Water Ice Confirmed!, White stuff sublimates away Options

[ugordan]

Here's a flicker between sol 21 and 24 showing change (or, rather, lack of):


Ignore the color of the brightest part of the white stuff, it's overexposed. The small white chunk in sol 21 image appears to disappear in sol 24 (inset).

[akuo]

Ignore the color of the brightest part of the white stuff, it's overexposed. The small white chunk in sol 21 image appears to disappear in sol 24 (inset).

Are you referring to the chunk that appeared on sol 19 and the was smeared into smaller bits on sol 20? Hard to say in the shadow, but those chunks may have indeed disappeared.

[ugordan]

Yes, that one. It's in the shadow in sol 24 image, but other darker bits are subtly visible and yet this one isn't.

[Juramike]

Nice animation!

There is another tiny chunk in the far right of the images (below the furthest right white streak) that is in full sunlight in both images that went away in the second image of the sequence.

-Mike

[Tomek]

The small white chunk in sol 21 image appears to disappear in sol 24 (inset).

yes exactly
hortonheardawho from marsroverblog.com found this for sure now .

IT is ice

http://www.flickr.com/photos/hortonheardaw...881091/sizes/o/

[slinted]

Here's my take on the sol 20 - sol 24 changes using the 5 filter (R1ABC2) set from each for comparison. Ugordon's warnings about the brightest features absolutely apply. There might be legitimate changes, but they might also just be overexposure / time-of-day / stretching differences.

The "bright stuff" under the shadow I feel much more confident about: it's there on sol 20, gone by sol 24.

[Tomek]

good point to obserwation is in this place also



http://www.flickr.com/photos/hortonheardaw...881091/sizes/o/

[fredk]

Beautiful stuff, guys. I agree about the disappearing light bits in the shadow. But the lighting in the latest gifs (slinted, horton) is very similar on sols 20 and 24, as you can see by the shadows. We are again clearly seeing a darkening over time of the larger exposed substrate areas.

How does this sound: White substrate is mostly white ice, plus some dark dust/sand impurities. As the ice sublimates, the impurities are left behind. Eventually, the surface of the substrate is essentially completely covered by the dark impurities. That stage has almost been reached on the leftmost large exposed substrate area - there's very little white left by sol 24.

[elakdawalla]

Awesome animation, slinted. That went straight to the blog.

--Emily

[belleraphon1]

slinted and all...

awesome indeed ... Peter Smith agrees...

http://phoenix.lpl.arizona.edu/06_19_pr.php

MUST BE ICE!!!!

Craig

[mars loon]

http://phoenix.lpl.arizona.edu/06_19_pr.php
MUST BE ICE!!!!

"It must be ice," said Phoenix Principal Investigator Peter Smith of the University of Arizona, Tucson. "These little clumps completely disappearing over the course of a few days, that is perfect evidence that it's ice. There had been some question whether the bright material was salt. Salt can't do that."

There is also an animation at the UA Phoenix page clearly showing the changes at lower left of Dodo-Goldilocks. Images from Sols 20 and 24 (June 15 and 18, 2008). "These images show sublimation of ice in the trench informally called "Dodo-Goldilocks" over the course of four days".


Pay Dirt !!

ken

[fredk]

So as far as those disappearing chunks, how did they sublimate so fast? I thought we were talking microns per day of sublimation...

[Reed]

That was for ice attached to a large body. A relatively small piece sitting on regolith would behave quite differently.

It also crosses my mind that those "chunks" might be more like shavings than solid blocks.

[Juramike]

I so could not resist this!

Ice, Ice Baby!



EDIT: poignant lyric for today:
"If there was a problem yo I'll solve it
Check out the hook while my DJ revolves it "

[stewjack]

Media Update

NASA and the University of Arizona, Tucson, will hold a media teleconference at 10 a.m. PDT (1 p.m. EDT) (5 p.m. UTC) on Friday, June 20, to report on the latest news from NASA's Phoenix Mars Lander mission.

I wonder what the major topic will be?

Jack

Note This conference is only posted on the Arizona web page as of 11:00 p.m. EDT. I hope it will be announced on NASA's audio streaming page soon

Streaming Page
http://www.nasa.gov/news/media/newsaudio/index.htm