| Piú viste - The Moon from JAXA - The "Kaguya" Lunar Probe |
Kaguya-038-Pico_Mons-tc_017_l-LXTT.jpgPico Mons (Absolute Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)379 visiteMons Pico is a solitary Lunar Mountain that lies in the Northern part of the Mare Imbrium Basin, and to the South of the Dark-Floored Crater Plato.
Pico's peak forms part of the surviving Inner Ring of the Imbrium Basin. This Ring continues to the North-West, with the Montes Teneriffe and Montes Recti ranges. This mountain feature was most likely named by Schröter for the Pico von Teneriffe.
The Selenographic Coordinates of this Peak are 45,7° North Lat. and 8,9° West Longitude. It forms an elongated feature with a length of about 25 Km (oriented N/W-S/E) and a width of approx. 15 Km. The Peak rises to a height of only 2,4 Km, comparable to the maximum altitude of the Montes Teneriffe.
Due to its isolated location on the Lunar Mare Imbrium, however, this Peak can form prominent shadows when illuminated by oblique sunlight. Also, a smaller Peak to the South of Mons Pico (designated "Pico B") can be found. This Region of the Mare Imbrium is also notable for a number of Wrinkle Ridges.MareKromium
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Kaguya-037-Marius_Hill-tc_039.jpgMarius' Hills Region: possible Skylight283 visiteCaption JAXA:"Images of a possible 65 mt diameter Lunar Lava Tube Skylight in the Marius Hills District taken by SELENE Terrain Camera (TC) and Multi-band Imager (MI).
(Upper left frame) Overview of the Region (TC, 20 May 2008; 12,9 to 14,4° North Latitude and 55,7 to 57° West Longitude - approx. 35 x 45 Km.
(Upper right frame) The Skylight (a.k.a.: the "Marius Hills' Hole"; MHH) at 303,3° East and 14,2° North, in a Rille ("Rille A").
(Lower four frames) Enlarged TC and MI images of MHH (1st and 2nd frame from the left are TC images from 20 May 2008 and 21 January 2009; 3rd and 4th are MI images from 17 March 2009 and 13 April 2009).
Arrows indicate the directions of Solar Illumination (I) and the view vector from the camera (V).
The depth of MHH has been estimated to be 80 to 88 meters. If there exists a Lava Tube under MHH, its maximum width can be wider than a few hundred meters".MareKromium
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Kaguya-036-Mare_Orientale-mi_006_2_l.jpgMare Orientale275 visitenessun commentoMareKromium
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Kaguya-035-Lunar_Terrain-tc_035_1_l.jpgFrom Light to Darkness: Lunar Terrain250 visiteCaption JAXA:"This image was obtained using TC cameras of the Kaguya Probe about 10 minutes prior to the KAGUYA's controlled impact on the Moon. Observation location was between Craters Drygalski and Ashbrook (approx. 83° South and 260° East); the probe's altitude was about 18.500 meters".MareKromium
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Kaguya-038-_Rupes_Recta.jpgRupes Recta211 visitenessun commentoMareKromium
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Kaguya-034-Haruyama2009Fig2_edm.jpgWindow onto an abyss: Cave Skylight on the Moon! (EDM)110 visitenessun commentoMareKromium
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001-Kaguya-20071009_kaguya_02l.jpgRstar Separation from Kaguya (1) - before separation101 visiteKAGUYA consists of the Main Orbiter and two small satellites (Relay Satellite and VRAD Satellite). The Main Orbiter will reach the vicinity of the Moon. Once it has reached the Moon, it will be placed into a peripolar orbit at an altitude of 100 Km. The Relay Satellite will be placed in an elliptic orbit at an apogee of 2400 Km, and will relay communications between the Main Orbiter and the ground station.
The VRAD Satellite will play a significant role in measuring the gravitational field around the Moon.
The Main Orbiter will be employed for about one year and will observe the entire Moon.
(in this picture: on the left is the Rstar, and on the right is the VRAD Satellite).MareKromium
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Kaguya-000-20071107.jpgThe North Pole of the Moon85 visiteCaption JAXA:"This is a still image taken out from the first moving image shooting when the KAGUYA Probe flew from the Northern Area of the Oceanus Procellarum (*1) to the center of the North Pole.
As the altitude near the North Pole is high, the angle of the coming sunlight was lower, thus the shade of the crater topography looks long in the image.
The moving image was taken at 04:07 a.m. on October 31st, 2007 (JST) by eight-fold speed intermittent shooting (eight minutes is converged to one minute) from the KAGUYA, and the data was received at the JAXA Usuda Deep Space Center on the same day.
(*1) Oceanus Procellarum:
The dark area on the Moon's surface called "ocean". It is located at the left end of the Northern Hemisphere on the front side of the Moon when we look up at it from the Earth. MareKromium
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Kaguya-033-Haruyama2009Fig1_context.jpgWindow onto an abyss: Cave Skylight on the Moon! (CTX Frame)85 visiteSu segnalazione della nostra sempre attentissima Amica e Partner, Elisabetta Bonora (alias "2di7"), la recente possibile scoperta di un Collapse Pit situato sulla nostra Luna, nella Regione dell'Oceano delle Tempeste (Oceanus Procellarum) ed in prossimità del complesso collinare noto come "Marius Hills".
Eccovi l'interessante articolo scritto al riguardo da Emily Lakdawalla (Planetary Society):"This just in: researchers on JAXA's Kaguya Lunar Orbiter have discovered an open pit on the Moon that is likely a window onto a sublunar world -- a skylight into a subsurface cavern.
Junichi Haruyama, Kazuyuki Hioki, Motomaro Shirao, Tomokatsu Morota, Harald Hiesinger, Carolyn van der Bogert, Hideaki Miyamoto, Akira Iwasaki, Yasuhiro Yokots, Makiko Ohtake, Tsuneo Matsunaga, Seiichi Hara, Shunsuke Nakanotani, and Carlé Pieters describe the feature in a paper now in press in Geophysical Research Letters: "Possible lunar lava tube skylight observed by SELENE cameras.
"First, some context. The Moon will be a difficult, but not impossible, place to set up a permanent human outpost. Lacking a protective atmosphere, its surface is bathed in punishing solar radiation, not to mention a continuous rain of micrometeorites; and over the course of a lunar day (that is, about a month) its temperature ranges over more than 200 degrees Celsius (more than 450 degrees Fahrenheit). Many workers imagining future human habitation of the Moon have advanced the idea of setting up the colony inside a shelter that would provide some protection from the hazards of space radiation and the challenge of insulating against such extremes of temperature.
Digging such a shelter would be a major engineering project; we could get a head start on things if we could find a natural cave. The Moon doesn't have Earth-type limestone rocks bathed in acidic subsurface water, but there is another type of environment that might produce underground caverns: hollow lava tubes. The Moon once had active volcanic geology that has left its surface carved by numerous "sinuous rilles", some of which may once have been underground lava tubes like the ones that form on the flanks of Kilauea today. But while there are lots of rilles to be seen on the Moon, no one has ever confirmed the presence of an enclosed tube, with an intact roof, that could be used as a shelter. One study did find several possible locations where there were likely intact tubes present next to collapsed tube sections (link takes you to a 1.4 MB PDF of a paper by Cassandra Coombs and Ray Hawke), but could not confirm the presence of intact tubes. There are probably lots of intact tubes, but how to find where they're hidden?
The answer is to look for skylights, black holes in the lunar surface that are openings onto sublunar caverns. Skylights are common on Earth, and they've even been seen on the flanks of Martian volcanoes. But despite decades of searching, no one has ever discovered a lunar skylight.
Until now. Haruyama and his coauthors examined Kaguya Terrain Camera photos of an area on the Moon that is populated by numerous rilles, the volcanic complex of the Marius Hills on the lunar nearside. And their search was rewarded with the discovery of exactly one black hole too deep to be an impact crater. The hole is located at 303.3°E and 14.2°N and is, suggetively, in the middle of a small rille. It is nearly circular, 65 meters in diameter, and is equidistant from the rille walls, 250 meters on either side. Previous missions did not image it at high enough resolution to allow scientists to distinguish it from a small impact crater.
Kaguya imaged it nine times, five with the Terrain Camera and four with the lower-resolution Multi-band Imager, at a wide variety of solar incidence angles and camera look angles. A little trigonometry allowed Haruyama et al. to determine that the hole is 80 to 88 meters deep, with very steep walls. The fact that it's deeper than it is wide means it's definitely not an impact crater. But is it a cave skylight? Its location in the dead center of a rille is suggestive, but volcanic environments have a couple of other ways to make pits, such as volcanic vents. But Haruyama et al. determined that a skylight into an underground lava tube is the most likely explanation for this feature; moreover, they figured out that the cavern should be at least 370 meters wide. That's quite a lot of space to work with!
The team searched for more skylights in the region, but only found this one, and as far as they know, it's the only one anybody has ever spotted on the Moon. They concluded: "This is a potentially important discovery for both studies of lunar volcanology and future human outposts....the Marius Hills region has long been considered an important and accessible exploration target, both scientifically and technically. Indeed, the discovery of the Marius Hills Hole further supports the importance of the Marius Hills region as a future exploration target."
This hole is probably not the place we'd establish a permanent base. I imagine that a place that requires a vertical descent and ascent wouldn't be optimal. You'd probably really want one that you could drive into -- an intact tube next to a collapsed part, like the possible ones identified by Coombs and Hawke, and probably ideally with a North or South-facing opening so it wouldn't get blasted by Sunlight at either end of the Lunar Day. I'm smiling now, because I'm thinking about how far humans have come as a species: we're beginning to expand into space, but we're still doing what our forebears did hundreds of thousands (or more) years ago, looking for a nice cave to establish our hearth in.
I want to thank Carolyn van der Bogert for providing the Kaguya images from this paper. Carolyn is also on the Lunar Reconnaissance Orbiter Camera (LROC) team, and told me that LROC has this site on its list of things yet to photograph on the Moon. She said they'll try to photograph it, as Kaguya did, at a variety of solar incidence angles, to get good looks at both the walls of the pit and the floor it opens onto.
LROC should improve on the resolution of the Kaguya imaging by a factor of more than ten, so I'm looking forward to those photos!MareKromium
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Kaguya-005-20071107.jpgThe Western Side of the Oceanus Procellarum84 visiteCaption JAXA:"This is a still image taken out from the end part of the second moving image taking.
We can observe a crater called "Repsold," whose diameter is (about) 107 Km, at the center on the near side of this image. The channel that crosses this crater is called the "Repsold Valley", and its length is about 180 Km (equivalent to the distance between Tokyo and Shizuoka, on the Tokaido Line in Japan). The shooting time was 05:51, on October 31st, 2007.MareKromium
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004-Kaguya-20071009_kaguya_06l.jpgKaguya is approaching the Moon (2)84 visiteCaption JAXA:"Almost the same area as in the previous image, but closer to the Moon".
(This image was taken around 15:00 on Oct. 5th (JST) at a distance of about 1.200 Km from the Moon)MareKromium
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005-Kaguya-20071009_kaguya_07l.jpgKaguya is approaching the Moon (3)81 visiteCaption JAXA:"A boundary in the lower left is the line between the area that receives sunshine and the shaded area at around 80° North Latitude.
It was too dark to observe the North Pole".
(This image was taken around 15:10 on Oct. 5th (JST) at a distance of about 800 Km from the Moon)"MareKromium
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