APOD: White Rock Fingers on Mars (2011 Oct 30)

Comments and questions about the APOD on the main view screen.

APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby APOD Robot » Sun Oct 30, 2011 4:06 am

Image White Rock Fingers on Mars

Explanation: What caused this unusual light rock formation on Mars? Intrigued by the possibility that they could be salt deposits left over as an ancient lakebed dried-up, detailed studies of these fingers now indicate a more mundane possibility: volcanic ash. Studying the exact color of the formation indicated the possible volcanic origin. The light material appears to have eroded away from surrounding area, indicating a very low-density substance. The stark contrast between the rocks and the surrounding sand is compounded by the unusual darkness of the sand. The above picture was taken with the Thermal Emission Imaging System on the Mars Odyssey spacecraft currently orbiting Mars. The image spans about 10 kilometers inside a larger crater.

<< Previous APODDiscuss Any APOD Next APOD >>
User avatar
APOD Robot
Otto Posterman
 
Posts: 1710
Joined: Fri Dec 04, 2009 3:27 am

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby Beyond » Sun Oct 30, 2011 4:22 am

Good lead-in for tomorrow's spooky sky. Too bad they aren't folsilized bones. That would be an even better lead-in. And also something that you would be glad is on mars and NOT earth!
To find the Truth, you must go Beyond
User avatar
Beyond
Milliways Pundit
 
Posts: 6098
Joined: Tue Aug 04, 2009 11:09 am
Location: BEYONDER LAND

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby enebrad2@comcast.net » Sun Oct 30, 2011 5:20 am

My compliments to Emily Lakdawalla for providing such a clear and understandable explanation of the White Rock images (APOD April 7, 2008). Her non-technical discussion is a welcome relief.
enebrad2@comcast.net
 

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby Ann » Sun Oct 30, 2011 6:08 am

They have found the Abominable Snowman!!! :shock:

(Chris, you sure that isn't you?)

Ann
Color Commentator
User avatar
Ann
4725 Å
 
Posts: 5396
Joined: Sat May 29, 2010 5:33 am

White Fang Rocks on Soupy Sales

Postby neufer » Sun Oct 30, 2011 12:03 pm

Click to play embedded YouTube video.
Art Neuendorffer
User avatar
neufer
Abstruse Allusion Artificer
 
Posts: 11394
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby orin stepanek » Sun Oct 30, 2011 12:55 pm

That last link was really something with the formation inside the crater. 8-)
Orin

Smile today; tomorrow's another day!
User avatar
orin stepanek
Plutopian
 
Posts: 4174
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby MGTS24 » Sun Oct 30, 2011 3:35 pm

Surely if this image was created using thermal imaging, the various tones correspond to the temperature of the different materials, and not 'light and dark' in repect to the visible spectrum. Or is the correspondence between tone and temperature always very close with lithic materials?

Curious
Michael
MGTS24
Asternaut
 
Posts: 1
Joined: Sun Oct 30, 2011 3:23 pm

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby NoelC » Sun Oct 30, 2011 3:56 pm

Good Halloween choice!

orin stepanek wrote:That last link was really something with the formation inside the crater. 8-)

What is it about Mars that so many of the images come out looking "inside-out" (meaning that things that should look like indentations seem to be easily misinterpreted as extrusions)?

-Noel
User avatar
NoelC
Creepy Spock
 
Posts: 871
Joined: Sun Nov 20, 2005 2:30 am
Location: South Florida, USA; I just work in (cyber)space

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby Chris Peterson » Sun Oct 30, 2011 4:22 pm

NoelC wrote:What is it about Mars that so many of the images come out looking "inside-out" (meaning that things that should look like indentations seem to be easily misinterpreted as extrusions)?

It's just that old crater-and-hill illusion, the product of our lighting expectations. The thing with these Mars images is that there is lots of topographic structure, and for the most part, no attempt to orient the images so that the lighting direction is "normal". And of course, there is usually nothing else in the images to provide other cues for our perception.

Optical00251.png

Optical00261.png
You do not have the required permissions to view the files attached to this post.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
User avatar
Chris Peterson
Abominable Snowman
 
Posts: 8717
Joined: Wed Jan 31, 2007 11:13 pm
Location: Colorado, USA

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby Myke » Sun Oct 30, 2011 4:29 pm

Hell, as any self-respecting genius in Ancient Aliens or UFO watchers knows those tracks are Mars Dino-tracks, of course. Its another NASA conspiracy. [Like my spelling?]...LMAO waiting for the conspiracy books to begin to breed. BTW...great picture...science beats ignorance forever!
Myke
 

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby NoelC » Sun Oct 30, 2011 8:11 pm

Chris Peterson wrote:no attempt to orient the images so that the lighting direction is "normal"

You'd think the "normal" lighting direction would be from above, so why do I see your first image as bumps and the second as divots when I first look at it? Is my brain just upside-down? :) In all seriousness, the other day I had a DEVIL of a time seeing those dry ice pits on mars as anything but raised plateus.

-Noel
User avatar
NoelC
Creepy Spock
 
Posts: 871
Joined: Sun Nov 20, 2005 2:30 am
Location: South Florida, USA; I just work in (cyber)space

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby owlice » Sun Oct 30, 2011 8:38 pm

Chris Peterson wrote:
Optical00251.png

Optical00261.png

Chris, you have the coolest Legos! :D
A closed mouth gathers no foot.
User avatar
owlice
Guardian of the Codes
 
Posts: 7869
Joined: Wed Aug 04, 2004 4:18 pm
Location: Washington, DC

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby Beyond » Sun Oct 30, 2011 10:40 pm

NoelC wrote:
Chris Peterson wrote:no attempt to orient the images so that the lighting direction is "normal"

You'd think the "normal" lighting direction would be from above, so why do I see your first image as bumps and the second as divots when I first look at it? Is my brain just upside-down? :) In all seriousness, the other day I had a DEVIL of a time seeing those dry ice pits on mars as anything but raised plateus.

-Noel

:lol: I see the first ones as divots and the second one as bumps.
To find the Truth, you must go Beyond
User avatar
Beyond
Milliways Pundit
 
Posts: 6098
Joined: Tue Aug 04, 2009 11:09 am
Location: BEYONDER LAND

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby saturn2 » Sun Oct 30, 2011 10:58 pm

Image of Mars Odyssey spacecraft.
I think that this material has a volcan origin for the low-density and white color light.
A rover "saw" a rock look like this image,too.
saturn2
 

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby ingridkern » Mon Oct 31, 2011 1:16 am

Obviously, this is Mars' bony , outstretched hand, Trick-or-Treating at Earth's door. Happy Hallowe'en y'all
ingridkern
 

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby mactavish » Mon Oct 31, 2011 4:06 am

Beyond wrote:
NoelC wrote:
Chris Peterson wrote:no attempt to orient the images so that the lighting direction is "normal"

You'd think the "normal" lighting direction would be from above, so why do I see your first image as bumps and the second as divots when I first look at it? Is my brain just upside-down? :) In all seriousness, the other day I had a DEVIL of a time seeing those dry ice pits on mars as anything but raised plateus.

-Noel

:lol: I see the first ones as divots and the second one as bumps.


Copy either image to your computer and rotate it 180 (turn upside down). It will then look just like the other image. (Or, stand on your head to view it if you prefer.) Best I can figure, we are just accustomed to seeing things usually lit from above. In that regard, “normal” is nothing more than “customary”.
mactavish
 

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby DavidLeodis » Mon Oct 31, 2011 11:38 am

Ann wrote:They have found the Abominable Snowman!!! :shock:

(Chris, you sure that isn't you?)

Ann


Not YET I think. :)
User avatar
DavidLeodis
A Tiger Named Lion
 
Posts: 718
Joined: Mon May 01, 2006 1:00 pm

Re: APOD: White Rock Fingers on Mars (2011 Oct 30)

Postby iamlucky13 » Tue Nov 01, 2011 1:09 am

MGTS24 wrote:Surely if this image was created using thermal imaging, the various tones correspond to the temperature of the different materials, and not 'light and dark' in repect to the visible spectrum. Or is the correspondence between tone and temperature always very close with lithic materials?

Curious
Michael


Your understanding is a little off, although to be fair, most people don't realize that "infrared" is a very, very broad description of a type of light that can be interpreted to include anything with a longer wavelength than red (infra = beyond...beyond red), although it's usually considered more limited than that.

Measuring in nanometers (nm = billionths of a meter), the deepest red a human can perceive is around 750-790 nm (can vary person-to-person).

Beyond that, is the so called near-infrared (790 nm to 1400 nm) band. Our eyes aren't sensitive electromagnetic radiation at these wavelengths, but generally, it behaves very similar to visible light (reflects off most objects...only very hot objects radiate these wavelengths...things that are just barely not hot enough to visibly glow).

There's two bands of mid-infrared - from 1400nm to 3000nm, to which the atmosphere is opaque, because water vapor in the atmosphere acts absorbs them, acting like a smoke screen to these wavelengths, and from 3000nm to 8000nm. This latter band is getting into what the type of infrared you're thinking of known as thermal infrared - where objects are visible based on their radiation of heat, but typically only if they're hotter than room temperature.

Finally you have thermal infrared, from 8,000nm to 15,000nm (above 15,000nm, most electromagnetic radiation is again absorbed by water vapor until you get down to the microwave radio wavelengths), or about 10-20 times the wavelength of visible light. Objects at room temperature radiate strongly enough in the thermal infrared spectrum to be detectable.

Anyways, although the name of the camera is the "Thermal EMission Imaging System" (THEMIS), it actually has the ability to detect light from all of the above bands, including visible light.

The image from this APOD was taken in a visible or near visible wavelength, so it is reflections of incoming visible or infrared light, just like taking a picture with a camera.

However, your original premise is correct - if this really were an image of emitted thermal radiation, the brightness would be heavily affected by temperature.
"Any man whose errors take ten years to correct is quite a man." ~J. Robert Oppenheimer (speaking about Albert Einstein)
User avatar
iamlucky13
Commander
 
Posts: 515
Joined: Thu May 25, 2006 7:28 pm
Location: Seattle, WA


Return to The Bridge: Discuss an Astronomy Picture of the Day

Who is online

Users browsing this forum: CommonCrawl [Bot], Easou [Spider] and 24 guests