Mars "Ice"

Just saw an ALERT on Fox News (around 4:00PM - 6/20/08)) that according to NASA engineer Homer Hickan the Phoenix lander has found frozen water on Mars and it melted!



WOW,

Zip Monster

Saw this topic in todays papers myself, its a really nice find and apparently they have out ruled it to be anything but H2O Ice.


Edit: Thanks to Joe for reminding me where the edit button was.

/Fredrik Persson

i would suggest that Homer Hickman of NASA educate himself a bit more on chemical thermodynamics.

The atmosphere of Mars is about 1/100th the pressure of Earth. It is about 99% CO2. This means that the sublimation vapor ptressure of CO2 would be in equilibrium with the atmosphere at about -193 F. Since the coldest temperature at the north pole is listed as -220 F, and one might assume it is higher than -193 F during summertime, then the compound which would precipitate and vaporize over this temperature range is CO2. Since it is observed that the polar cap grows and shrinks from Winter to Summer, etc, this gross amount of material in the cap cannot be H2O. The level of H2O in the atmpsphere is only a trace level. The only reason exposed H2O ice would vaporize - under the influence of direct sunlight - is because it's presence in the atmosphere is only a trace level.

There is no discernable difference in the vapor pressure of water over the range of -220 F to -160 F. Since, in addition, it makes up "none" of the atmosphere, the growth of the polar cap cannot be attributed to H2O precipitation.

If this exposed "ice" rapidly vaporized over a period of several hours, this is inconsistent with the behavior of H2O ice at this temperature range.

Other evidence indicates substantial H2O exists on/in Mars, but I suspect that what was observed was the sublimation of "dry" ice.


Gregg Wilson

Gregg, interesting analysis. There is a bit more explanatory information in the article linked below. Apparently, it wasn't just a few hours:

"The key new evidence is that chunks of bright material exposed by digging on June 15 and still present on June 16 had vaporized by June 19..."

"the disappearing chunks could not have been carbon-dioxide ice at the local temperatures because that material would not have been stable for even one day as a solid."

[url] www.nasa.gov/mission_pages/phoenix/news/phoenix-20080620.html [/url]