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| Methane instead of oxygen?; Inspired by Practically Uninformed's Tartarus | |
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| Topic Started: Feb 25 2010, 12:16 PM (616 Views) | |
| Rhob | Feb 25 2010, 12:16 PM Post #1 |
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Adult
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So I'm wondering about the likelihood that atmospheric methane could be abundant instead of atmospheric oxygen. What would be the trade-offs involved? Are there any clear disadvantages to metabolisms based on breathing methane? |
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| Pando | Feb 25 2010, 12:42 PM Post #2 |
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Obey or I'll send you to the moon
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Carbon has 12 atomic masses with 4 hydrogen, so it has 20 atomic masses. Oxygen has an atomic mass of 16, and there's 2 oxygen molecules in oxygen, so it has an atomic mass of 32. That would mean the gasses are almost half as light, although I don't know the effect that will have. Also, the whole photosynthesis and biological systems would have to be changed just to replace oxygen with methane. As a result everything will change from farther back, and we will have no idea how life be on land. But it would be different. I'm guessing though that the atmosphere will be thinner if the percentage of methane is the same as the percentage of oxygen in our Earth. So large flying pterosaurs would never of occurred, even if reptiles evolved. --Edit-- Methane also is 20X more effective at trapping heat than CO2, so you are looking at a very HOT world. Edited by Pando, Feb 25 2010, 12:46 PM.
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| Practically Uninformed | Feb 25 2010, 01:12 PM Post #3 |
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Informed enough to care
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Hm. I'd take it a temperate planet where life began in the atmosphere would definitely NOT have a methane-hydrogen system? |
| You may be a king or a lil' street sweeper, but sooner or later, you'll dance with the reaper! | |
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| Oceaniis | Feb 26 2010, 08:43 AM Post #4 |
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Adolescent
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I'm not sure if it's possible since methane is normaly a product of methabolism.... And if it's possible it wouldn't produce much energy ... pobably wouldn't support animal like organisms |
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| lamna | Feb 26 2010, 10:39 AM Post #5 |
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From what I know of chemistry methane would not be a very good replacement for oxygen at all. However it could produce cute little cannon fodder in the right circumstances. http://weremagnus.deviantart.com/art/Two-Little-Grunts-22531325 |
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Living Fossils Fósseis Vibos: Reserva Natural 34 MYH, 4 tonne dinosaur. [flash=500,450] Video Magic! [/flash] | |
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| Practically Uninformed | Feb 26 2010, 11:47 AM Post #6 |
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Informed enough to care
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Perhaps not methane, but some other sort of hydrocarbon? |
| You may be a king or a lil' street sweeper, but sooner or later, you'll dance with the reaper! | |
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| Ànraich | Mar 4 2010, 09:48 PM Post #7 |
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L'évolution Spéculative est moi
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As far as I know, there's nothing keeping life from using methane as it's gas-of-choice, but it would have to be the only choice. Otherwise the methane-life would quickly be ousted from existence by more efficient organisms, probably oxygen based. Perhaps on a world like Titan, where there is more methane than oxygen, life might use it. But if a world has oxygen then that's probably what life will end up using. |
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We should all aspire to die surrounded by our dearest friends. Just like Julius Caesar. "The Lord Universe said: 'The same fate I have given to all things from stones to stars, that one day they shall become naught but memories aloft upon the winds of time. From dust all was born, and to dust all shall return.' He then looked upon His greatest creation, life, and pitied them, for unlike stars and stones they would soon learn of this fate and despair in the futility of their own existence. And so the Lord Universe decided to give life two gifts to save them from this despair. The first of these gifts was the soul, that life might more readily accept their fate, and the second was fear, that they might in time learn to avoid it altogether." - Excerpt from a Chanagwan creation myth, Legends and Folklore of the Planet Ghar, collected and published by Yieju Bai'an, explorer from the Celestial Commonwealth of Qonming Tree That Owns Itself
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| Oceaniis | Mar 5 2010, 07:07 AM Post #8 |
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Adolescent
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Here's a breakdown of several different biochemistries that could create "life" A / Carbon based - with water for blood - who breathe oxygen - Earth like world B / Hydrocarbon based - ammonia for blood - who breathe hydrogen - lifeforms would develop on cold worlds in ammonia oceans, however technology as we know it wouldnt exist due to lack of fire. C / Carbon based - water for blood - who breathe chlorine - lifeforms would need additional ways to gather organic fuels due to chlorines inefficiency as a reagent compared to oxygen. D / Carbon based - sulfur dioxide for blood - who breathe sulfer trioxide - lifeforms would develop on cold worlds with lots of sulfur on the surface, lack of free oxygen though would prevent fires. E / Silicone based - sulfuric acid for blood - who breathe oxygen - lifeforms would develop on hot worlds. F / Flourosilicone based - sulfur as blood - who breathe sulfur dioxide - lifeforms would develop on even hotter worlds. |
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| T.Neo | Mar 5 2010, 08:43 AM Post #9 |
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Translunar injection: TLI
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Perhaps, in the place of fire, some other sort of exothermic reaction? Also, liquid isn't only used in blood... it's used everywhere. Inside cells, etc. As I've said before on these forums though, carbon + water is a pretty good combination. Both carbon and water seem to be the best chemicals for life, and they are abundant. Aqueous carbon based life is likely to be more common then "alternative" forms of life, even when including other possible environments for such "alternative" life. Edited by T.Neo, Mar 5 2010, 08:44 AM.
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| A hard mathematical figure provides a sort of enlightenment to one's understanding of an idea that is never matched by mere guesswork. | |
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| Rhob | Mar 5 2010, 04:55 PM Post #10 |
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Adult
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I'm not an expert in chemistry (let alone biochemistry), so I'm curious -- what makes methane so allegedly "inefficient" compared to oxygen? |
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| Oceaniis | Mar 6 2010, 12:17 PM Post #11 |
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Adolescent
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Oxygen is the most efficient gas... well nitrous oxide is better, but you don't have it in Nature
Yes, you understood what I meant. However there are problems in the formation of life, Amonia for example have a surface tension to be three times smaller than earth, and reducing its ability to concentrate non-polar molecules through a hydrophobic effect (first cells) and it's oxidizable and could not exist sustainably in a biosphere that oxidizes it ... Edited by Oceaniis, Mar 6 2010, 12:18 PM.
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| Moontanman | May 2 2010, 07:59 PM Post #12 |
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Zygote
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Plants could use methane, water and sunlight to make an oxidizer to store energy and give off hydrogen. Animals would breath in hydrogen and eat the stored oxidizers of plants and give off methane and water. The plant tissue would be rich in oxidizers and when lit would burn in hydrogen. This would be the opposite of what happens on the earth. On the earth sunlight is stored as carbohydrates and oxygen is given off. Both the carbohydrates and oxygen are ways the energy of sunlight is stored on the earth. Complex plants need oxygen the same as complex animals, on the earth plants store the energy of the sun as carbohydrates in their structure and store oxygen outside in the atmosphere. If you place a complex plant in a sealed container and give it plenty of light and CO2 and take away the oxygen faster than the plant can make it the plant will suffocate. Animals take advantage of this system by hijacking the carbohydrates of the plants and using the oxygen to gain energy, on the hypothetical planet due to an abundance of hydrogen this system would not work so the plants would have to store energy the opposite way and animals would still be able to take advantage of the plants storage systems. |
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