Is There Water Ice on Mars?

[jim mcnamara]

http://www.itwire.com/content/view/18901/1066/
This just popped up. I guess more news services will have it shortly.

 

[robertm]

Here you go:

http://www.nasa.gov/mission_pages/phoenix/main/"

There will be a live telecom on the 20th. Pretty exciting! How great would it be if we found signs of life?!

 

[Gokul43201]

A bunch of white stuff that was seen at the bottom of a pit had disappeared 4 days later? How much more clear evidence do we need? What else can explain this but the existence of Martians?

 

[robertm]

I wasn't suggesting that the ice was evidence for life. We have know Mars to have water ice for ages. This is nothing new. But it is still exciting that we can now actually examine the ice.

 

[Ivan Seeking]

A bunch of white stuff that was seen at the bottom of a pit had disappeared 4 days later? How much more clear evidence do we need? What else can explain this but the existence of Martians?

One reporter suggested that the camera just wasn't working when the big green hand reached into the field of view. That seems to be the most likely explanation.

 

[B. Elliott]

I still don't understand all the hoopla about finding ice on Mars. I wouldn't be one bit suprised if we discovered ice... in fact I've been expecting it with 100% assurance.

What would be a good find, is if we discovered water ice.

 

[out of whack]

What would be a good find, is if we discovered water ice.

Big deal. Scotch on the rocks, now THAT would be reason to colonize.

 

[rewebster]

I got a feeling it will turn out to be dry ice (frozen co2) and the Earth (since the dirt on Earth is called 'earth', would the 'dirt' on Mars be called 'mars'?) acted as an insulator, and it just sublimated away.

 

[waht]

Phoenix lander is equipped with a mass spectrometer, and all sorts of instruments. It seems sort of premature to call that white stuff "ice" solely on relying on photographs as evidence, rather than other scientific instruments.

 

[Ivan Seeking]

Phoenix lander is equipped with a mass spectrometer, and all sorts of instruments. It seems sort of premature to call that white stuff "ice" solely on relying on photographs as evidence, rather than other scientific instruments.

What else would sublimate?

Isn't the real point that they will be able to study the ice - that they found some where they landed?

 

[edward]

Have they given a surface termperature range?? Does the sun shine on the area and for how long ect.??

 

[B. Elliott]

Have they given a surface termperature range?? Does the sun shine on the area and for how long ect.??

The sun shines constantly, but since it's in the process of dipping down past the horizon permanently during the winter season, the sunlight intensity is low. The temperature has been varying from about -30C to -80C. I haven't paid attention to pressure readings though. I also haven't heard of any speculation of what the ice may be, given the current data at hand.

 

[GeorginaS]

The sun shines constantly...

Ummm, yes? I haven't been around for that long, but I've been around for a while, and I haven't yet once heard of the sun going out. (Sorry, I couldn't resist.)

 

[rewebster]

I still think it's dry ice.

I'm thinking that "On Earth, as it is in the... (ooops) on Mars"---

Even in the summer, there's ice frozen a little ways under the ground near the Earth's poles (tundra)--on Mars it would be a 'dry ice' tundra----it's 'summer' where they are near the Mars 'pole'---so, I think it's 'dry ice tundra'.

 

[edward]

The sun shines constantly, but since it's in the process of dipping down past the horizon permanently during the winter season, the sunlight intensity is low. The temperature has been varying from about -30C to -80C. I haven't paid attention to pressure readings though. I also haven't heard of any speculation of what the ice may be, given the current data at hand.

Thanks for the information. Previous to the press release researchers at the U of A had noted the disappearance of the lumps in the lower left hand side of the pictures.

Someone there must have a sense of humor they have been giving things some pretty weird names. They referred to the lumps as "Dodo-Goldilocks"

http://phoenix.lpl.arizona.edu/

 

[Ivan Seeking]

I still think it's dry ice.

I'm thinking that "On Earth, as it is in the... (ooops) on Mars"---

Even in the summer, there's ice frozen a little ways under the ground near the Earth's poles (tundra)--on Mars it would be a 'dry ice' tundra----it's 'summer' where they are near the Mars 'pole'---so, I think it's 'dry ice tundra'.

It is believed that the Martian summers are too warm for it to be CO2.

 

[B. Elliott]

It is believed that the Martian summers are too warm for it to be CO2.

Isn't the line of thinking that the solid ice CO2 that's present at the poles during the winter months just evaporates and is redistributed into the atmosphere as gaseous CO2 during the warmer season(s)? I remember reading somewhere that approximately 25% of the detected CO2 is annually involved in this cycle.

Looking for the article now.

 

[rewebster]

It is believed that the Martian summers are too warm for it to be CO2.

on the surface, that may be true, but it may be different, --my guess, colder (like the tundra) a few inches down--cold enough to keep the dry ice as dry ice, and maybe even exposed, as it was, for a few days and longer than it would be expected (before it did sublimate, in the pit out of direct sunlight with colder ground below it).

________________________________-


I think the 'reason' why they 'think' its water is that they 'want' to see water so badly that they have thought of as many reasons WHY it should be water, instead looking at what's there already and thinking about what could be the reasons why it (co2) could be found below the surface (when it's not visible ON the surface).

 

[B. Elliott]

Roaring Jets of Carbon Dioxide Solve Mars Mystery

Peculiar spots, fan-like markings, and spider-shaped features on Mars' southern ice cap are seasonal formations, researchers announced today.

The shapes [see Images] are formed by thin layers of dark dusty material that are sprayed by roaring jets of carbon dioxide that erupt through the ice cap.

This dusty material may also be the reason that the southern ice cap doesn't reflect much light.

http://www.space.com/scienceastronomy/060816_mars_icecaps.html


This EGU article estimates as much as 1/2 of the surface CO2 is involved in the cycle...
http://www.cosis.net/abstracts/EGU2008/07999/EGU2008-A-07999.pdf?PHPSESSID=

 

[B. Elliott]

Thanks for the information. Previous to the press release researchers at the U of A had noted the disappearance of the lumps in the lower left hand side of the pictures.

Someone there must have a sense of humor they have been giving things some pretty weird names. They referred to the lumps as "Dodo-Goldilocks"

http://phoenix.lpl.arizona.edu/

Well, well, looks as though it can be H20...

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. "This tells us we've got water ice within reach of the arm, which means we can continue this investigation with the tools we brought with us," said Mark Lemmon of Texas A&M University, College Station, lead scientist for Phoenix's Surface Stereo Imager camera. He said 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.

http://phoenix.lpl.arizona.edu/06_20_pr.php

 

[rewebster]

The other 'thing' that bothers me about the 'chunks' is ---how did the 'chucks' form as 'chucks' in the first place?----would water form as 'chucks'?

Doesn't dry ice form in 'chunks'? Water would seem to go from a liquid state to a frozen aggregate in and of the material that it would be in the liquid state (like frozen dirt). CO2 forms as a semi-crystal from the vapor, doesn't it?--and would appear as a chunk?



"He said 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."

It's below the surface and touches colder ground below it, that changes the parameters.

 

[B. Elliott]

Something that is neat, is that the conditions around Phoenix hover right around the borderline between H20s solid and gas phase...

the average pressure was 8.55 millibars

http://phoenix.lpl.arizona.edu/05_27_pr.php

~8.55 millibars = 855 pascals

-30ºC = 243K
-80ºC = 193K

I wish I could find more data on the pressure variation.

 

[rewebster]

do they have one of those charts for co2?




hmmm- I wonder if those 'waterfalls' (on the sides of the cliffs on Mars), then, are some form of that very small possibility realm of some sort of outpouring of a CO2 'waterfall'?

 

[B. Elliott]

Took a minute to find one with the same scales so it's easier to read.

Can't find one with pascals instead of atmospheres.

 

[B. Elliott]

Strange. Google says 855 pascals = 0.00843819393 atmospheres. So, going by that last chart, there shouldn't be any solid CO2 at all in the area? In fact the pressure is waaay off from being close. I'm guessing exposed CO2 would evaporate immediately?

 

[rewebster]

http://hypertextbook.com/facts/2000/LaurenMikulski.shtml

"The pressure of Mars's atmosphere varies with the season, ranging from 6 to 10 millibars (1 millibar is approximately one one-thousandth of the air pressure at the surface of Earth)."

well, the temps are right in the 'right' areas for CO2 to sublimate and crystalize most of the time maybe at the 'poles' and become liquid at Mars's temps too (maybe in the equitorial and 'temperate' zones

"The average recorded temperature on Mars is -63 °C (-81 °F) with a maximum temperature of 20 °C (68 °F) and a minimum of -140 °C (-220 °F)."

http://hypertextbook.com/facts/2001/AlbertEydelman.shtml

 

[rewebster]

Strange. Google says 855 pascals = 0.00843819393 atmospheres. So, going by that last chart, there shouldn't be any solid CO2 at all in the area? In fact the pressure is waaay off from being close. I'm guessing exposed CO2 would evaporate immediately?

"minimum of -140 °C"


dry ice stays in a cooler for quite a while (on Earth)--maybe it stays longer below Earth (Mars earth/dirt, that is)

 

[B. Elliott]

"minimum of -140 °C"dry ice stays in a cooler for quite a while (on Earth)--maybe it stays longer below Earth (Mars earth/dirt, that is)

True, but I'm wondering how the temperatures vary across the surface as a whole; latitudinal night/day differences along with with varying elevations (pressures/temps). While also taking into consideration the difference between temperature and heat... heating effects by the sun during the daytime.

So much to consider!

 

[rewebster]

True, but I'm wondering how the temperatures vary across the surface as a whole; latitudinal night/day differences along with with varying elevations (pressures/temps). While also taking into consideration the difference between temperature and heat... heating effects by the sun during the daytime.

So much to consider!

ahhhh---that's I still think its dry ice (for all the above reasons)

 

[B. Elliott]

Here's the kind of charts I've been looking for...

http://www-k12.atmos.washington.edu/k12/resources/mars_data-information/temperature_overview.html

 

[rewebster]

yeah--but those are ave. temps----you'd have to know the temp and pressure (and the atmospheric concentration of co2) where the thing landed (and the temp of the ground a couple inches down)

 

[B. Elliott]

yeah--but those are ave. temps----you'd have to know the temp and pressure (and the atmospheric concentration of co2) where the thing landed (and the temp of the ground a couple inches down)

Well, you do have to consider the average temps as they change seasonally. That, and I doubt there's drastic changes CO2 movement over a period of just a few hours, or even days. It gives the latitude in the link... 47.2 slightly lower than the Phoenix.

 

[Alienjoey]

Ah, this isn't the first time we've found water on Mars!
http://apod.nasa.gov/apod/ap050401.html

This is certainly an interesting discovery, and evidence is pointing to the likelihood that it really is water!

 

[rewebster]

I think there is water on Mars, but I still don't think those white chunks were (are) water.


You know what would really be funny (funny in the way of the discovery) would be that all those 'water' features (the valleys, dry river beds, etc.) were caused by liquid CO2 instead of liquid water. If all the circumstances were just right (like on Earth for the glaciers to create those 'U' shaped valleys, all those river beds on Mars could have been created by liquid CO2.

 

[B. Elliott]

I think there is water on Mars, but I still don't think those white chunks were (are) water. You know what would really be funny (funny in the way of the discovery) would be that all those 'water' features (the valleys, dry river beds, etc.) were caused by liquid CO2 instead of liquid water. If all the circumstances were just right (like on Earth for the glaciers to create those 'U' shaped valleys, all those river beds on Mars could have been created by liquid CO2.

I think that's been one of the theories so far since Mars atmosphere is over 95% CO2. Allow the atmosphere to be saturated with enough CO2, and you'll have CO2 condensation. And if the atmosphere was actually thick enough, you'd have the pressure available for it ran down as a liquid and flow.

 

[rewebster]

I think that's been one of the theories so far since Mars atmosphere is over 95% CO2. Allow the atmosphere to be saturated with enough CO2, and you'll have CO2 condensation. And if the atmosphere was actually thick enough, you'd have the pressure available for it ran down as a liquid and flow.

I hadn't heard of it before--I'll look around- ...or if anyone else can find it first.

 

[B. Elliott]

Excellent article...

http://www.spacedaily.com/news/mars-water-science-00k1.html

 

[rewebster]

Excellent article...

http://www.spacedaily.com/news/mars-water-science-00k1.html

thanks---good theory---a good 'find', there, B. Elliott ---

-he keeps saying that the valleys weren't caused by 'liquid'--however, I think that there will still be a way for liquid CO2 to flow there--maybe still mixed with that h2o that he mentions. Some of those valleys are (seem) just too much like a 'fluid' erosion, and not a "density flow". Maybe a variation of his idea of underground 'pressure'.

"These flows are part of a suite of "Density Flows", so named because they consist of a dense fluidised cloud that flows downhill as if it were a fluid."

http://www.spacedaily.com/news/mars-water-science-00k2.html

 

[Gokul43201]

I think there is water on Mars, but I still don't think those white chunks were (are) water.


You know what would really be funny (funny in the way of the discovery) would be that all those 'water' features (the valleys, dry river beds, etc.) were caused by liquid CO2 instead of liquid water. If all the circumstances were just right (like on Earth for the glaciers to create those 'U' shaped valleys, all those river beds on Mars could have been created by liquid CO2.

I believe thay have ruled out dry ice:

We can easily and confidently rule out that its carbon dioxide ice," said Lemmon. "There are certainly times of the year that there would be CO2 ice at this location but with the temperatures we are measuring there, it would be the equivalent of water ice existing on Earth at 140 degrees. It wouldn't be there very long, and wouldn't be there long enough for us to take its picture, and it wouldn't last the night. We're very confident this is not CO2 ice.

http://www.universetoday.com/2008/0...ference-update-proof-of-water-ice/#more-15217

 

[rewebster]

I think all they have to do is stick a thermometer down into the 'chunks' the next time they make a trench----

betcha it's dry ice (like a dry ice tundra)


I think the 'surface' temps are probably a whole lot different than even just a couple of inches down on Mars at/near the poles (less direct sun, just like here on Earth). E.g.---how far down is 'frozen tundra' on Earth when its 70-80 degrees F on the surface? --and Mars has a whole lot less atmosphere to aid in the warming of the 'dirt', too.


I wonder how warm the core of Mars is?

 

[jqnsmart]

I think we can definitely rule out carbon dioxide. Mars' atmosphere has a pressure of 0.007 times that of Earth, or 0.007 atm or 700 Pa. At this pressure, carbon dioxide could be solid only at extremely low temperature, close to absolute zero. Even if it could survive underground as ice, it would sublimate almost instantly when coming in contact with the Martian atmosphere.

Water, can exist as ice, because its triple point is at 0.006 atm (almost the pressure of Mars' atmosphere) and about 0 degrees Celsius. This would allow water to sublimate if the temperature rose enough.

This is where I got my info on water and carbon dioxide (I got the atmospheric pressure on Mars from a book):

http://www.uiowa.edu/~c004131a/Phase_Diagrams.html

 

[rewebster]

Today:

"After weeks of testing the soil in the Martian arctic, NASA's Phoenix lander has confirmed through chemical analysis the presence of water on another planet, scientists revealed today."


"The fact that it melted at 0 degrees centigrade leaves very little doubt," said Boynton, speaking at a news conference in Tucson"

http://www.latimes.com/news/science/la-sci-phoenix1-2008aug01,0,3012423.story


"Laboratory tests aboard NASA's Phoenix Mars Lander have identified water in a soil sample. The lander's robotic arm delivered the sample Wednesday to an instrument that identifies vapors produced by the heating of samples."

http://www.nasa.gov/mission_pages/phoenix/news/phoenix-20080731.html

so...it is water

I think we can definitely rule out carbon dioxide. Mars' atmosphere has a pressure of 0.007 times that of Earth, or 0.007 atm or 700 Pa. At this pressure, carbon dioxide could be solid only at extremely low temperature, close to absolute zero. Even if it could survive underground as ice, it would sublimate almost instantly when coming in contact with the Martian atmosphere.

Water, can exist as ice, because its triple point is at 0.006 atm (almost the pressure of Mars' atmosphere) and about 0 degrees Celsius. This would allow water to sublimate if the temperature rose enough.

This is where I got my info on water and carbon dioxide (I got the atmospheric pressure on Mars from a book):

http://www.uiowa.edu/~c004131a/Phase_Diagrams.html

but there are carbon dioxide polar caps not too far away

 

[jqnsmart]

Sorry it has taken me so long to respond, but I had a problem with my internet company that lasted quite some time. I do, however, feel an obligation to respond. Even thought the polar ice caps are nearby, any carbon dioxide exposed would sublimate almost instantly, especially since it was summer then. In fact the ice caps sublimate in the summer and reform in the winter.