779:
31:
142:
230:
246:) following the impact, after the soft material underlying the lithosphere flows towards the center to fill the cavity excavated by the impact. The absolute age of the Valhalla structure is not known; however, it is the youngest such feature among the five known multi-ring structures on Callisto. Estimates of its age vary from 2 to 4 billion years.
177:), which like the inner troughs appear to be graben. Although these grabens are wider (up to 30 km) than those in the inner trough zone, they are severely degraded, and are made of a series of small knobs, much like their inner counterparts. There are no indications of volcanic flows or other signs of
237:
The
Valhalla multi-ring structure (like other Callistan multi-ring basins) probably resulted from a giant impact, which punctured the outer ridged lithosphere of the moon and entered the underlying layer consisting of a much softer material. The latter can be warm ice or even a liquid ocean, the
133:
Valhalla is the largest multi-ring basin on
Callisto and in the Solar System (with diameter up to 3,800 km). It was discovered by the Voyager probes in 1979–80 and is located on the leading hemisphere of Callisto, in its Jupiter facing quadrant slightly to the north of the equator (at
257:
to
Valhalla. Such disrupted terrain normally forms as a result of focusing of the seismic energy at the opposite point after the impact. The absence of such disruption supports the presence of a subsurface ocean, which would have absorbed much of the seismic energy, at the time of Valhalla's
166:, when studied at a high resolution, turned out to be discontinuous consisting of a series of small bright knobs surrounded by the smooth dark material. They are obviously very degraded structures. The troughs that are situated further from the center than ridges are sinuous and appear to be
217:). To the south of Valhalla there are Sarakka and Nar impact craters; to the east of it (at the boundary between the inner and outer trough zones) are Sculd crater and Svol Catena. To the west of Valhalla another large multi-ring basin—
124:
are superimposed on
Valhalla. The multi-ring system may have formed as semi-liquid or liquid material underlying the brittle lithosphere punctured by the impactor slumped towards the center of the crater following the impact.
153:: a high albedo circular feature of impact origin. The surface in the central zone is relatively smooth and has a mottled appearance. Many impact craters inside it have dark halos. At the high resolution achieved in some
119:
Valhalla consists of a bright central region 360 km across, an inner ridge and trough zone, and striking concentric rings extending up to about 1,900 km from the center. Several large impact craters and
221:—can be found. The central parts of Valhalla are less cratered than the old plain outside the structure. This indicates that Valhalla is significantly younger than Callisto itself.
159:
images the central part of
Valhalla looks like a knobby terrain, where bright knobs are surrounded by dark smooth plains; there is noticeable deficit of small impact craters.
281:(2009) contains a detailed description of a large city built around the concentric rings of Valhalla in the 29th century. The same city is briefly mentioned in Robinson's
213:
can be found as well as Egdir and Mimir craters. The catena consists of a linear sequence of impact craters and probably resulted from a break-up of a comet (like comet
162:
The inner ridge and trough zone surrounds the central palimpsest. The ridges that immediately surround the central zone have steep flanks facing outward. These
962:
173:
The outer trough zone has a radius of 1500 to 1900 km. Its outer boundary is not well defined. It consists of wide double walled sinuous lineaments (
967:
606:
519:
636:
302:
88:
150:
138:
point of view
Valhalla consists of three zones: the central zone, the inner ridge-and-trough zone, and the outer trough zone.
901:
921:
599:
267:
709:
641:
850:
896:
337:
592:
145:
The central part of
Valhalla structure on Callisto. Bright knobs surrounded by smooth dark plains are visible.
472:
377:
Greeley, R.; Klemaszewski, J.E.; Wagner L.; et al. (2000). "Galileo views of the geology of
Callisto".
342:
568:
242:
data. The formation of a ringed structure is caused by the concentric failure of the brittle outer shell (
778:
550:
310: – Roughly circular ring or plateau, possibly discontinuous, surrounding an impact crater's center
170:(about 20 km wide). The inner trough zone extends up to 950 km from the center of Valhalla.
829:
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500:
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Moore, Jeffrey M.; Chapman, Clark R.; Bierhaus, Edward B.; et al. (2004).
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574:. In Bagenal, Fran; Dowling, Timothy E.; McKinnon, William B. (eds.).
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209:
are located within
Valhalla structure. At the northern margin of it
253:
spacecraft found no evidence of disruption of the area of
Callisto
714:
228:
149:
The inner zone (diameter of about 360 km) is an example of a
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189:
images. So, all structures within Valhalla basin have impact or
588:
584:
181:
activity associated with the graben on the high resolution
80:
74:
62:
27:
Large multi-ring impact crater on Jupiter's moon Callisto
312:
Pages displaying short descriptions of redirect targets
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185:
images as was suggested based on the low resolution
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65:
59:
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793:
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650:
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520:"Oceans in the icy Galilean satellites of Jupiter?"
112:, the hall where warriors are taken after death in
71:
68:
415:Shenk, Paul M. (1995). "The geology of Callisto".
330:
134:about 18°N latitude and 57°W longitude). From the
576:Jupiter: The planet, Satellites and Magnetosphere
474:Controlled Photomosaic Map of Callisto JC 15M CMN
490:"Geological Evidence for an Ocean on Callisto"
477:(Map) (2002 ed.). U.S. Geological Survey.
372:
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600:
249:Consistent with this picture, imaging by the
8:
410:
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790:
626:
607:
593:
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233:The troughs (faults) surrounding Valhalla
488:Klemaszewski, J.A.; Greeley, R. (2001).
451:"Callisto, one of Jupiter's moons, 1979"
238:existence of which can be inferred from
34:Valhalla multiring structure on Callisto
29:
637:List of geological features on Callisto
322:
303:List of geological features on Callisto
497:Lunar and Planetary Science Conference
7:
351:participating institution membership
963:Surface features of Callisto (moon)
25:
968:Impact craters on Callisto (moon)
777:
518:Spohn, T.; Schubert, G. (2003).
55:
417:Journal of Geophysical Research
902:Jupiter Magnetospheric Orbiter
1:
578:. Cambridge University Press.
547:10.1016/S0019-1035(02)00048-9
399:10.1016/S0032-0633(00)00050-7
744:
739:
642:List of craters on Callisto
379:Planetary and Space Science
984:
851:Jupiter Icy Moons Explorer
299: – Crater on Callisto
268:Jupiter's moons in fiction
265:
897:Jupiter Icy Moons Orbiter
775:
338:Oxford English Dictionary
453:. Science & Society
391:2000P&SS...48..829G
343:Oxford University Press
234:
146:
35:
232:
144:
33:
273:Kim Stanley Robinson
108:. It is named after
922:Callisto in fiction
539:2003Icar..161..456S
505:2001LPI....32.1818K
429:1995JGR...10019023S
341:(Online ed.).
129:General description
423:(E9): 19, 023–40.
308:Peak ring (crater)
235:
201:Several prominent
147:
36:
950:
949:
910:
909:
773:
772:
437:10.1029/95JE01855
349:(Subscription or
97:) is the largest
16:(Redirected from
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942:Moons of Jupiter
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549:. Archived from
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297:Adlinda (crater)
215:Shoemaker-Levy 9
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278:Galileo's Dream
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114:Norse mythology
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927:Galilean moons
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869:Europa Clipper
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556:on 2008-02-27.
533:(2): 456–467.
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442:
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385:(9): 829–853.
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321:
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266:Main article:
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203:impact craters
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26:
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18:Mimir (crater)
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122:crater chains
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102:impact crater
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937:Colonization
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844:New Horizons
842:
835:
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765:Gomul Catena
734:
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551:the original
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455:. Retrieved
445:
420:
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211:Gomul Catena
200:
182:
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148:
132:
118:
106:Solar System
50:
37:
787:Exploration
457:February 5,
258:formation.
244:lithosphere
38:Located on
957:Categories
809:Pioneer 11
802:Pioneer 10
688:Omolʹ
569:"Callisto"
353:required.)
332:"Valhalla"
318:References
262:In fiction
151:palimpsest
136:geological
99:multi-ring
890:Cancelled
878:Tianwen-4
823:Voyager 2
816:Voyager 1
693:Tornarsuk
255:antipodal
179:endogenic
735:Valhalla
710:Heimdall
616:Callisto
499:: 1818.
291:See also
193:origin.
191:tectonic
110:Valhalla
51:Valhalla
47:Callisto
830:Galileo
757:Catenae
658:Adlinda
651:Craters
623:Geology
535:Bibcode
501:Bibcode
425:Bibcode
387:Bibcode
251:Galileo
207:catenae
197:Craters
187:Voyager
183:Galileo
175:troughs
156:Galileo
104:in the
40:Jupiter
881:(2029)
873:(2024)
861:Future
720:Keelut
698:Utgard
668:Asgard
527:Icarus
225:Origin
219:Asgard
168:graben
164:scarps
915:Other
745:Mimir
740:Egdir
730:Tindr
715:Jalkr
683:Njord
663:Arcas
630:Lists
572:(PDF)
554:(PDF)
523:(PDF)
493:(PDF)
347:
932:Life
794:Past
725:Lofn
673:Burr
459:2009
284:2312
205:and
90:val-
44:moon
705:Hár
678:Doh
543:doi
531:161
433:doi
421:100
395:doi
275:'s
92:HAL
42:'s
959::
541:.
529:.
525:.
495:.
431:.
419:.
407:^
393:.
383:48
381:.
359:^
335:.
287:.
116:.
94:-ə
49:,
608:e
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397::
389::
345:.
84:/
81:ə
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75:æ
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53:(
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