Timeline for Why is Mars cold?
Current License: CC BY-SA 4.0
16 events
| when toggle format | what | by | license | comment | |
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| Oct 14, 2019 at 19:20 | comment | added | Jack R. Woods | While we are talking percentages, Venus has as much or maybe more nitrogen than Earth. It is just a low percentage compared to the CO2 abundance. | |
| Oct 11, 2019 at 14:48 | vote | accept | CommunityBot | ||
| Oct 11, 2019 at 14:46 | comment | added | user30617 | Thank you very much for the answer! | |
| Oct 11, 2019 at 13:33 | comment | added | pela | @jamesqf It would be roughly 5 K colder, which is the difference between Mars' effective temperature and its average surface temperature. For Earth, that difference is 33 K (see my answer below for references). | |
| Oct 11, 2019 at 5:54 | comment | added | Luaan | @jamesqf Probably almost exactly the same. The radiative forcing from carbon dioxide is tiny, and quickly drops off (e.g. the difference between 100 ppm and 200 ppm is much larger than between 1000 ppm and 1100 ppm). Water vapour and methane are much more important, but on a planet like Mars, water vapour would be "quickly" lost. On Earth, more carbon dioxide also lets the air to hold more water vapour, which also lets more carbon dioxide into the atmosphere, which is a bit of a positive feedback loop. But geologically speaking, carbon dioxide on its own essentially doesn't matter. | |
| Oct 10, 2019 at 16:40 | comment | added | jamesqf | @pela: So what would the temperature of Mars be if it had no atmosphere, or if the atmosphere was composed entirely of non-greenhouse gasses like nitrogen or argon? | |
| Oct 9, 2019 at 15:28 | comment | added | PM 2Ring | @uhoh Good idea. | |
| Oct 9, 2019 at 15:25 | comment | added | uhoh | I made a small edit, I missed the water part the first time through as well, since you led with absolute pressure, then went on to CO2. | |
| Oct 9, 2019 at 15:24 | history | edited | uhoh | CC BY-SA 4.0 |
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| Oct 9, 2019 at 13:08 | comment | added | pela | Good thing I'm not an observer :D | |
| Oct 9, 2019 at 12:54 | comment | added | PM 2Ring | @pela <cue joke about blind astronomer> :) | |
| Oct 9, 2019 at 12:41 | comment | added | pela | Ah okay, I only saw that now. | |
| Oct 9, 2019 at 12:17 | history | edited | PM 2Ring | CC BY-SA 4.0 |
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| Oct 9, 2019 at 12:16 | comment | added | PM 2Ring | @pela True, and that's why I added that info about water. But I suppose I shouldn't make that a "BTW" section. | |
| Oct 9, 2019 at 12:12 | comment | added | pela | But Earth's atmosphere only has 0.04% CO$_2$, so that's an order of magnitude less than Mars, in absolute values. | |
| Oct 9, 2019 at 12:10 | history | answered | PM 2Ring | CC BY-SA 4.0 |