Mercury Flyby 2 |
Mercury Flyby 2 |
Oct 8 2008, 03:58 PM
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#91
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
Here's an updated version of my context map. The new WAC image doesn't quite overlap with the NAC from yesterday, but there is nice overlap with the WAC.
The large crater in the center of the mosaic is Boethius; the large one to the upper right is Polygnotus. --Emily -------------------- My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
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Oct 8 2008, 04:41 PM
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#92
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Senior Member Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 |
In the "are we there yet" spirit, given that this flyby dropped the period of Messenger's orbit from 132 days to 116 days, Flyby #3 (almost a year away) will happen in just a bit more than three orbits. Remembering that the original orbit had exactly a one-year period, we sure have come a long way!
--Greg |
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Oct 8 2008, 04:47 PM
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#93
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Solar System Cartographer Group: Members Posts: 10199 Joined: 5-April 05 From: Canada Member No.: 227 |
Here's a reprojection of the smooth plains image. If this isn't a case of volcanic plains embaying the cratered terrain I'm a monkey's uncle.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Oct 8 2008, 05:01 PM
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#94
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Solar System Cartographer Group: Members Posts: 10199 Joined: 5-April 05 From: Canada Member No.: 227 |
... and another one of the northern limb. This kind of reprojection makes the limb images much easier to interpret.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Oct 8 2008, 05:09 PM
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#95
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
Is it just me or does almost every other "fresher" crater in Doug's combined image here seem to have a scarp bisecting the crater?
-Mike -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Oct 8 2008, 07:28 PM
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#96
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Lord Of The Uranian Rings Group: Members Posts: 798 Joined: 18-July 05 From: Plymouth, UK Member No.: 437 |
Here's a reprojection of the smooth plains image. If this isn't a case of volcanic plains embaying the cratered terrain I'm a monkey's uncle. Wow - are those wrinkle ridges in that picture Phil? If so, does this indicate that this volcanic flow was more viscous than those we typically see on the Moon? -------------------- |
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Oct 8 2008, 08:04 PM
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#97
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The Poet Dude Group: Moderator Posts: 5551 Joined: 15-March 04 From: Kendal, Cumbria, UK Member No.: 60 |
Mercury's starting to look a lot like one of Chesley Bonestell's Moon paintings...
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Oct 8 2008, 10:41 PM
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#98
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Merciless Robot Group: Admin Posts: 8784 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Is it just me or does almost every other "fresher" crater in Doug's combined image here seem to have a scarp bisecting the crater? -Mike I don't think you're wrong. Hmm. Makes you kind of wonder if the crust of Mercury may have extensive deep magma reservoirs above the Hermian equivalent of the Mohorovicic Discontinuity; too deep to produce vulcanism, but enough to cause slumping & shifting after a major impact. -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Oct 9 2008, 04:48 AM
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#99
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Senior Member Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 |
Is it just me or does almost every other "fresher" crater in Doug's combined image here seem to have a scarp bisecting the crater? Well, we haven't actually seen a picture of you, so it's hard to be sure. --Greg :-) |
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Oct 9 2008, 12:43 PM
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#100
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Solar System Cartographer Group: Members Posts: 10199 Joined: 5-April 05 From: Canada Member No.: 227 |
The Vivaldi release - showing that the same crater can be seen in both encounters with opposite lighting - and Juramike's post showing the big southern basin in a composite of two views - suggest that you can combine the views from these two encounters. It's possible but not perfect. Here is one hemisphere:
It works very well. Several craters along the terminator are visible in both views, and the combination of views looks roughly globe-like. The other side doesn't work so well: It's not as symmetric as you might think. But it does give the idea. A proper Steve Albers-style reprojection would allow it to work properly. I'm only playing with Photoshop here. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Oct 9 2008, 03:45 PM
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#101
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Solar System Cartographer Group: Members Posts: 10199 Joined: 5-April 05 From: Canada Member No.: 227 |
And a quick peek at the new image of the rayed crater near the limb, reprojected. Looks like another one with bright material inside it.
Phil (I really should try to get a bit of work done...) -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Oct 9 2008, 04:44 PM
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#102
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Member Group: Members Posts: 813 Joined: 8-February 04 From: Arabia Terra Member No.: 12 |
Just as Mercury has 'hot poles' does it also have, perhaps 'impact poles'; areas which (owing to Mercury's orbital and rotational properties) are likely to receive slightly more and/or slightly higher velocity impacts than other places?
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Oct 9 2008, 04:55 PM
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#103
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Solar System Cartographer Group: Members Posts: 10199 Joined: 5-April 05 From: Canada Member No.: 227 |
No, it doesn't.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Oct 9 2008, 05:00 PM
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#104
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
That question is ringing a bell. Wasn't there a new paper out recently saying that Mercury doesn't have impact poles, but Mars does preferentially have more impacts near the poles?
Today's Key: Inbound: blue squares = NAC approach mosaic Outbound: Yellow = WAC Departure mosaic #1 Blue = NAC Departure mosaic #1 Purple = NAC Departure mosaic #2 Blue-green = NAC Departure mosaic #3 --Emily
Reason for edit: Added the third image release from today to the context map.
-------------------- My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
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Oct 9 2008, 05:03 PM
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#105
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Member Group: Members Posts: 813 Joined: 8-February 04 From: Arabia Terra Member No.: 12 |
No, it doesn't. Phil Why not? It is true that Mercury is not tidally locked, like the moon (which does have cratering asymmetry for that very reason*), but it does have that 3:2 spin-orbit resonance resulting in a notable insolation asymmetry. Maybe I should crunch some numbers and find out. * QUOTE Recent work has re-opened the question of lunar
cratering asymmetries. Examination of the spatial distribution of rayed (and thus likely young) craters gave evidence for a higher density on the Moon's leading hemisphere[5][6], with an amplitude 150% that of the trailing hemisphere. This seems to be in agreement with a simple dynamical estimate [7], given that the Moon orbits the Earth at 1.0 km/sec and thus sweeps up more impactors (capable of generating a crater larger than a given diameter) on its leading than trailing hemisphere. A recent numerical study [8] re- examined the hypothesis of an increased nearside crater production due to gravitational focusing by the Earth. It concluded that on average, the cratering rate is approximately a factor of four greater on the near side than on the far side. Lunar Cratering Asymmetries. J. Gallant and B. Gladman LPSC XXXVI |
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