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koraks
Registered: 06/02/03
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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: imachavel]
#20795261 - 11/05/14 02:49 AM (9 years, 3 months ago) |
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Quote:
imachavel said: "One of the major, although less publicized, discoveries from Cassini is that there are very, very large molecules at the top of Titan’s atmosphere. These molecules are something like 1,000 times bigger than methane and are located at around 950 km altitude in Titan’s atmosphere (a bit farther than driving from LA to Vegas and back). "
http://www.planetary.org/blogs/guest-blogs/2013/0515-doing-a-science-on-titan.html
That's pretty interesting, although it's not clear what kind of molecules these exactly are. But the pathway that's explained, UV breaking multiple bonds allowing the atoms or smaller molecules to recombine into larger ones sounds pretty logical to me.
Quote:
But after showing you a wiki article claiming methane has been disproven to form abiogenically, you continue to explain that it is formed abiogenically.
Can you please explain the process by which it is formed abiogenically? I need the education. Thank you
There are probably several routes, but one that comes to mind is the Sabatier process, in which CO2 and H2 are combined into methane and water. Further reactions that can be grouped under the Fischer-Tropsch label can convert the methane into longer organic molecules, effectively creating abiogenic oil. These processes are the probable cause of abiogenic organic compounds we find on earth in deep-ocean settings near volcanic vents and it's not unlikely that similar processes could play a role in the origins of the methane found on Titan. By the way, the origins of that methane may be very well not on Titan itself, as NASA has put forth the hypothesis that this methane could have become part of Titan as the moon was formed and therefore could have originated somewhere else, so the current conditions on Titan are not even a limitation in understanding the formation of its possibly (and I'd say: highly probable) abiogenic methane.
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imachavel
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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: koraks]
#20795637 - 11/05/14 07:57 AM (9 years, 3 months ago) |
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Perhaps you are wrong, perhaps you are right 100%. I certainly don't know. In fact the only thing that is 100% fact is no one knows as of yet:
"The Mystery of Methane on Mars and Titan It might mean life, it might mean unusual geologic activity; whichever it is, the presence of methane in the atmospheres of Mars and Titan is one of the most tantalizing puzzles in our solar system"
From:
http://www.scientificamerican.com/article/methane-on-mars-titan/
I hope one day its existence is a proven fact and not just several hypothesis and inconclusive theory.
Thank you for the discussion.
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imachavel
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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: imachavel]
#20795678 - 11/05/14 08:23 AM (9 years, 3 months ago) |
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I feel this is probably the most extensive explanation I've heard so far:
"Split by Sunlight The first step to answering the question is to determine the rate at which methane must be produced or delivered. That, in turn, depends on how fast the gas is being removed from the atmosphere. At altitudes of 60 kilometers and higher above the Martian surface, solar ultraviolet radiation splits methane molecules apart. Lower in the atmosphere, oxygen atoms and hydroxyl radicals (OH), which form when water molecules are broken apart by ultraviolet photons, oxidize methane. Without being resupplied, methane would gradually disappear from the atmosphere. The “lifetime” of methane—defined as the time it takes for the gas concentration to drop by a factor of the mathematical constant e, or roughly three—is 300 to 600 years, depending on the amount of water vapor, which undergoes seasonal changes, and on the strength of solar radiation, which varies during the solar cycle. On Earth, similar processes give methane a lifetime of about 10 years. On Titan, where solar ultraviolet radiation is much weaker and oxygen-bearing molecules are substantially less abundant, methane can last 10 million to 100 million years (which is still a short time in geologic terms). Methane’s lifetime on Mars is long enough for winds and diffusion to mix the gas into the atmosphere fairly uniformly. Thus, the observed variations of methane levels over the planet are puzzling. They may be a sign that the gas comes from localized sources or disappears into localized sinks. One possible sink is chemically reactive soil, which could accelerate the loss of methane. If such additional sinks operated, it would take an even larger source to maintain the observed abundance. The next step is to consider potential scenarios for forming methane. The Red Planet is a good place to start because its methane abundance is so low. If a mechanism cannot explain even this small amount, it would be unlikely to account for Titan’s much greater quantity. For a 600-year lifetime, a little over 100 metric tons of methane would have to be produced each year to maintain a constant global average of 10 ppbv. That is about a quarter-millionth the production rate on Earth. As on Earth, volcanoes are most likely not responsible. Martian volcanoes have been extinct for hundreds of millions of years. Furthermore, if a volcano had been responsible for the methane, it would also have pumped out enormous quantities of sulfur dioxide, and Mars’s atmosphere is devoid of sulfur compounds. Extraplanetary contributions also appear minimal. Some 2,000 tons of micrometeoritic dust are estimated to reach the Martian surface every year. Less than 1 percent of their mass is carbon, and even this material is largely oxidized and hence an insignificant source of methane. Comets are about 1 percent methane by weight, but they strike Mars only once every 60 million years on average. Thus, the amount of methane delivered would be about one ton a year, or less than 1 percent of the required amount. Could it be that a comet struck Mars in the recent past? It could have delivered a large amount of methane, and over time the abundance in the atmosphere would have declined to its present value. An impact of a comet 200 meters in diameter 100 years ago, or a comet 500 meters in diameter 2,000 years ago, could have supplied sufficient methane to account for the currently observed global average value of 10 ppbv. But this idea runs into a problem: the distribution of methane is not uniform over the planet. The time it takes to distribute methane uniformly vertically and horizontally is at most several months. Thus, a cometary source would result in a uniform methane distribution over Mars, contrary to observations. Smoke in the Waters That leaves us with two possible sources: hydrogeochemical and microbial. Either one would be fascinating. Hydrothermal vents, known as black smokers, were first discovered on Earth in 1977 on the Galápagos Rift [see “The Crest of the East Pacific Rise,” by Ken C. Macdonald and Bruce P. Luyendyk; Scientific American, May 1981]. Since then, oceanographers have found them along many other midoceanic ridges. Laboratory experiments show that under the conditions prevailing at these vents, ultramafic silicates—rocks rich in iron or magnesium, such as olivine and pyroxene—can react to produce hydrogen in a process commonly referred to as serpentinization. In turn, reaction of hydrogen with carbon grains, carbon dioxide, carbon monoxide or carbonaceous minerals can produce methane. The keys to this process are hydrogen, carbon, metals (which act as catalysts), and heat and pressure. All are available on Mars, too. The process of serpentinization can occur either at high temperatures (350 to 400 degrees C) or at milder ones (30 to 90 degrees C). These lower temperatures are estimated to occur within purported aquifers on Mars. Although low-temperature serpentinization may be capable of producing the Martian methane, biology remains a serious possibility. On Earth, microorganisms known as methanogens produce methane as a by-product of consuming hydrogen, carbon dioxide or carbon monoxide. If such organisms lived on Mars, they would find a ready supply of nutrients: hydrogen (either produced in the serpentinization process or diffusing into the soil from the atmosphere) plus carbon dioxide and carbon monoxide (in the rocks or from the atmosphere). Once formed by either serpentinization or microbes, methane could be stored as a stable clathrate hydrate—a chemical structure that traps methane molecules like animals in a cage—for later release to the atmosphere, perhaps by gradual outgassing through cracks and fissures or by episodic bursts triggered by volcanism. No one is sure how efficiently the clathrates would form or how readily they would be destabilized. The Mars Express observations hint at greater methane concentrations over areas containing subsurface water ice. Either the geologic or biological scenario would explain this correlation. Aquifers below the ice would provide a habitat for creatures or a venue for the hydrogeochemical production of methane. Without more data, the biological and geologic possibilities appear equally likely. A Titanic Ocean At first glance, one might think that Titan’s methane would be easier to understand: the moon formed in the subnebula of Saturn, whose atmosphere contains huge amounts of the gas. Yet the data argue for production of methane on Titan rather than delivery of methane to Titan. The Huygens probe of the joint NASA and European Space Agency’s Cassini-Huygens Mission found no xenon or krypton in the moon’s atmosphere. Had the planetesimals that formed Titan brought methane, they would have brought these heavy noble gases as well. The absence of such gases indicates that methane most likely formed on Titan. Therefore, the presence of methane on Titan is as mysterious as it is on Mars—in some respects more so because of its sheer quantity (5 percent by volume). A plausible source, as on Mars, is serpentinization at relatively low temperatures. Christophe Sotin of the University of Nantes in France and his colleagues have argued that Titan might sustain an underground ocean of liquid water. Dissolved ammonia, acting as an antifreeze, would help to keep it from freezing solid. In their model, the ocean is 100 kilometers underneath Titan’s surface and 300 to 400 kilometers deep. In the past, the decay of radioactive elements and the leftover heat from Titan’s formation might have melted nearly all the body’s ice—so the ocean might have extended all the way down to the rocky core. Under those conditions, reactions between the water and the rock would have liberated hydrogen gas, which in turn would have reacted with carbon dioxide, carbon monoxide, carbon grains or other carbonaceous material—producing methane. I estimate that this process would have been capable of explaining Titan’s observed methane abundance. Once produced, methane could have been stored as a stable clathrate hydrate and released to the atmosphere either gradually, through volcanism, or in bursts, triggered by impacts. An intriguing clue is the argon 40 gas detected by Huygens as it descended through Titan’s atmosphere. This isotope forms by the radioactive decay of potassium 40, which is sequestered in the rocks deep in Titan’s core. Because the radioactive half-life of potassium 40 is 1.3 billion years, the small amount of argon 40 in the atmosphere is evidence for slow release of gases from the interior. In addition, optical and radar images of the surface show signs of cryovolcanism—geyserlike eruptions of ammonia-water ice—which also indicates that material wells up from the interior. The surface appears relatively young and free of craters, which is a sign of resurfacing by material from the interior. The estimated resurfacing rate would release methane from the interior quickly enough to balance the photochemical loss. Methane on Titan plays the role of water on Earth, complete with liquid surface reservoirs, clouds and rain—a full-fledged methalogical cycle. Thus, a substantial body of evidence exists, even more so than for Mars, that methane stored in the interior would have no difficulty getting out to the surface and subsequently evaporating into the atmosphere. Might biology also play a role in creating Titan’s methane? Christopher McKay of the NASA Ames Research Center and Heather Smith of the International Space University in Strasbourg, France, as well as Dirk Schulze-Makuch of Washington State University and David Grinspoon of the Denver Museum of Nature and Science, have suggested that acetylene and hydrogen could serve as nutrients for methanogens even in the extreme cold of Titan’s surface (–179 degrees C). This biogenic process differs from that employed by methanogens on Earth and their cousins, if any, on Mars in that no water is needed. Instead liquid hydrocarbons on Titan’s surface serve as the medium. Yet this hypothesis has a shortcoming. Huygens data rule out an underground source of acetylene; this compound must ultimately come from methane in the atmosphere. Thus, it seems like a circular argument: to produce methane (by microbes), one needs methane. Moreover, the sheer abundance of methane on Titan is so immense that methanogens would have to work in overdrive to produce it, severely depleting the available nutrients. In view of these obstacles, a biological explanation for methane is much less attractive on Titan than on Mars. Nevertheless, the hypothesis of habitability bears investigating. Some scientists argue that this moon might have been or still be habitable. It receives enough sunlight to turn nitrogen and methane into molecules that are the precursors to biology. An underground water-ammonia brine, with some methane and other hydrocarbons thrown in, could be a friendly environment for complex molecules or even living organisms. In the distant past, when the young Titan was still cooling off, liquid water may even have flowed on the surface."
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Herbologist
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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: imachavel]
#20795713 - 11/05/14 08:33 AM (9 years, 3 months ago) |
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has anyone seen this? glimmers of light shining of bodies of water on Titan.
http://www.iflscience.com/space/titans-polar-seas-glint-sunlight
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imachavel
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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: Herbologist]
#20796161 - 11/05/14 10:53 AM (9 years, 3 months ago) |
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That is freaking awesome. That has got to be one of the most beautiful things I've ever seen. I personally love these types of photos:

I wish there tons of super high res photos of Titan etc. I think it'll be amazing one day, it'll probably be long after I'm gone, when some type of astronaut program can put people on the surface of Titan, in some sort of suit that resist the density. If the density on the surface is 1.5 times our earth density, it should be easy, considering the type of pressure multiplied that a bathosphere can endure
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Mushrumours
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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: imachavel]
#20859074 - 11/19/14 06:05 AM (9 years, 2 months ago) |
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Apparently there was a big debate on weather or not NASA would rule Titan to be believed to once be inhabited by life. But there was no organic material found on or in the surface . No organic material to NASA means no life ever there as far as the ruling for now.
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imachavel
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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: Mushrumours]
#20859768 - 11/19/14 10:59 AM (9 years, 2 months ago) |
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They haven't drastically explored under the surface in the first place.
Which is where they think the source of the methane is. Its very possible much warmer conditions in which life could survive is under the surface.
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Razzldazzle

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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: imachavel]
#20888422 - 11/25/14 12:30 PM (9 years, 2 months ago) |
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Just because there is methane on titan does not prove life exists. Everything in our solar system is carbon based, hence we are carbon-based lifeforms. Europa, another moon orbiting Jupiter is a frozen orb of ice. Ice floats in water but its too far from the sun to contain liquid water. The gravity of Jupiter may be expanding and compressing the core of Europa, causing friction and maybe enough heat to melt the ice between the ice-crust and the core, creating a vast ocean beneath the icy crust. So I think Europa would have a much higher probability of containing simple lifeforms on it than Titan.
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LostHippie165
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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: Razzldazzle]
#20934740 - 12/05/14 07:56 PM (9 years, 2 months ago) |
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Yea I find it kind of silly that we are wondering where all this methane comes from on Titan....because its all over the solar system (and in the interstellar medium, where material is too sparsely distributed to support life as we know it).
Venus contains large amounts of methane in the lowest 35 miles of its atmosphere.
Mercury's thin atmosphere contains trace amounts of methane (even though it is bathed in high energy UV all of the time), and Earths Moon offgasses trace amounts of methane on a regular basis.
Other moons of Saturn and Uranus contain higher atmospheric methane content than Titan, and methane makes up significant portions of surface ice on some of Uranus's moons.
http://en.wikipedia.org/wiki/List_of_interstellar_and_circumstellar_molecules#Four_atoms_.2826.29 Hydrocarbons (including methane), and several chemical precursors used in the industrial production of methane (NaoH, H20, Acetic Acid, etc.) have all been identified as components of interstellar medium. This suggests that the bulk of methane and precursors to abiogenic methane production were around before/during/after solar/planetary formation. The higher concentrations of methane in the outer planets seem to support this theory (lighter gases are more difficult to gravitationally constrain closer to the sun, and thus are blown outward to form the gas giants.
I will admit that nobody knows for sure, which is why space exploration funding is so important....
Cheers, LostHippie165
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Visionary Tools



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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: ShootinD5nukes]
#20974331 - 12/14/14 08:44 AM (9 years, 2 months ago) |
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Methane is a very simple substance, 4 atoms of hydrogen, 1 of carbon. You squeeze those two together at high pressure and heat (like say, in the Mohorovicic discontinuity boundary) and you get methane, non-organic, abiogenic origin.
Unfortunately, it's not a well known bit of chemistry, so yeah, I could see where you're coming from.
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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: Visionary Tools]
#21286856 - 02/17/15 08:43 AM (9 years, 22 hours ago) |
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NASA planning a possible mission to Titan.
Building a submarine to navigate the Kraken Ocean through liquid methane.
http://www.iflscience.com/space/check-out-nasa-s-conceptual-submarine-explore-titan-s-kraken-mare
Quote:
 Saturn is orbited by 62 official moons, the largest of which is Titan. However, Titan is not your average satellite - larger than the planet Mercury, Titan has a thick nitrogen atmosphere and a large liquid hydrocarbon lakes on the surface. Unfortunately, it has been difficult to obtain much information about the lakes’ depth or composition from the orbital missions. NASA has recently revealed what a conceptual submarine mission to Kraken Mare, the largest sea on Titan, would look like. Kraken Mare contains enough liquid methane to fill Lake Michigan three times over. Conditions are presumed to be rough, with changing tides and massive waves.
The hypothetical submarine would travel about 2,000 kilometers (1,250 miles) over the course of a 90 day mission. While the craft wouldn’t have a problem staying under the sea during that time and diving, it will need to surface in order to transmit data back to Earth. It would be powered by a radioisotope thermoelectric generator which doesn’t have moving parts, making it a good choice for a craft with such a long journey and will be dropped into the sea. Most of the power will be used to propel the submarine while under the surface, but will be capable of performing science missions as well.
During the mission, the submarine would make a number of observations and collect data using a variety of instruments. Some of the main objectives would be to analyze the chemical composition of the liquid, but also other oceanographic features such as currents and tidal patterns. The craft would also be equipped with cameras in order to image Titan’s shoreline and landscape. The science goals are pretty vague at such an early juncture, but would be more refined and detailed if the mission planning continues.
It is unknown when such a mission would ever take place, as this is really just the first rough draft of what could be used to explore Titan’s Kraken Mare with a submarine. There are a number of technological and logistical obstacles to address before any proposed launch dates are developed, including Titan’s orbit around Saturn. It takes nearly 30 Earth years for Titan to revolve around the planet, which will influence when such a mission could take place.
Other proposed missions to explore Titan’s seas include the Titan Mare Explorer (TiME) mission proposed in 2009, which functions more like a buoy than a boat. Unfortunately, the mission has been scrapped due to lack of development of the proposed fuel source. However, a similar mission would likely precede an extensive submarine mission, as is proposed here:
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Le_Canard
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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: imachavel]
#21291813 - 02/18/15 02:34 AM (9 years, 4 hours ago) |
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It is exciting, but the jury is still out on there being life on Titan. This definitely needs to be checked out.
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Herbologist
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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: Le_Canard]
#21292806 - 02/18/15 10:08 AM (8 years, 11 months ago) |
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I just really really want to believe that there is other forms of life out there.
Can you imagine if that submarine is navigating an ocean on Titan when suddenly something swims by? Then the submarine detects a bump against the side?
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Re: forgive me if I'm in the dark about this, but the idea of life on Titan has already been proven righ [Re: Herbologist]
#21296670 - 02/19/15 01:27 AM (8 years, 11 months ago) |
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Well sure, me too. And I love the idea of the submarine. This definitely needs more investigation.
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