Freethought & Rationalism Archive

Kosh · 05-28-2002, 10:13 AM

I'm a little confused over some of the statements
made in the news articles regarding the ice
discovered underground on Mars.

They state that if the ice were to melt it would
flood the planet. Why? If the ice melted, wouldn't
it just stay in the ground as ground water? Ice
takes more volume than water. Also, they're claiming
this is where the oceans went. How can this
be? If there were vast oceans, then the ground
below them would have been saturated. NOt like the
water would have suddenly started soaking in, then
frozen.

Perhaps someone can enlighten me as to the physcial
forces they think are work here?

Thanks.

tronvillain · 05-28-2002, 11:01 AM

The water is probably of a lower density than the ground, so if it melted it might be forced towards the surface (imagine a tank with ice on the bottom and gravel on the top, now melt the ice).

Coragyps · 05-28-2002, 11:09 AM

I think that we have a case of an overenthusiastic journalist - I would bet that you are exactly right. The dusty surface of Mars is bound to have plenty enough porosity to hold lots of water, particularly as it has ice in those pores now. "If it were all melted, it could cover a Mars-sized billiard ball xx meters deep" is probably the accurate statement.
As to your oceans question - let me think on that a while.

B. H. Manners · 05-28-2002, 11:21 AM

If the water was to melt, would not the low atmospheric pressure cause the water to evaporate away?

Coragyps · 05-28-2002, 11:26 AM

Quote:

If the water was to melt, would not the low atmospheric pressure cause the water to evaporate away?

Yes, at the present pressure. Maybe we could start sending our excess greenhouse gases there to beef it up??

Asha'man · 05-28-2002, 05:54 PM

I also have a problem with that news report, but for another reason. The report that I saw said there was enough water to cover the planet 500m deep. However, the sensor that is detecting the Hydrogen is only good for a few meters deep.

If the polar areas (1/3 of the surface??) have that much water, it must be at least 1500m deep, which is much deeper than that instrument can detect.

Coragyps · 05-28-2002, 06:02 PM

I'll pirate all I can legally pirate from the actual paper when it comes out Friday..

Edited to add:

Till then, here's the <a href="http://science.nasa.gov/headlines/y2002/28may_marsice.htm?list8140" target="_blank">NASA press release.</a>

[ May 28, 2002: Message edited by: Coragyps ]</p>

05-28-2002, 10:13 AM	#1
Kosh Veteran Member Join Date: Apr 2001 Location: Orions Belt Posts: 3,911	Mars ice confusion... I'm a little confused over some of the statements made in the news articles regarding the ice discovered underground on Mars. They state that if the ice were to melt it would flood the planet. Why? If the ice melted, wouldn't it just stay in the ground as ground water? Ice takes more volume than water. Also, they're claiming this is where the oceans went. How can this be? If there were vast oceans, then the ground below them would have been saturated. NOt like the water would have suddenly started soaking in, then frozen. Perhaps someone can enlighten me as to the physcial forces they think are work here? Thanks.

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05-28-2002, 11:01 AM	#2
tronvillain Veteran Member Join Date: Oct 2000 Location: Alberta, Canada Posts: 5,658	The water is probably of a lower density than the ground, so if it melted it might be forced towards the surface (imagine a tank with ice on the bottom and gravel on the top, now melt the ice).

05-28-2002, 11:09 AM	#3
Coragyps Veteran Join Date: Aug 2001 Location: Snyder,Texas,USA Posts: 4,411	I think that we have a case of an overenthusiastic journalist - I would bet that you are exactly right. The dusty surface of Mars is bound to have plenty enough porosity to hold lots of water, particularly as it has ice in those pores now. "If it were all melted, it could cover a Mars-sized billiard ball xx meters deep" is probably the accurate statement. As to your oceans question - let me think on that a while.

05-28-2002, 11:21 AM	#4
B. H. Manners Veteran Member Join Date: Jan 2002 Location: Texas Posts: 1,213	If the water was to melt, would not the low atmospheric pressure cause the water to evaporate away?

05-28-2002, 05:54 PM	#6
Asha'man Veteran Member Join Date: Dec 2001 Location: southeast Posts: 2,526	I also have a problem with that news report, but for another reason. The report that I saw said there was enough water to cover the planet 500m deep. However, the sensor that is detecting the Hydrogen is only good for a few meters deep. If the polar areas (1/3 of the surface??) have that much water, it must be at least 1500m deep, which is much deeper than that instrument can detect.

05-28-2002, 06:02 PM	#7
Coragyps Veteran Join Date: Aug 2001 Location: Snyder,Texas,USA Posts: 4,411	I'll pirate all I can legally pirate from the actual paper when it comes out Friday.. Edited to add: Till then, here's the <a href="http://science.nasa.gov/headlines/y2002/28may_marsice.htm?list8140" target="_blank">NASA press release.</a> [ May 28, 2002: Message edited by: Coragyps ]</p>

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