Mars reliefs

[ispom]

I’ve seen today:
http://www.esa.int/images/324-020507-1483-6-co-01-DeuteronilusMensae_L.jpg

http://www.esa.int/SPECIALS/Mars_Express/SEMBS5V681F_0.html
a picture of Deuteronilus Mensae:
amzingly: 2000 m deep!
and the dark interior is said to be a sort of glacier debris…

sadly I see such pictures always inverse in relief,
insteed of a depression I see an elevation,
there are somebody also afflicted with that phenomenon?
fragt Ispom

[Orion]

Your not the only one I also suffer from that.

[acropolite]

Funny, when I first viewed the image I saw a depression, now it's an elevation. I've found that if I think about which direction the light is coming from then it seems to have the correct perspective.

[bojan]

It is not suffering form faulty operation of the brains ..
Simply, we are not getting enough information (both eyes are receiving the same image, no 3rd dimension info is present), so brain tries to interprete what's available, based on experience.
Try to rotate image 180 degrees, it works for me (sometimes) :-)

[glenc]

http://antwrp.gsfc.nasa.gov/apod/image/0705/marshole_hirise_big.jpg

A Hole in Mars
Credit: NASA (http://www.nasa.gov/), JPL (http://www.jpl.nasa.gov/), U. Arizona (http://hirise.lpl.arizona.edu/) Explanation: Black spots have been discovered on Mars that are so dark that nothing inside can be seen. Quite possibly, the spots (http://www.planetary.org/blog/article/00000984/) are entrances to deep underground caves (http://www.nps.gov/wica/historyculture/images/Historic_Cave_Entrance.jpg) capable of protecting Martian life (http://mars.jpl.nasa.gov/life/), where it to exist. The unusual hole pictured above was found on the slopes of the giant Martian volcano Arsia Mons (http://en.wikipedia.org/wiki/Arsia_Mons). The above image was captured three weeks ago by the HiRISE (http://en.wikipedia.org/wiki/HiRISE) instrument onboard the Mars Reconnaissance Orbiter (http://mars.jpl.nasa.gov/mro/overview/) currently circling Mars (http://antwrp.gsfc.nasa.gov/apod/ap050209.html). The holes were originally identified (http://www.lpi.usra.edu/meetings/lpsc2007/pdf/1371.pdf) on lower resolution images from the Mars Odyssey (http://mars.jpl.nasa.gov/odyssey/overview/) spacecraft, The above hole is about the size of a football field (http://en.wikipedia.org/wiki/Football_pitch) and is so deep that it is completely unilluminated (http://antwrp.gsfc.nasa.gov/apod/ap060409.html) by the Sun. Such holes and underground caves (http://en.wikipedia.org/wiki/Cave) might be prime targets for future spacecraft (http://mars.jpl.nasa.gov/missions/future/), robots (http://www-robotics.jpl.nasa.gov/), and even the next generation of human interplanetary explorers (http://en.wikipedia.org/wiki/The_Martian_Chronicles).

[ispom]

Todays APOD:

http://antwrp.gsfc.nasa.gov/apod/ap070528.html

a football-field-large hole on Mars, the entrance to a cave, in whose protection life exists? Shouldn't first Mars crew land there in the proximity?

[ispom]

well, bojan, I've tried it and so it works :thumbsup: !

rotate 180 degrees and enlarge,
and I'll see the landscape like in reality,
but if the picture rotates back,
the relief is wrong again :(

[Ric]

Tried rotating and it works a treat but I get dizzy standing on my head and it's to hard to type :rofl:

Nice image though

[ispom]

you must not rotate yourself, Ric
lets rotate the picture

you don't must diminish yourself to made the picture greater,
employ an image processing program :rofl:

[bojan]

Some more on this hole on Mars here:

http://planetary.org/blog/article/00000984

[Ric]

Methinks these holes are going to provide some fascinating discussion and speculation.

Cheers

[ballaratdragons]

Wierd how the light seems to stop abruptly only a few metres into the hole, rather than showing a fading shadow dissappearing down a shaft. Its almost like the ground is only a shelf over a large cavernous area only a few metres under the shelf.

[glenc]

Maybe someone painted the ground black! ;)

[erick]

That's the conclusion they have come to - there is significant overhang - on the sunlit side, for sure. Go inot the article and pull up the highest resolution image - it's an amazingly black void!

[bojan]

If Richard Hoagland reads this.... :scared:

[ballaratdragons]

I did Eric, that's where I noticed it the most.

I did a graphic to explain what I mean.
It seems to be like a shelved void (on the right) rather than a shaft (left)

[erick]

Sorry Ken, I missed the point you made. I agree that the overhang must be substantial - any volunteers to stand near the edge? Let's hope the rovers (if they are still mobile?) don't encounter one - don't think they carry parachutes!

[ballaratdragons]

They may need to!

[ving]

hey, thats how it looks from my backyard!

[erick]

:rofl: Cute, Ken!! I love your graphics! But the parachute has to be enormous - Mars Atmosphere is on average less than 1% of Earth's!

[ballaratdragons]

But it won't fit down the hole :sadeyes:

[bojan]

More on holes on Mars here:
http://www.universetoday.com/2007/08/31/not-pits-tubes/#more-11696
It seems they are actually very deep pits.... but the bottom is still not visible..

[ispom]

do you remember ?

a deep hole was found on Mars

http://www.space.com/scienceastronomy/070605_mars_hole.html (http://www.space.com/scienceastronomy/070605_mars_hole.html)

now there is a new view of the Dark Pit on Arsia Mons !

http://www.2-0.scienceticker.info/wp-content/uploads/2007/08/mars-hirise-loch.jpg (http://www.2-0.scienceticker.info/wp-content/uploads/2007/08/mars-hirise-loch.jpg)http://hirise.lpl.arizona.edu/PSP_004847_1745 (http://hirise.lpl.arizona.edu/PSP_004847_1745)

From the shadow of the rim cast onto the wall of the pit we can calculate that the pit is at least 78 meters deep,
presumably an “einsturzkrater”
(can’t translate, sorry) perhaps: a crater originated by collapsing of the surface

and now:
more entrances to caves along the slope of a Martian volcano discovered,
now we know 7 such holes

http://www.jpl.nasa.gov/news/news.cfm?release=2007-106

[Ric]

Fantastic stuff Ispom, I cant help but wonder what's down there. I reckon 78 metres is enough to protect a lot of things from the harsh surface.

Cheers

[glenc]

APOD today has the same image.
http://antwrp.gsfc.nasa.gov/apod/
Explanation: In a close-up (http://hirise.lpl.arizona.edu/PSP_004847_1745) from the HiRISE (http://hirise.lpl.arizona.edu/index.php) instrument onboard the Mars Reconnaissance Orbiter, this mysterious dark pit, about 150 meters across, lies on the north slope of ancient martian (http://www.lukew.com/marsgeo/index.html) volcano Arsia Mons (http://photojournal.jpl.nasa.gov/catalog/PIA02337). Lacking raised rims and other impact crater characteristics, this pit and others like it (http://mars.jpl.nasa.gov/odyssey/newsroom/pressreleases/20070921a.html) were originally identified in visible light and infrared images from the Mars Odyssey and Mars Global Surveyor spacecraft. While the visible light images showed only darkness within (http://antwrp.gsfc.nasa.gov/apod/ap070528.html), infrared thermal signatures (http://www.nasa.gov/mission_pages/odyssey/images/cave4.html) indicated that the openings penetrated deep under the martian surface and perhaps were skylights to underground caverns. In this later image, the pit wall is partially illuminated by sunlight and seen to be nearly vertical, though the bottom, at least 78 meters below, is still not visible. The dark martian pits are thought to be related to collapse pits (http://hvo.wr.usgs.gov/gallery/kilauea/erz/devilsthroat.html) in the lava flow, similar (http://hvo.wr.usgs.gov/gallery/kilauea/erz/upper/30424305-044_large.jpg) to Hawaiian volcano pit craters (http://volcanoes.usgs.gov/Products/Pglossary/PitCrater.html).

[Dujon]

How intriguing. Thanks for all the various links provided.

Looking at the image referenced by Glen (and others) I can't visualise a geometry which would allow for the object to be a shaft. The lighting - to my mind at least - seems to signify a hole through a significant amount of rock (or whatever) into a void.

Most of the seven images are close to circular. Why? Perhaps these are collapsed domes or, maybe, even caused by a meteorite punching through the skin of the volcano. In the latter case I would think that the depth of the 'hole' would have to be significant otherwise the pressure wave produced by its final impact would surely have caused some ejecta to be visible. A small impacting body which, on contact (after piercing the upper skin) caused the weakened area to collapse also seems unlikely as I would again suspect that some ejecta would be clearly visible.

The image of 'Jeanne' or 'F' in the montage of the seven sisters does appear to have some outflow, though whether that is ejecta or lava flow I have no idea.

Definitely intriguing.


*edit*

Sorry, Ispom, I forgot to include that I too have the problem of "up" and "down" when it comes to some images. At times it's hard to convince the mind that it's giving me wrong information.