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Main
Date: 28 May 2007 13:23:21
From: Sam Wormley
Subject: Problem with this image from MRO?
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Look at the enlarged image from MRO
http://antwrp.gsfc.nasa.gov/apod/ap070528.html
http://antwrp.gsfc.nasa.gov/apod/image/0705/marshole_hirise_big.jpg
It looks like it suffers from "vibration" or a double image... something
is wrong. Any ideas.
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Date: 30 May 2007 09:46:25
From: Ben
Subject: Re: Problem with this image from MRO?
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On May 30, 9:21 am, Chris L Peterson <c...@alumni.caltech.edu > wrote:
> I don't have any sense of the sedimentation rate on Mars from dust
> storms, or especially how dust would settle through small holes. Maybe
> the holes are young, but then, wouldn't you expect to see a range of
> features of different ages? All these holes look about the same, pretty
> round, clean top edge. There's nothing that looks like a cavern mostly
> filled in. That sort of makes me think the features were all produced
> around the same time, presumably not long after the caverns formed. But
> who knows? It's all very curious, that's for sure!
It's almost preposterous. Just when the belts of Jupiter start really
misbehaving this thing shows up. This has to be one of the
strangest planetary images I've ever seen.
Ben
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Date: 29 May 2007 17:19:30
From: thad@thadlabs.com
Subject: Re: Problem with this image from MRO?
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On May 28, 7:29 pm, "Alan French" <adfrenchremoveallt...@nycap.rr.com >
wrote:
> We're in trouble now - remember the "Hollow Earth" folks?
That's for sure; wait 'til Richard C. Hoaxland finds out about this --
he'll likely
publicize it more than the "face". :-)
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Date: 28 May 2007 18:57:42
From: Ben
Subject: Re: Problem with this image from MRO?
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On May 28, 6:41 pm, Chris L Peterson <c...@alumni.caltech.edu > wrote:
> On 28 May 2007 16:09:44 -0700, Ben <bet71...@netzero.com> wrote:
>
> If you look at the full resolution image, you can see that the area
> north of the hole appears to be sand dunes. I don't see anything to
> suggest an impact (other than the shape of the hole), but it's
> interesting to consider what's different on the north side to produce
> these small dunes. It's as if the entire area is slightly raised or
> depressed, affecting the prevailing winds. I don't know how fine the
> topographic data for this area is. Maybe a big hole on flat terrain can
> also affect the local air flow?
The question may come down to, "Where on Arsia Mons is the
hole located?" I didn't think the Shield Volcanos were noted
for their sand dunes but then again Mars is a sandy place.
If the hole is on the South slope then the tops of the dunes would
perhaps slide off into the pit causing fresh material to be exposed.
Would this material be brighter than the surrounding dunes?
I think it's likely.
Thinking, Thinking...
Ben
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Date: 28 May 2007 22:29:27
From: Alan French
Subject: Re: Problem with this image from MRO?
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We're in trouble now - remember the "Hollow Earth" folks?
Clear skies, Alan
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Date: 28 May 2007 16:09:44
From: Ben
Subject: Re: Problem with this image from MRO?
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On May 28, 8:23 am, Sam Wormley <sworml...@mchsi.com > wrote:
> Look at the enlarged image from MRO
> http://antwrp.gsfc.nasa.gov/apod/ap070528.html
> http://antwrp.gsfc.nasa.gov/apod/image/0705/marshole_hirise_big.jpg
>
> It looks like it suffers from "vibration" or a double image... something
> is wrong. Any ideas.
To compound the difficulties it appears that the North side of the
hole has a certain rayed effect from an impactor. It's almost as
if an object struck the top of an evacuated lava chamber and caved
in.
My $0.02
Ben
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Date: 28 May 2007 23:41:32
From: Chris L Peterson
Subject: Re: Problem with this image from MRO?
|
On 28 May 2007 16:09:44 -0700, Ben <bet71743@netzero.com > wrote:
>To compound the difficulties it appears that the North side of the
>hole has a certain rayed effect from an impactor. It's almost as
>if an object struck the top of an evacuated lava chamber and caved
>in.
If you look at the full resolution image, you can see that the area
north of the hole appears to be sand dunes. I don't see anything to
suggest an impact (other than the shape of the hole), but it's
interesting to consider what's different on the north side to produce
these small dunes. It's as if the entire area is slightly raised or
depressed, affecting the prevailing winds. I don't know how fine the
topographic data for this area is. Maybe a big hole on flat terrain can
also affect the local air flow?
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
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Date: 28 May 2007 09:30:43
From: Greg Crinklaw
Subject: Re: Problem with this image from MRO?
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Sam Wormley wrote:
> Look at the enlarged image from MRO
> http://antwrp.gsfc.nasa.gov/apod/ap070528.html
> http://antwrp.gsfc.nasa.gov/apod/image/0705/marshole_hirise_big.jpg
>
> It looks like it suffers from "vibration" or a double image... something
> is wrong. Any ideas.
I don't think there's anything wrong. It's a perception effect due to
the large amount of detail that is just at or below the resolution of
the image displayed at that size.
Greg
--
Greg Crinklaw
Astronomical Software Developer
Cloudcroft, New Mexico, USA (33N, 106W, 2700m)
SkyTools: http://www.skyhound.com/cs.html
Observing: http://www.skyhound.com/sh/skyhound.html
Comets: http://www.skyhound.com/sh/comets.html
To reply take out your eye
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Date: 28 May 2007 14:49:57
From: Davoud
Subject: Re: Problem with this image from MRO?
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Sam Wormley wrote:
> Look at the enlarged image from MRO
> http://antwrp.gsfc.nasa.gov/apod/ap070528.html
> http://antwrp.gsfc.nasa.gov/apod/image/0705/marshole_hirise_big.jpg
>
> It looks like it suffers from "vibration" or a double image... something
> is wrong. Any ideas.
It does indeed have that jittery look, and since no other photo I have
seen from MRO has that look, it would appear that something is wrong
with the image or the image processing. It could, however be an
illusion caused by the nature of the terrain and/or the angle of the
light.
Or the photo might have been doctored by NASA to hide from us the
statue of Elvis that is just up-slope from the hole.
Davoud
--
usenet *at* davidillig dawt com
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Date: 28 May 2007 16:57:48
From: David Nakamoto
Subject: Re: Problem with this image from MRO?
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Davoud wrote:
> Sam Wormley wrote:
>
>> Look at the enlarged image from MRO
>> http://antwrp.gsfc.nasa.gov/apod/ap070528.html
>> http://antwrp.gsfc.nasa.gov/apod/image/0705/marshole_hirise_big.jpg
>>
>> It looks like it suffers from "vibration" or a double image... something
>> is wrong. Any ideas.
>
> It does indeed have that jittery look, and since no other photo I have
> seen from MRO has that look, it would appear that something is wrong
> with the image or the image processing. It could, however be an
> illusion caused by the nature of the terrain and/or the angle of the
> light.
>
> Or the photo might have been doctored by NASA to hide from us the
> statue of Elvis that is just up-slope from the hole.
>
> Davoud
>
Look carefully. Craters are not duplicated. It is the nature of the
terrain and not a product of image processing that causes the embossed
look. There is nothing wrong with the image.
--- Dave
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Date: 28 May 2007 18:37:30
From: Davoud
Subject: Re: Problem with this image from MRO?
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Sam Wormley:
> >> Look at the enlarged image from MRO
> >> http://antwrp.gsfc.nasa.gov/apod/ap070528.html
> >> http://antwrp.gsfc.nasa.gov/apod/image/0705/marshole_hirise_big.jpg
> >>
> >> It looks like it suffers from "vibration" or a double image... something
> >> is wrong. Any ideas.
Davoud:
> > It does indeed have that jittery look, and since no other photo I have
> > seen from MRO has that look, it would appear that something is wrong
> > with the image or the image processing. It could, however be an
> > illusion caused by the nature of the terrain and/or the angle of the
> > light.
> >
> > Or the photo might have been doctored by NASA to hide from us the
> > statue of Elvis that is just up-slope from the hole.
David Nakamoto:
> Look carefully. Craters are not duplicated. It is the nature of the
> terrain and not a product of image processing that causes the embossed
> look. There is nothing wrong with the image.
Thank you. Er, uh, I /did/ look carefully. "...it would /appear/ that
something is wrong..." "...could, however be an /illusion/ ..."
Let me assure you that if I were convinced that something was wrong
with the image I would have said "...there is something wrong with the
image..." or words to that effect. I have a really tight grasp on the
difference between "appears to be" and "is." And I know what "is" is
:--)
Davoud
--
usenet *at* davidillig dawt com
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Date: 28 May 2007 13:38:53
From: Chris L Peterson
Subject: Re: Problem with this image from MRO?
|
On Mon, 28 May 2007 13:23:21 GMT, Sam Wormley <swormley1@mchsi.com >
wrote:
>Look at the enlarged image from MRO
> http://antwrp.gsfc.nasa.gov/apod/ap070528.html
> http://antwrp.gsfc.nasa.gov/apod/image/0705/marshole_hirise_big.jpg
>
>It looks like it suffers from "vibration" or a double image... something
>is wrong. Any ideas.
I don't see anything I would describe that way. The Sun was only 38°
above the horizon, so the low-relief terrain has a sort of embossed
look. Maybe that's what you are seeing?
The full resolution image of the hole,
http://hiroc.lpl.arizona.edu/images/2007/details/cut/PSP_3647_1745_cut_b.jpg
shows details around the edge very clearly, with no sign of any imaging
problems.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
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Date: 30 May 2007 03:13:00
From: George
Subject: Re: Problem with this image from MRO?
|
"Chris L Peterson" <clp@alumni.caltech.edu > wrote in message
news:tlml53ppjot8l9kcasea4s4mt8vqmtausp@4ax.com...
> On Mon, 28 May 2007 13:23:21 GMT, Sam Wormley <swormley1@mchsi.com>
> wrote:
>
>>Look at the enlarged image from MRO
>> http://antwrp.gsfc.nasa.gov/apod/ap070528.html
>> http://antwrp.gsfc.nasa.gov/apod/image/0705/marshole_hirise_big.jpg
>>
>>It looks like it suffers from "vibration" or a double image... something
>>is wrong. Any ideas.
>
> I don't see anything I would describe that way. The Sun was only 38°
> above the horizon, so the low-relief terrain has a sort of embossed
> look. Maybe that's what you are seeing?
>
> The full resolution image of the hole,
> http://hiroc.lpl.arizona.edu/images/2007/details/cut/PSP_3647_1745_cut_b.jpg
> shows details around the edge very clearly, with no sign of any imaging
> problems.
>
> _________________________________________________
>
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
Chris, I downloaded the image at your link, cropped it, and enhanced it
using the shadow/highlight filter in photoshop, and here is my result:
http://i132.photobucket.com/albums/q9/jryates/hole.jpg
If you open it and zoom in, it appears that you can see a little more
detail inside the hole, though admittedly not much. But it does appear
that there is enough detail there to say that it doesn't go to china (or
what passes for such on Mars)! But it does appear to be quite deep. Also
note the area just to the north of ther image (assuming that north is
towards the top of the image). It looks to me as if there is a large
shallow depression there filled with scalloping sand dunes, as if the
bedrock is sinking or sagging a bit, so the karst in this terrain may even
be more extensive than the hole by itself would seem to indicate. Just my
two cents worth.
George
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Date: 30 May 2007 13:13:21
From: Chris L Peterson
Subject: Re: Problem with this image from MRO?
|
On Wed, 30 May 2007 03:13:00 -0400, "George" <george@yourservice.com >
wrote:
>Chris, I downloaded the image at your link, cropped it, and enhanced it
>using the shadow/highlight filter in photoshop, and here is my result:
>
>http://i132.photobucket.com/albums/q9/jryates/hole.jpg
>
>If you open it and zoom in, it appears that you can see a little more
>detail inside the hole, though admittedly not much.
I think you're just seeing noise, especially likely if you're working
from the JPEG image I linked. The right side of that same image is a
highly stretched version made by the HiRISE image processing team, and
they concluded that there was nothing in the sensor data for the
interior of the hole except noise. I expect they know the performance
details of their instrument well enough to say that definitively.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
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Date: 30 May 2007 14:05:09
From: George
Subject: Re: Problem with this image from MRO?
|
"Chris L Peterson" <clp@alumni.caltech.edu > wrote in message
news:bttq53lpbudjbiv43j29kfrkmo5062pm67@4ax.com...
> On Wed, 30 May 2007 03:13:00 -0400, "George" <george@yourservice.com>
> wrote:
>
>>Chris, I downloaded the image at your link, cropped it, and enhanced it
>>using the shadow/highlight filter in photoshop, and here is my result:
>>
>>http://i132.photobucket.com/albums/q9/jryates/hole.jpg
>>
>>If you open it and zoom in, it appears that you can see a little more
>>detail inside the hole, though admittedly not much.
>
> I think you're just seeing noise, especially likely if you're working
> from the JPEG image I linked. The right side of that same image is a
> highly stretched version made by the HiRISE image processing team, and
> they concluded that there was nothing in the sensor data for the
> interior of the hole except noise. I expect they know the performance
> details of their instrument well enough to say that definitively.
>
> _________________________________________________
>
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
The thought did occur to me that it was just noise. I just wanted to get
your input. Thanks, Chris.
George
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Date: 30 May 2007 02:51:38
From: George
Subject: Re: Problem with this image from MRO?
|
"Chris L Peterson" <clp@alumni.caltech.edu > wrote in message
news:tlml53ppjot8l9kcasea4s4mt8vqmtausp@4ax.com...
> On Mon, 28 May 2007 13:23:21 GMT, Sam Wormley <swormley1@mchsi.com>
> wrote:
>
>>Look at the enlarged image from MRO
>> http://antwrp.gsfc.nasa.gov/apod/ap070528.html
>> http://antwrp.gsfc.nasa.gov/apod/image/0705/marshole_hirise_big.jpg
>>
>>It looks like it suffers from "vibration" or a double image... something
>>is wrong. Any ideas.
>
> I don't see anything I would describe that way. The Sun was only 38°
> above the horizon, so the low-relief terrain has a sort of embossed
> look. Maybe that's what you are seeing?
>
> The full resolution image of the hole,
> http://hiroc.lpl.arizona.edu/images/2007/details/cut/PSP_3647_1745_cut_b.jpg
> shows details around the edge very clearly, with no sign of any imaging
> problems.
>
> _________________________________________________
>
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
What is amazing about that image is that if the hole is 300 meters across,
as advertized, and it is that dark, that is one deep hole! But then, if
the sun angle is merely grazing, that may account for not being able to see
the bottom. I've seen a lot of deep sink holes (I live in cave country),
and I've never seen one that big or that dark that was so wide open to the
sky. What say you?
George
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Date: 30 May 2007 13:20:42
From: Chris L Peterson
Subject: Re: Problem with this image from MRO?
|
On Wed, 30 May 2007 02:51:38 -0400, "George" <george@yourservice.com >
wrote:
>What is amazing about that image is that if the hole is 300 meters across,
>as advertized, and it is that dark, that is one deep hole! But then, if
>the sun angle is merely grazing, that may account for not being able to see
>the bottom. I've seen a lot of deep sink holes (I live in cave country),
>and I've never seen one that big or that dark that was so wide open to the
>sky. What say you?
I don't think the structure is right for a sinkhole. There are a number
of these holes in the area, and none seem to show side walls. The idea
that these are skylights- surface punctures to underground caverns-
makes a lot of sense. This 200 meter diameter hole is very large (the
others are much smaller), and I'm inclined to think such a skylight on
Earth would be unlikely. But very large unsupported caverns seem more
likely on Mars with its much lower gravity.
Of course, the darkness is emphasized by the low sun angle. Given the
near equatorial latitude of this feature, I presume it is possible to
get an image with a very high sun angle. I don't know how long we'll
have to wait for the right combination of orbiter position and sun
position to get one, though.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
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Date: 30 May 2007 09:43:26
From: Dennis Woos
Subject: Re: Problem with this image from MRO?
|
> I don't think the structure is right for a sinkhole. There are a number
> of these holes in the area, and none seem to show side walls. The idea
> that these are skylights- surface punctures to underground caverns-
> makes a lot of sense. This 200 meter diameter hole is very large (the
> others are much smaller), and I'm inclined to think such a skylight on
> Earth would be unlikely. But very large unsupported caverns seem more
> likely on Mars with its much lower gravity.
>
Given the huge Martian dust storms, wouldn't it be reasonable to expect that
any cavern would have filled up over the (millions/tens of millions/hundreds
of millions/billions?) of years since such a cavern could have formed?
Maybe the cavern is geologically old, whereas the skylight is a relatively
recent excavation?
Dennis
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Date: 30 May 2007 14:21:39
From: Chris L Peterson
Subject: Re: Problem with this image from MRO?
|
On Wed, 30 May 2007 09:43:26 -0400, "Dennis Woos" <dpwoos@gmavt.net >
wrote:
>Given the huge Martian dust storms, wouldn't it be reasonable to expect that
>any cavern would have filled up over the (millions/tens of millions/hundreds
>of millions/billions?) of years since such a cavern could have formed?
>Maybe the cavern is geologically old, whereas the skylight is a relatively
>recent excavation?
I don't have any sense of the sedimentation rate on Mars from dust
storms, or especially how dust would settle through small holes. Maybe
the holes are young, but then, wouldn't you expect to see a range of
features of different ages? All these holes look about the same, pretty
round, clean top edge. There's nothing that looks like a cavern mostly
filled in. That sort of makes me think the features were all produced
around the same time, presumably not long after the caverns formed. But
who knows? It's all very curious, that's for sure!
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
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Date: 28 May 2007 19:04:03
From: Sam Wormley
Subject: Re: Problem with this image from MRO?
|
Chris L Peterson wrote:
> On Mon, 28 May 2007 13:23:21 GMT, Sam Wormley <swormley1@mchsi.com>
> wrote:
>
>> Look at the enlarged image from MRO
>> http://antwrp.gsfc.nasa.gov/apod/ap070528.html
>> http://antwrp.gsfc.nasa.gov/apod/image/0705/marshole_hirise_big.jpg
>>
>> It looks like it suffers from "vibration" or a double image... something
>> is wrong. Any ideas.
>
> I don't see anything I would describe that way. The Sun was only 38°
> above the horizon, so the low-relief terrain has a sort of embossed
> look. Maybe that's what you are seeing?
>
> The full resolution image of the hole,
> http://hiroc.lpl.arizona.edu/images/2007/details/cut/PSP_3647_1745_cut_b.jpg
> shows details around the edge very clearly, with no sign of any imaging
> problems.
>
> _________________________________________________
>
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
|
| | | |
Date: 28 May 2007 13:14:10
From: SkySea
Subject: Re: Problem with this image from MRO?
|
>> The full resolution image of the hole,
>> http://hiroc.lpl.arizona.edu/images/2007/details/cut/PSP_3647_1745_cut_b.jpg
>> shows details around the edge very clearly, with no sign of any imaging
>> problems.
Sorry about not attributing, but I couldn't follow who posted the link
above.
This image is to me stranger when seen in greater detail.
It's more than just a deep hole. It eppears to me to be an unsupported
rim to a cavern. If it were just a deep hole, the side of the shaft
would be illuminated on the upper-right side. Other shadows (in the
lower-scale images) indicate the lighting is not particularly
ooblique, so it's not as if the lower-left edge is casting a shadow
across the bowl and reaching up the upper-right side. And even if it
did, the shadow would cast an elliptical shape along the wall, not
follow it at a consistent depth.
But what process could create, and what material could support such a
structure?
Alternatively and even weirder, the bottom edge appears to be sharply
cut off, as if there was a floor of perfectly light-absorbent
material.
So what is this?
=============
- Dale Gombert (SkySea at aol.com)
122.38W, 47.58N, W. Seattle, WA
http://flavorj.com/~skysea
|
| | | | |
Date: 28 May 2007 20:31:01
From: Sam Wormley
Subject: Re: Problem with this image from MRO?
|
SkySea wrote:
>>> The full resolution image of the hole,
>>> http://hiroc.lpl.arizona.edu/images/2007/details/cut/PSP_3647_1745_cut_b.jpg
>>> shows details around the edge very clearly, with no sign of any imaging
>>> problems.
>
> Sorry about not attributing, but I couldn't follow who posted the link
> above.
>
> This image is to me stranger when seen in greater detail.
>
> It's more than just a deep hole. It eppears to me to be an unsupported
> rim to a cavern. If it were just a deep hole, the side of the shaft
> would be illuminated on the upper-right side. Other shadows (in the
> lower-scale images) indicate the lighting is not particularly
> ooblique, so it's not as if the lower-left edge is casting a shadow
> across the bowl and reaching up the upper-right side. And even if it
> did, the shadow would cast an elliptical shape along the wall, not
> follow it at a consistent depth.
>
> But what process could create, and what material could support such a
> structure?
>
> Alternatively and even weirder, the bottom edge appears to be sharply
> cut off, as if there was a floor of perfectly light-absorbent
> material.
>
> So what is this?
> =============
> - Dale Gombert (SkySea at aol.com)
> 122.38W, 47.58N, W. Seattle, WA
> http://flavorj.com/~skysea
Missing detail of the "hole" is mostly likely due to insufficient
dynamic range in the imaging system, not exotic structure of the
"hole".
|
| | | | | |
Date: 28 May 2007 21:07:21
From: Chris L Peterson
Subject: Re: Problem with this image from MRO?
|
On Mon, 28 May 2007 20:31:01 GMT, Sam Wormley <swormley1@mchsi.com >
wrote:
> Missing detail of the "hole" is mostly likely due to insufficient
> dynamic range in the imaging system, not exotic structure of the
> "hole".
I'm sure that's part of it, but the geometry of the hole is still pretty
interesting. Given the sun angle, the eastern side of the hole should be
lit to a depth of about 50 meters. The horizontal resolution of the
image is 76 cm, so that suggests that no part of the hole's wall is
extending inward as much as a meter for the first 50 meters of depth.
It's also possible that the angle of the imager, or the angle of the
hole is such that the eastern wall can't be seen. In any case, something
a bit "exotic" may still be going on.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
|
| | | | | | |
Date: 28 May 2007 15:44:56
From: Milton Aupperle
Subject: Re: Problem with this image from MRO?
|
In article <0rgm53lf6v22bj8ji09cs6nk5o8e8usgrm@4ax.com >, Chris L
Peterson <clp@alumni.caltech.edu > wrote:
> On Mon, 28 May 2007 20:31:01 GMT, Sam Wormley <swormley1@mchsi.com>
> wrote:
>
> > Missing detail of the "hole" is mostly likely due to insufficient
> > dynamic range in the imaging system, not exotic structure of the
> > "hole".
>
> I'm sure that's part of it, but the geometry of the hole is still pretty
> interesting. Given the sun angle, the eastern side of the hole should be
> lit to a depth of about 50 meters. The horizontal resolution of the
> image is 76 cm, so that suggests that no part of the hole's wall is
> extending inward as much as a meter for the first 50 meters of depth.
> It's also possible that the angle of the imager, or the angle of the
> hole is such that the eastern wall can't be seen. In any case, something
> a bit "exotic" may still be going on.
My guess is your looking at a breached lava tube (which would be
roughly elliptical in profile) or perhaps the top of a collapsed cavern
(? magma chamber ?) and there may not be any vertical walls visible.
I can think of several examples of this that I have seen personally in
my travels as a mining geologist. A good one is the "Craters of the
Moon" park in Idaho which had some really great breached and collapsed
lava tubes. I remember one you could walk through (about 15 meters wide
/ 10 meters tall diameter) that had a hole in the top and you could
look up at and see the sky.
My $0.02 CDN opinion..
Milton Aupperle
http://www.outcastsoft.com/AstroImages/AstroIndex.html
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Date: 28 May 2007 21:50:03
From: Chris L Peterson
Subject: Re: Problem with this image from MRO?
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On Mon, 28 May 2007 15:44:56 -0600, Milton Aupperle <spam@mustdie.com >
wrote:
>My guess is your looking at a breached lava tube (which would be
>roughly elliptical in profile) or perhaps the top of a collapsed cavern
>(? magma chamber ?) and there may not be any vertical walls visible.
>
>I can think of several examples of this that I have seen personally in
>my travels as a mining geologist. A good one is the "Craters of the
>Moon" park in Idaho which had some really great breached and collapsed
>lava tubes. I remember one you could walk through (about 15 meters wide
>/ 10 meters tall diameter) that had a hole in the top and you could
>look up at and see the sky.
Yeah, I've seen those kind of structures at Craters of the Moon, too.
This would have to be a good deal bigger than anything I've heard about
on Earth, but of course, with the lower gravity on Mars such structures
could be larger.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
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Date: 28 May 2007 13:44:48
From: SkySea
Subject: Re: Problem with this image from MRO?
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I find that explanation far more plausible than the simple "deep hole"
concept.
> Sam Wormley <swormley1@mchsi.com> wrote:
> Missing detail of the "hole" is mostly likely due to insufficient
> dynamic range in the imaging system, not exotic structure of the
> "hole".
=============
- Dale Gombert (SkySea at aol.com)
122.38W, 47.58N, W. Seattle, WA
http://flavorj.com/~skysea
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