Dislodged Moore F Boulder Left Glowing Wake From Downward Tumbles

Summary: A dislodged Moore F boulder left a glowing wake from downward tumbles on the bright satellite crater’s northeastern wall.

“Bright boulder trail” captured by Lunar Reconnaissance Orbiter Camera NAC; NASA ID PIA12917; image addition date 2009-10-21; image credit NASA/GSFC/Arizona State University: May be used for any purpose without prior permission, via NASA JPL Photojournal

A dislodged Moore F boulder left a glowing wake from downward tumbles as it journeyed from the bright satellite crater’s northeastern rim and wall.

In frame M110383422R, the Lunar Reconnaissance Orbiter Camera’s (LROC) two Narrow Angle Cameras (NAC) captures an image of a high-albedo trail left by a small boulder during its tumble downward from the northeastern rim of boulder-rich Moore F. Albedo (Latin: “whiteness”) concerns the relative amount of solar radiation reflected by a surface versus the total amount received. High-albedo surfaces, which are highly reflective, appear bright. As low reflectors, low-albedo surfaces are dark.

Arizona State University (ASU) LROC scientist Samuel Lawrence suggests in his Oct. 31, 2009, post on the ASU LROC website that a small meteorite’s impact could have dislodged the boulder from the rim. The boulder’s downward trek loosened high-albedo material in the bright satellite’s wall that created a glowing wake of its tumbles. He placed the boulder’s diameter at 3 meters.

Planetary scientist Jeff Plescia notes Moore F’s striking terraced rim and central uplift in his Oct. 30, 2009, post on the ASU LROC website. LROC NAC frame M110383422LE captures the frozen impact melt flows and debris that cover the floor around the satellite’s central uplift. The enormous energy release from the impact responsible for satellite F accounted for ensuing melts. During the crater’s equilibration, low spots received melt flows, which then cooled.

Plescia notes that the cause of Moore F’s striking curved cracks is unknown. He hypothesizes that changes in floor topography could fracture the surface of the central melt deposit and create a parallel pattern of tension-induced, curved cracks. Plescia also considers that a volume change during the melt’s cooling and solidification could produce the arcuate, or curved, cracks.

In his Nov. 24, 2010, post, Plescia tackles erosional troughs imaged by LROC NAC frame M128075293R. Numerous erosional troughs occur on the bright satellite’s inner eastern wall.

The frame’s freshest, smooth-floored trough measures approximately 810 meters in length and approximately 140 meters in width near its head. A narrowing to approximately 105 meters in the trough’s middle then expands to approximately 200 meters.

Older, lower-albedo troughs are sited to the north and south of the fresh, high-albedo trough. The dark, older troughs and the surrounding terrain exhibit a similar albedo.

The older troughs appear to trace back to the same wall level. Plescia observes that intervals of outcropping bedrock characterize the area of the older troughs’ starting points.

Plescia finds a resemblance between Martian sapping features and the old troughs. Headward trough erosion by groundwater released from the subsurface onto a cliff face is thought to account for Martian sapping features.

Despite the resemblance, Plescia dismisses groundwater as an agent in Moore F’s old troughs. He links the old troughs to flows of dry, fine-grained, unstable debris. Broadening during mobilization yielded a fan-shaped deposit. The distance of the downslope extension from the mouth of the trough measures more than one kilometer.

Moore F numbers as one of two satellites parented by Moore Crater in the lunar far side’s northeastern highlands. Moore F is positioned independently to the east of its parent whereas Moore L is attached to its parent’s south-southeastern outer rim.

In his April 24, 2014, post on the ASU LROC website, Japan Aerospace Exploration Agency’s Hiroyuki Sato notes the reach of Moore F’s fresh (high reflectance) ejecta to approximately 90 kilometers southeast of the satellite. Moore F secondary craters populate the high reflectance area.

The LROC co-investigator suggests that ejecta from Moore F secondary craters may have been responsible for the superb pattern traced by downslope-rushing, ground-hugging ejecta in the highland area’s bumpy topography. Sato explains that the steep walls of the high reflectance area’s craters encourage the ejecta’s downward flows as ground huggers.

The takeaways for dislodged Moore F’s glowing wake are that the small boulder left a bright trail of its descent from Moore F’s northeastern rim, that satellite Moore F’s floor presents a spectacular pattern of parallel curved cracks, that fresh and old erosional troughs occupy Moore F’s inner wall and that ground-hugging flow deposits in a high reflectance area may originate in ejecta from the area’s Moore F’s steep-sloped secondary craters.

“More impact melt!” captured by Lunar Reconnaissance Orbiter Camera NAC; NASA ID PIA12921; image addition date 2009-10-30; image credit NASA/GSFC/Arizona State University: May be used for any purpose without prior permission, via NASA JPL Photojournal

Acknowledgment

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

Image credits:

“Bright boulder trail” captured by Lunar Reconnaissance Orbiter Camera NAC; NASA ID PIA12917; image addition date 2009-10-21; image credit NASA/GSFC/Arizona State University: May be used for any purpose without prior permission, via NASA JPL Photojournal @ https://photojournal.jpl.nasa.gov/catalog/PIA12917

“More impact melt!” captured by Lunar Reconnaissance Orbiter Camera NAC; NASA ID PIA12921; image addition date 2009-10-30; image credit NASA/GSFC/Arizona State University: May be used for any purpose without prior permission, via NASA JPL Photojournal @ https://photojournal.jpl.nasa.gov/catalog/PIA12921

For further information:

Aitken, Robert G. “Joseph Haines Moore: 1878-1949 A Tribute.” Publications of the Astronomical Society of the Pacific, vol. 61, no. 360 (June 1949): 125-128.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://adsabs.harvard.edu/abs/1949PASP...61..125A

Aitken, R. (Robert) G.; C.D. Shane; R.J. Trumpler; and W.H. Wright. “Joseph Haines Moore 1878-1949).” Popular Astronomy, vol. LVII, no. 8, whole no. 588 (October 1949): 372-375.
Available via Harvard ADSABS (NASA Astrophysics Data System Abstracts) @ http://adsabs.harvard.edu/abs/1949PA.....57..372.

Consolmagno, Guy; and Dan M. Davis. Turn Left at Orion. Fourth edition. Cambridge UK; New York NY: Cambridge University Press, 2011.

International Astronomical Union. “Moore.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature. Last updated Oct. 18, 2010.
Available @ https://planetarynames.wr.usgs.gov/Feature/4026

International Astronomical Union. “Moore F.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature. Last updated Oct. 18, 2010.
Available @ https://planetarynames.wr.usgs.gov/Feature/11472

International Astronomical Union. “Moore L.” USGS Astrogeology Science Center > Gazetteer of Planetary Nomenclature. Last updated Oct. 18, 2010.
Available @ https://planetarynames.wr.usgs.gov/Feature/11473

Lawrence, Samuel. “Bright Boulder Trail.” NASA/GSFC (Goddard Space Flight Center)/LROC (Lunar Reconnaissance Orbiter Camera), Arizona State University School of Earth and Space Exploration (SESE). Oct. 21, 2009.
Available @ https://www.lroc.asu.edu/posts/79

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

Marriner, Derdriu. “Far Side Lunar Crater Moore Honors American Astronomer Joseph Moore.” Earth and Space News. Wednesday, Sept. 3, 2014.
Available @ https://earth-and-space-news.blogspot.com/2014/09/far-side-lunar-crater-moore-honors.html

Meyer, H. (Heather). “Breaking Down Walls.” NASA/GSFC (Goddard Space Flight Center)/LROC (Lunar Reconnaissance Orbiter Camera), Arizona State University School of Earth and Space Exploration (SESE). June 24, 2014.
Available @ http://lroc.sese.asu.edu/posts/785

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

NASA Lunar Reconnaissance Orbiter Mission. “Erosional Trough on Crater Wall.” National Aeronautics and Space Administration (NASA) > Missions > Lunar Reconnaissance Orbiter LRO). Nov. 24, 2010.
Available @ https://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lroc-20101124-erosional.html

NASA Lunar Reconnaissance Orbiter Mission. “More Impact Melt!” National Aeronautics and Space Administration (NASA) > Missions > Lunar Reconnaissance Orbiter LRO). Oct. 29, 2009.
Available @ https://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lroc_20091029_moore.html

NASA Science Earth’s Moon. “Moore F. Crater.” NASA Science Earth’s Moon > Resources.
Available @ https://moon.nasa.gov/resources/349/moore-f-crater/

Plescia, Jeff. “Erosional Trough on Crater Wall.” NASA/GSFC (Goddard Space Flight Center)/LROC (Lunar Reconnaissance Orbiter Camera), Arizona State University School of Earth and Space Exploration (SESE). Nov. 24, 2010.
Available @ http://lroc.sese.asu.edu/posts/268

Plescia, Jeff. “More Impact Melt!” NASA/GSFC (Goddard Space Flight Center)/LROC (Lunar Reconnaissance Orbiter Camera), Arizona State University School of Earth and Space Exploration (SESE). Oct. 30, 2009.
Available @ http://lroc.sese.asu.edu/posts/71

Sato, Hiroyuki. “Angular Ejecta Edge.” NASA/GSFC (Goddard Space Flight Center)/LROC (Lunar Reconnaissance Orbiter Camera), Arizona State University School of Earth and Space Exploration (SESE). April 24, 2014.
Available @ http://lroc.sese.asu.edu/posts/150