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Fraser
2008-Jun-20, 01:10 PM
Phoenix scientists have been keeping an eye on the white material uncovered in a trench dug by the lander's scoop. Dice-size nuggets of the bright material have vanished, convincing scientists the material was frozen water that vaporized after digging exposed it. The image here is a "movie" showing the material disappearing after four [...]

More... (http://www.universetoday.com/2008/06/20/phoenix-it-must-be-ice/)

cope
2008-Jun-20, 03:31 PM
What eliminates frozen carbon dioxide as a possibility? I tried looking at phase diagrams but didn't get too far.

dhd40
2008-Jun-20, 04:33 PM
Phoenix scientists have been keeping an eye on the white material uncovered in a trench dug by the lander's scoop. Dice-size nuggets of the bright material have vanished, convincing scientists the material was frozen water that vaporized after digging exposed it. The image here is a "movie" showing the material disappearing after four [...]

More... (http://www.universetoday.com/2008/06/20/phoenix-it-must-be-ice/)

There are some surprising features in the "blinking" picture:
a) dark (non-white) particles that disappear as well
b) “white” particles (smaller ones) that show up while others (the bigger ones) disappear

This makes me wonder if the effects are generated by variations in the angle of illumination (as can be seen from the main shadow).
Which are the image numbers of the superimposed pictures (Sol 20 and 24)? Does anybody know?

ToSeek
2008-Jun-20, 06:46 PM
What eliminates frozen carbon dioxide as a possibility? I tried looking at phase diagrams but didn't get too far.

It's too warm at the landing site for it to be carbon dioxide.

KaiYeves
2008-Jun-20, 07:33 PM
Hurray! Go Phoenix, go Phoenix!