Greenhouse Effect om Mars

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Extra Sense

PostPosted: June 15, 2005 10:48 AM 

The CO2 density on the surface of Mars is 30 times higher than that on Earth, as far as I know.

We are worried about our greenhouse effect, that supposedly increases temperatures, creating global warming.

Mars surface must be very hot, must not it?

e Razz s

Extra Nonsense

Posts: no

Reply: 1

PostPosted: June 15, 2005 10:55 AM 

Yes it must.

Extreme Nonsense

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Reply: 2

PostPosted: June 15, 2005 10:57 AM 


Profound Nonsense

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Reply: 3

PostPosted: June 15, 2005 11:02 AM 

Mars is Hell.

Extremely Profound Nonsense

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Reply: 4

PostPosted: June 15, 2005 11:07 AM 

Why do you think they call it the Red Planet?


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Reply: 5

PostPosted: June 16, 2005 2:18 AM 

FMR do some please.

They do not even accept a free atm place.

Spoof their IP please.

Doug Ellison

Posts: 1077

Reply: 6

PostPosted: June 16, 2005 4:38 AM 

Fav - what do you mean by 'spoof' ?


Extra Sense

Posts: 1471

Reply: 7

PostPosted: June 16, 2005 4:57 AM 


Do not get worked up too much, we need some humor here!

The main thing is that they agree with me

e Razz s

They're Rocks

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Reply: 8

PostPosted: June 16, 2005 11:47 AM 

Indeed, one hopes you are joking. I suspect all your posts are jokes, though I can't imagine what you get out of posting like this. In any event, it takes about a millionth of an attosecond to recognize the flaw in your OP, but in case you're serious, figure it out for yourself.

Extra Sense

Posts: 1471

Reply: 9

PostPosted: June 16, 2005 12:03 PM 


so you are pretending you know the answer, but would not tell anybody?

e Laughing s

They're Rocks

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Reply: 10

PostPosted: June 16, 2005 12:04 PM 

Just in case anyone is wondering:


They're Rocks

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Reply: 11

PostPosted: June 16, 2005 12:05 PM 

ES, have you ever been right about anything?

Extra Sense

Posts: 1471

Reply: 12

PostPosted: June 16, 2005 12:08 PM 

so this is where the dust you have in your head comes from! The site is deranged.
e Laughing s

Gingle Blingle Stoogleplex Frok Lorif Joiem Korknle

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Reply: 13

PostPosted: June 16, 2005 12:09 PM 

Extra Sense is perfectly right. The temperature on Mars is in excess of 700 degrees Celcius, it's just that all our measurements taken thus far show this not to be the case. Can't you see??????

Extra Sense

Posts: 1471

Reply: 14

PostPosted: June 16, 2005 12:12 PM 


You have clarified it, thanks

e Shocked s

They're Rocks

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Reply: 15

PostPosted: June 16, 2005 12:16 PM 

Well, you win, ES. The question now is, who will tell the NASA imbeciles?

They're Rocks

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Reply: 16

PostPosted: June 16, 2005 12:31 PM 

Conversation among NASA imbeciles:

"Bob, did you know that the surface temperature of Mars is hotter than Venus? It's that runaway greenhouse effect, you know."

"But, Jack, all our instruments say it's colder there than a nun in a brothel. Where are you getting this stuff?"

"From the Internet, at the Mars Blog. Extra Sense said so. It's because of the CO2 buildup."

"Well, damn my eyes! I guess it must be true then ... but, you know, the density of the Martian atmosphere is just one percent that of the earth's, so the higher proportion of CO2 as compared with the earth is utterly irrelevant. Moreover, a lot of CO2 is frozen and locked up in clouds and ice, because Mars is so, uh, cold... Oh, dear, my logic is getting all twisted in pretzels now!"

"Never mind all that, Bob. You're talking like a deranged man, now. To do real science, we must go to the Mars Blog and interact with the Extra Sense posting bot."

"Hoo hah! I see the light! Thanks, Jack!"

Martin Gradwell

Posts: 323

Reply: 17

PostPosted: June 16, 2005 12:46 PM 

Shame on you, TR, thinking something is true because a *web site* tells you so. You should know better by now.

"Composition of the Martian air is 95% Carbon Dioxide, 3% nitrogen and trace amounts of oxygen and water. The density of the Martian atmosphere is only 1% of Earth."

- I'll accept that much, because a *whole raft* of websites say the same thing, and it's numerical information which people can check up on and complain about if it's wrong.

On the other hand

"Mars density is so low that the carbon dioxide creates only a minor greenhouse effect"

is handwavy nonsense.

Even with all the CO2 we've been pouring into the atmosphere lately, CO2 is only about 370 parts per million of the Earth atmosphere. In terms of its contribution to atmospheric pressure, that's about 0.37 millibars. The pressure of CO2 on Mars is 95% of 10 millibars i.e. about 9.5 millibars. That's about 26 times as much as on Earth - pretty close to ES's figure of 30 times. The difference can be accounted for by him using some slightly different figures either for Mars atmospheric pressure or Earth CO2 levels.

On the face of it, there should be 26 times as much greenhouse effect due to CO2 on Mars as there is on Earth. And I am not aware of any non-handwavy argument which would suggest otherwise. The greenhouse effect is due to light hitting molecules of the greenhouse gas and being absorbed by them. The molecules then radiate heat in random directions, which means that something like 50% will be radiated downwards, increasing temperatures at lower heights. I do not see how this process could require a dense atmosphere, or how increasing the density of the Martian atmosphere by introducing only non-greenhouse gases could have a significant effect on the process.

The situation is complicated because the greenhouse effect is caused not only by CO2. Water vapour is probably the biggest contributor to the greenhouse effect on Earth, though it's difficult to quantify because the stuff gathers into clouds instead of spreading out evenly. Estimates of the proportion of the greenhouse effect due to water seem to vary wildly, from 30% to 88% (according to ) and it tends to get ignored because it isn't under human control to the same extent that CO2 emissions are. And there's methane and other greenhouse gases too that we could try to take into account, but none of this alters the fact that there should be a significant greenhouse effect on Mars.


Posts: 991

Reply: 18

PostPosted: June 16, 2005 1:31 PM 

I really don't think the greenhouse effect is significant at all on Mars. Even though its atmosphere is entirely composed of a "greenhouse gas", it still has a very very low density. But we don't need to guess at how well the atmosphere traps heat - they day night cycle already provides a way for us to measure that already.

On Mars, the temperature swings measured by Viking and Pathfinder ranged from 60 to 80 degrees C. On Venus, poster child of the Greenhouse Effect, the day and night sides don't show any appreciable difference in temperate at all!

They're Rocks

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Reply: 19

PostPosted: June 16, 2005 1:41 PM 

Martin, I realize you're an "against the mainstreamer" yourself, but in this case, you're demonstrably wrong. The thickness of the atmosphere certainly does matter, as do a lot of other factors, some of which you've pointed out (and distance from sun and albedo also matter). Here are a couple more links:

I suspect that the real thrust of ES's opening post was not to prove that Mars is actually hot (for that would truly be daft) but to try to discredit runaway greenhouse scenarios, by showing that even though we should have such a runaway on Mars, we don't. But the reason we don't is flat out because the atmosphere is way too thin -- the amount of carbon dioxide is irrelevant. However, even though Mars does not have a runaway greenhouse effect, it certainly does have some greenhouse effect, and without an atmosphere would be much colder than it actually is.

They're Rocks

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Reply: 20

PostPosted: June 16, 2005 1:57 PM 

To note further: even if the figure of 26X more CO2 in Mar's atmosphere is accurate, it's irrelevant, for two reasons: one, CO2 is not the only contributor to cause a runaway greenhouse, and (2) that CO2 on Mars is much more [i]attenuated[/i] than the greenhouse and non-greenhouse gasses on earth, and thus the percentage of heat that is scattered back to the Martian surface by it is correspondingly much lower. I'm sure some fairly rigorous maths could be worked out on this.

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