IPB

Welcome Guest ( Log In | Register )

32 Pages V  « < 29 30 31 32 >  
Reply to this topicStart new topic
LROC news and images
James Fincannon
post May 8 2012, 02:20 PM
Post #451


Junior Member
**

Group: Members
Posts: 55
Joined: 30-July 09
Member No.: 4887



QUOTE (Phil Stooke @ May 8 2012, 03:03 PM) *
But I would take issue with you on one point. At Apollo 15 you say there is no clear evidence of a flag shadow, and that is true in the first frames, but not in the last three where a very dark shadow appears and moves as expected. Maybe the orientation of the flag is such that the early frames are casting a very thin shadow (i.e. the sun is in the plane of the flag in the mid-morning).


Thanks, Phil.

Yes, I, of course, noticed those frames too during my work on this. My original assessment was that more work was needed (since it was not so clear cut as the three I was sure about) and I couldn't understand the shadows being shown without more modeling/analysis. Eric Jones and I went back and forth about this a lot. If someone in the audience wants to offer a model (i.e. 3D) for the shadow casting for these frames, then we would welcome it. It is baffling. You idea might work but I have not had the time to test it and other theories.
Go to the top of the page
 
+Quote Post
charborob
post May 22 2012, 09:48 PM
Post #452


Member
***

Group: Members
Posts: 589
Joined: 21-September 07
From: Québec, Canada
Member No.: 3908



Spectacular oblique view of Tycho crater has been posted here. Must see!
Go to the top of the page
 
+Quote Post
jasedm
post May 23 2012, 05:27 PM
Post #453


Member
***

Group: Members
Posts: 586
Joined: 22-January 06
Member No.: 655



Beautiful desolation!
Go to the top of the page
 
+Quote Post
Phil Stooke
post Nov 5 2013, 01:54 AM
Post #454


Martian Cartographer
****

Group: Members
Posts: 6982
Joined: 5-April 05
From: Canada
Member No.: 227



New goodies keep turning up on the Moon. Another quasi-Ina structure in Mare Tranquillitatis.

Phil

Attached Image


--------------------
... because the Solar System ain't gonna map itself.
Go to the top of the page
 
+Quote Post
Astro0
post Nov 5 2013, 05:31 AM
Post #455


Senior Member
****

Group: Admin
Posts: 3108
Joined: 21-December 05
From: Canberra, Australia
Member No.: 615



Aww, what a cutie smile.gif

Attached Image
Go to the top of the page
 
+Quote Post
JohnVV
post Nov 6 2013, 06:05 AM
Post #456


Member
***

Group: Members
Posts: 814
Joined: 18-November 08
Member No.: 4489



a quick single image SFS HeightMap of that image

Go to the top of the page
 
+Quote Post
charborob
post Nov 19 2013, 06:19 PM
Post #457


Member
***

Group: Members
Posts: 589
Joined: 21-September 07
From: Québec, Canada
Member No.: 3908



Today's LROC featured image is a spectacular oblique view of Tsiolkovsky's central peak.
Go to the top of the page
 
+Quote Post
mcaplinger
post Dec 18 2015, 03:53 PM
Post #458


Senior Member
****

Group: Members
Posts: 1543
Joined: 13-September 05
Member No.: 497



Earthrise from LRO: http://lroc.sese.asu.edu/posts/895


--------------------
Disclaimer: This post is based on public information only. Any opinions are my own.
Go to the top of the page
 
+Quote Post
Explorer1
post Dec 18 2015, 07:46 PM
Post #459


Senior Member
****

Group: Members
Posts: 1369
Joined: 13-February 10
From: British Columbia
Member No.: 5221



Goodness! That is probably one of the top images of the year right there.
The DSCOVR view at the time seems almost tame by comparison....
http://epic.gsfc.nasa.gov/epic-archive/png...12120347_00.png
Go to the top of the page
 
+Quote Post
Tom Dahl
post Dec 18 2015, 11:40 PM
Post #460


Junior Member
**

Group: Members
Posts: 57
Joined: 3-May 12
From: Massachusetts, USA
Member No.: 6392



Wow! That Earthrise image is incredible. Thank you for posting the link to it.
Go to the top of the page
 
+Quote Post
Phil Stooke
post Feb 22 2017, 05:10 PM
Post #461


Martian Cartographer
****

Group: Members
Posts: 6982
Joined: 5-April 05
From: Canada
Member No.: 227



I'm replying here to James Ficannon's post in the Apollo from LRO thread. He linked to an image of a very unusual object in images of the floor of Paracelsus C on the far side.

------------------
James:

By the way, any opinion of this blocky thing in Paracelsus C others have found? Simplified link to QuickMap.

http://bit.ly/2ljHDYT

Maybe it is just a blocky thing, but I would like it if there were a lot more blocky things in the area which there are not.
--------------------

Me:
That has to be one of the most puzzling things I have ever seen on the Moon. I looked at it with morning and afternoon illumination, and with the Sun nearly overhead. The shadows on the southern object hardly seem to make sense at all, and the northern one is not much better. No idea what it is. Some 3D modelling from stereo images would be useful... I see some of that has been done already, but I am not sure the shadows work with the suggested shape. I will keep thinking about it.

Phil
--------------------


Now I have had some time to think about it. I have a geometric interpretation of the southern object which makes sense to me:

Attached Image


(I'm still thinking about the northern object, but ultimately I expect it to be similar).

So, I interpret this thing as a steeply oriented thin rock slab. Just using the Quickmap scale bar, it seems to be about 50 m long, maybe 20 m high and maybe 4 m thick with an irregular top edge. There is a linear depression next to the object on it south side, probably a sign of a buried chunk of the same type of material. The shadows make sense to me now.

What can it be? It is on a small mound, one of several on the south floor of Paracelsus C at the foot of the southern wall. I would interpret it as a slab of impact melt (we see flows of melt around many other craters), originally on the rim of the crater and probably long buried under ejecta from other craters to protect it for a billion years or so. Then a wall slump brings it to the floor of Paracelsus C. The slump is the source of the mounds on the floor, and was probably caused by shaking associated with a big impact. By chance these long-buried but coherent, massive slabs of melt end up sticking out of the ground. This whiole area has a 'hilly and lineated' appearance resembling similar terrain on Mercury which has been interpreted as caused by seismic shaking from a giant antipodal impact (Imbrium).

A bit ad hoc, but not as ad hoc as an entrance to an alien base. I would also be happier if there were other similar objects nearby. But you can't have everything.

Phil


--------------------
... because the Solar System ain't gonna map itself.
Go to the top of the page
 
+Quote Post
Gerald
post Feb 22 2017, 06:32 PM
Post #462


Senior Member
****

Group: Members
Posts: 1736
Joined: 7-December 12
Member No.: 6780



By "crater counting", these slabs seem to be as old as the surrounding surface, covered with small old craters. Old, since the small craters themselves look usharp due to microcratering.
A few hundred meters east of the slabs, some larger craters seem to be considerably(?) younger.
About one km west of the slabs there is an old large impact crater with ejecta (a hill) to the east, hence likely caused by an impactor coming from a western direction.
The slabs might be part of these ejecta.
Right of the slabs, there are traces of a sector of a disk with a radius of about 200m, and with the slabs near the center of the disk.
The slabs might have fallen back earlier than some of finer material and shadowed it causing the subtle structure.
Before the impact, the slabs might have been part of a basalt layer under the surface regolith, just shallow enough to be partially broken up by the impact.

...one of many conceivable scenarios...
Go to the top of the page
 
+Quote Post
James Fincannon
post Yesterday, 04:29 PM
Post #463


Junior Member
**

Group: Members
Posts: 55
Joined: 30-July 09
Member No.: 4887



Thanks for your suggestions!

I am no lunar scientist but I would have preferred an explanation of either:

1) a boulder that rolled to that spot (since it is at the base of the crater slope) and dust accumulated enough (!!) to cover the tracks or

2) low speed ejecta from elsewhere that landed the block (which broke upon impact) and somehow did not create a crater (like Gerald's suggestion except I cannot see the 1 km west impact that
he says might have caused it, I was expecting something much farther away).

Also, I would like to see examples of similar occurrences elsewhere on the Moon.

I do see a number of spots with very entertaining slabs at the bottom of the crater. For instance, here are a lot of slabs in Giordano Bruno.
http://bit.ly/2mgWnWH
Go to the top of the page
 
+Quote Post
Gerald
post Yesterday, 04:46 PM
Post #464


Senior Member
****

Group: Members
Posts: 1736
Joined: 7-December 12
Member No.: 6780



Re 2) Do you see the fuzzy shadow of almost 500m diameter 1km to the left from the slabs? I'd interprete this as an old impact crater. Over time, the craters erode due to subsequent impacts.
Go to the top of the page
 
+Quote Post
James Fincannon
post Yesterday, 05:03 PM
Post #465


Junior Member
**

Group: Members
Posts: 55
Joined: 30-July 09
Member No.: 4887



QUOTE (Gerald @ Feb 23 2017, 05:46 PM) *
Re 2) Do you see the fuzzy shadow of almost 500m diameter 1km to the left from the slabs? I'd interprete this as an old impact crater. Over time, the craters erode due to subsequent impacts.



I used Quickmap to measure the distance from the slabs to the leftwise crater and it is only 500 m to the center of it. It is about 500 m diameter.

Being a neophyte I would have thought that the erosion of that crater would be matched by the erosion of the presumed slabs ejected from it. That looks like a lot of crater erosion to me!
But the slabs appear sharply defined.
Go to the top of the page
 
+Quote Post

32 Pages V  « < 29 30 31 32 >
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 24th February 2017 - 08:15 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.