mimantean rotation accounted for an increase of the longitude of the center of the moon’s disk from 128 degrees west to 161 degrees west. The moon’s prominent Herschel Crater claims easternmost and westernmost longitudes of 90.91 degrees west and 131.1 degrees west, respectively, according to the International Astronomical Union’s (IAU) Gazetteer of Planetary Nomenclature. The lunar impact crater registers a northernmost to southernmost latitudinal sprawl of 18.14 degrees north and minus 21.5 degrees south, respectively. Herschel is centered at minus 1.38 degrees south latitude, 111.76 degrees west longitude.

The actual temperature map only approximates “. . . the alignment of the temperatures relative to specific features or coodinates on Mimas . . .” because of the changing geometry that occurred during the map’s creation. “The temperatures were calculated from the brightness of the moon’s infrared heat radiation, measured by CIRS at a wavelength of 12 to 16 microns,” explains Whatmore.

The takeaways for the Mimas temperature map created Feb. 13, 2010, by the Cassini-Huygens spacecraft’s composite infrared spectrometer are that actual temperatures varied unexpectedly from expected temperatures and that an unexpected cold part surrounds the moon’s dominant Herschel Crater.

The Cassini-Huygens spacecraft’s composite infrared spectrometer (CIRS) is a heat-ray detector that covers most of the infrared spectrum; by measuring the strength of different wavelengths of heat rays, the CIRS remotely senses temperatures and distinguishes individual gases via their radiation signatures: courtesy National Aeronautics and Space Administration (NASA), via NASA Cassini at Saturn mission pages

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Upper right image shows unexpected temperature map created from data obtained by the Cassini-Huygens spacecraft’s composite infrared spectrometer (CIRS) on Feb. 13, 2010, the closest-ever flyby of Mimas; lower left image presents Mimas in visible light, with addition of green grid showing latitudes and longitudes at 30-degree intervals; lower right image presents new temperature map on a mosaic of images taken on previous Mimantean flybys; NASA ID PIA12867; image addition date 2010-03-29; image credit NASA / JPL (Jet Propulsion Laboratory) / GSFC (Goddard Space Flight Center) / SwRI (Southwest Research Institute) / SSI (Space Science Institute): May be used for any purpose without prior permission, via NASA JPL Photojournal @ https://photojournal.jpl.nasa.gov/catalog/PIA12867; Generally not subject to copyright in the United States; may use this material for educational or informational purposes, including photo collections, textbooks, public exhibits, computer graphical simulations and Internet Web pages; general permission extends to personal Web pages, via NASA Image and Video Library @ https://images.nasa.gov/details/PIA12867; via NASA Cassini-Huygens mission pages @ https://www.nasa.gov/mission_pages/cassini/multimedia/pia12867.html

Guandique, Ever, cur. “Cassini / CIRS.” NASA GSFC (Goddard Space Flight Center) CIRS (Composite Infrared Spectrometer).
Available @ https://cirs.gsfc.nasa.gov/

Herschel, William. “Account of the Discovery of a Sixth and Seventh Satellite of the Planet Saturn; With Remarks on the Construction of Its Ring, Its Atmosphere, Its Rotation on an Axis, and Its Spheroidical Figure. Read November 12, 1789.” Philosophical Transactions of the Royal Society of London, vol. LXXX, for the Year 1790, Part I: 1-20. London UK: Lockyer Davis and Peter Elmsly, Printers to The Royal Society, MDCCXC (1790).
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/51828893

Herschel, William. “Description of a Forty-Feet Reflecting Telescope. Read June 11, 1795.” Philosophical Transactions of the Royal Society of London for the Year MDCCXCV, vol. LXXXV, Part II: 347-409. London UK: Peter Elmsly, Printer to The Royal Society, 1795.
Available via Biodiversity Heritage Library @ https://biodiversitylibrary.org/page/51831451

International Astronomical Union. “Herschel .” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature. Last updated Aug. 14, 2008.
Available @ https://planetarynames.wr.usgs.gov/Feature/2478

Lavoie, Sue, site manager. “PIA06259: Mimas Showing False Colors #1.” NASA Jet Propulsion Laboratory Photojournal. Image addition date Aug. 5, 2005.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA06257

Lavoie, Sue, site manager. “PIA06259: Mimas Showing False Colors #2.” NASA Jet Propulsion Laboratory Photojournal. Image addition date Aug. 8, 2005.
Available @ https://photojournal.jpl.nasa.gov/catalog/PIA06259

Levy, David H. Skywatching. Revised and updated. San Francisco CA: Fog City Press, 1994.

Moore, Patrick, Sir. Philip’s Atlas of the Universe. Revised edition. London UK: Philip’s, 2005.

Watanabe, Susan, ed. “Mimas Showing False Colors -- 1.” NASA > Mission Pages > Cassini-Huygens Mission to Saturn > Multimedia. Aug. 5, 2005. Page last updated April 29, 2008.
Available @ https://www.nasa.gov/mission_pages/cassini/multimedia/pia06257.html

Watanabe, Susan, ed. “Up Close to Mimas.” NASA > Mission Pages > Cassini-Huygens Mission to Saturn > Multimedia. Aug. 5, 2005. Page last updated April 29, 2008.
Available @ https://www.nasa.gov/mission_pages/cassini/multimedia/pia06258.html