Methane by zzzmarcus

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									From Wikipedia, the free encyclopedia

Methane

Methane
Methane NFPA 704

4 1 0 Flash point -188 °C

Related compounds Related Alkanes Ethane, propane Related compounds Methanol, chloromethane, formic acid, formaldehyde, silane n, εr, etc.

Other names Identifiers CAS number PubChem SMILES

Methyl hydride, Marsh gas, firedamp [74-82-8] 297
C

Supplementary data page Structure and properties

Thermodynamic Phase behaviour data Solid, liquid, gas Spectral data UV, IR, NMR, MS

InChI
1/CH4/h1H4

Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references

ChemSpider ID Properties Molecular formula Molar mass Appearance Density Melting point Boiling point Solubility in water Hazards MSDS R-phrases S-phrases

291 CH4 16.042 g/mol Colorless gas 0.717 kg/m3, gas 415 kg/m3 liquid -182.5 °C, 91 K, -297 °F -161.6 °C, 112 K, -259 °F 3.5 mg/100 mL (17 °C)

External MSDS R12 (S2), S9, S16, S33

Methane is a chemical compound with the molecular formula CH4. It is the simplest alkane, and the principal component of natural gas. Methane’s bond angles are 109.5 degrees. Burning methane in the presence of oxygen produces carbon dioxide and water. The relative abundance of methane and its clean burning process makes it a very attractive fuel. However, because it is a gas at normal temperature and pressure, methane is difficult to transport from its source. In its natural gas form, it is generally transported in bulk by pipeline or LNG carriers; few countries still transport it by truck. Methane was discovered and isolated by Alessandro Volta between 1776 and 1778 when studying marsh gas from Lake Maggiore. Methane is a relatively potent greenhouse gas with a high global warming potential of 72 (averaged over 20 years) or 25 (averaged

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over 100 years).[1] Methane in the atmosphere is eventually oxidized, producing carbon dioxide and water. As a result, methane in the atmosphere has a half life of seven years. The abundance of methane in the Earth’s atmosphere in 1998 was 1745 parts per billion, up from 700 ppb in 1750. In the same time period, CO2 increased from 278 to 365 parts per million. The radiative forcing effect due to this increase in methane abundance is about one-third of that of the CO2 increase.[2] In addition, there is a large, but unknown, amount of methane in methane clathrates in the ocean floors. The Earth’s crust contains huge amounts of methane. Large amounts of methane are produced anaerobically by methanogenesis. Other sources include mud volcanoes, which are connected with deep geological faults, and livestock (primarily cows) from enteric fermentation. Methane is a significant contributor to global warming and the Kyoto protocol seeks to regulate its production.

Methane
methane off-gas can penetrate the buildings’ interiors and expose occupants to significant levels of methane. Some buildings have specially engineered recovery systems below their basements to actively capture such fugitive off-gas and vent it away from the building. An example of this type of system is in the Dakin Building, Brisbane, California.

Reactions of methane
Main reactions with methane are: combustion, steam reforming to syngas, and halogenation. In general, methane reactions are hard to control. Partial oxidation to methanol, for example, is difficult to achieve; the reaction typically progresses all the way to carbon dioxide and water.

Combustion
In the combustion of methane, several steps are involved: Methane is believed to form a formaldehyde (HCHO or H2CO). The formaldehyde gives a formyl radical (HCO), which then forms carbon monoxide (CO). The process is called oxidative pyrolysis: CH4 + O2 → CO + H2 + H2O Following oxidative pyrolysis, the H2 oxidizes, forming H2O, replenishing the active species, and releasing heat. This occurs very quickly, usually in significantly less than a millisecond. 2H2 + O2 →2H2O Finally, the CO oxidizes, forming CO2 and releasing more heat. This process is generally slower than the other chemical steps, and typically requires a few to several milliseconds to occur. 2CO + O2 →2CO2 The result of the above is the following total equation: CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) + 890 kJ/mol[3] where bracketed "g" stands for gaseous form and bracketed "l" stands for liquid form.

Properties
Methane is the major component of natural gas, about 87% by volume. At room temperature and standard pressure, methane is a colorless, odorless gas; the smell characteristic of natural gas as used in homes is an artificial safety measure caused by the addition of an odorant, often methanethiol or ethanethiol. Methane has a boiling point of −161 °C at a pressure of one atmosphere. As a gas it is flammable only over a narrow range of concentrations (5–15%) in air. Liquid methane does not burn unless subjected to high pressure (normally 4–5 atmospheres).

Potential health effects
Methane is not toxic; however, it is highly flammable and may form explosive mixtures with air. Methane is violently reactive with oxidizers, halogens, and some halogen-containing compounds. Methane is also an asphyxiant and may displace oxygen in an enclosed space. Asphyxia may result if the oxygen concentration is reduced to below 19.5% by displacement. The concentrations at which flammable or explosive mixtures form are much lower than the concentration at which asphyxiation risk is significant. When structures are built on or near landfills,

Hydrogen activation
The strength of the carbon-hydrogen covalent bond in methane is among the strongest in all hydrocarbons, and thus its use as a chemical feedstock is limited. Despite the high activation barrier for breaking the C–H bond, CH4 is still the principal starting material for manufacture of hydrogen in steam reforming. The search for catalysts which can

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facilitate C–H bond activation in methane and other low alkanes is an area of research with considerable industrial significance.

Methane
Methane in the form of compressed natural gas is used as a vehicle fuel, and is claimed to be more environmentally friendly than other fossil fuels such as gasoline/petrol and diesel. Research is being conducted by NASA on methane’s potential as a rocket fuel. One advantage of methane is that it is abundant in many parts of the solar system and it could potentially be harvested in situ , providing fuel for a return journey.[4] Current methane engines in development produce a thrust of 7,500 pounds , which is far from the seven million pounds needed to launch the space shuttle. Instead, such engines will most likely propel voyages from our moon or send robotic expeditions to other planets in the solar system.[5] Recently methane emitted from coal mines has been successfully converted to electricity.[6]

Reactions with halogens
Methane reacts with all halogens given appropriate conditions, as follows: CH4 + X2 → CH3X + HX where X is a halogen: fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). This mechanism for this process is called free radical halogenation. When X is Cl, this mechanism has the following form: 1. Radical generation:

• The needed energy comes from UV radiation or heating, 2. Radical exchanges:

3. Radical extermination:\!

Industrial uses
Methane is used in industrial chemical processes and may be transported as a refrigerated liquid (liquefied natural gas, or LNG). While leaks from a refrigerated liquid container are initially heavier than air due to the increased density of the cold gas, the gas at ambient temperature is lighter than air. Gas pipelines distribute large amounts of natural gas, of which methane is the principal component. In the chemical industry, methane is the feedstock of choice for the production of hydrogen, methanol, acetic acid, and acetic anhydride. When used to produce any of these chemicals, methane is first converted to synthesis gas, a mixture of carbon monoxide and hydrogen, by steam reforming. In this process, methane and steam react on a nickel catalyst at high temperatures (700–1100 °C).

• If methane and X2 are used in equimolar quantities, CH2X2, CHX3, and even CX4 are formed. Using a large overquantitity of CH4 reduces the production of CH2X2, CHX3, CX4, and thus more CH3X is formed.

Uses
Fuel
Methane is important for electrical generation by burning it as a fuel in a gas turbine or steam boiler. Compared to other hydrocarbon fuels, burning methane produces less carbon dioxide for each unit of heat released. At about 891 kJ/mol, methane’s combustion heat is lower than any other hydrocarbon; but a ratio with the molecular mass (16.0 g/mol) divided by the heat of combustion (891 kJ/mol) shows that methane, being the simplest hydrocarbon, produces more heat per mass unit than other complex hydrocarbons. In many cities, methane is piped into homes for domestic heating and cooking purposes. In this context it is usually known as natural gas, and is considered to have an energy content of 39 megajoules per cubic meter, or 1,000 BTU per standard cubic foot.

The ratio of carbon monoxide to hydrogen in synthesis gas can then be adjusted via the water gas shift reaction to the appropriate value for the intended purpose. CO + H2O → CO2 + H2 Less significant methane-derived chemicals include acetylene, prepared by passing methane through an electric arc, and the chloromethanes (chloromethane, dichloromethane, chloroform, and carbon tetrachloride), produced by reacting methane with chlorine gas.

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However, the use of these chemicals is declining. Acetylene is replaced by less costly substitutes, and the use of chloromethanes is diminishing due to health and environmental concerns.

Methane
a method of recovering methane from an unminable coal seam. Scientific experiments have given variable results in determining whether plants are a source of methane emissions.[12][13][14]

Sources of methane
Natural gas fields
The major source of methane is extraction from geological deposits known as natural gas fields. It is associated with other hydrocarbon fuels and sometimes accompanied by helium and nitrogen. The gas at shallow levels (low pressure) is formed by anaerobic decay of organic matter and reworked methane from deep under the Earth’s surface. In general, sediments buried deeper and at higher temperatures than those which give oil generate natural gas. Methane is also produced in considerable quantities from the decaying organic wastes of solid waste landfills.

Methane in Earth’s atmosphere

Alternative sources
Apart from gas fields, an alternative method of obtaining methane is via biogas generated by the fermentation of organic matter including manure, wastewater sludge, municipal solid waste (including landfills), or any other biodegradable feedstock, under anaerobic conditions. Methane hydrates/clathrates (icelike combinations of methane and water on the sea floor, found in vast quantities) are a potential future source of methane. Cattle belch methane accounts for 16% of the world’s annual methane emissions to the atmosphere.[7] The livestock sector in general (primarily cattle, chickens, and pigs) produces 37% of all human-induced methane".[8] However animals "that put their energies into making gas are less efficient at producing milk and meat". Early research has found a number of medical treatments and dietary adjustments that help limit the production of methane in ruminants.[9][10][11] Industrially, methane can be created from common atmospheric gases and hydrogen (produced, for example, by electrolysis) through chemical reactions such as the Sabatier process, Fischer-Tropsch process. Coal bed methane extraction is a method for extracting methane from a coal deposit, while enhanced coal bed methane recovery is

Methane concentrations graph

Computer models showing the amount of methane (parts per million by volume) at the surface (top) and in the stratosphere (bottom). Early in the Earth’s history—about 3.5 billion years ago—there was 1,000 times as much methane in the atmosphere as there is now.

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Methane
decreased. The average mole concentration of methane at the Earth’s surface in 1998 was 1,745 ppb.[15] Its concentration is higher in the northern hemisphere as most sources (both natural and human) are larger. The concentrations vary seasonally with a minimum in the late summer mainly due to removal by the hydroxyl radical. Methane is created near the surface, and it is carried into the stratosphere by rising air in the tropics. Uncontrolled build-up of methane in Earth’s atmosphere is naturally checked—although human influence can upset this natural regulation—by methane’s reaction with hydroxyl radicals formed from singlet oxygen atoms and with water vapor.

Methane as a greenhouse gas
Methane in the Earth’s atmosphere is an important greenhouse gas with a global warming potential of 25 kg CO2 over a 100-year period. This means that a methane emission will have 21 times the impact on temperature of a carbon dioxide emission of the same mass over the following 100 years. Methane has a large effect for a brief period (a net lifetime of 8.4 years in the atmosphere), whereas carbon dioxide has a small effect for a long period (over 100 years). Because of this difference in effect and time period, the global warming potential of methane over a 20 year time period is 72. The Earth’s methane concentration has increased by about 150% since 1750, and it accounts for 20% of the total radiative forcing from all of the longlived and globally mixed greenhouse gases.[16] Usually, excess methane from landfills and other natural producers of methane are burned so CO2 is released into the atmosphere instead of methane because methane is such a more effective greenhouse gas. Recently methane emitted from coal mines has been successfully converted to electricity. Megtec Systems Inc. developed a patented combination of emission control and steam cycle technologies, the VOCSIDIZER which has been converting the energy of the coal mine’s 0.9% VAM concentration into electrical power.[17]

Global average methane concentrations from measurement (NOAA)

Methane levels (green curve) in 420,000 years of ice core data from Vostok, Antarctica research station. Current period is at left The earliest methane was released into the atmosphere by volcanic activity. During this time, Earth’s earliest life appeared. These first, ancient bacteria added to the methane concentration by converting hydrogen and carbon dioxide into methane and water. Oxygen did not become a major part of the atmosphere until photosynthetic organisms evolved later in Earth’s history. With no oxygen, methane stayed in the atmosphere longer and at higher concentrations than it does today. In present times, due to the increase in oxygen, the amount of methane has

Emissions accounting of methane
The balance between sources and sinks is not yet fully understood. The IPCC Working Group 1 stated in chapter 2 of the Fourth

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Origin Natural Emissions Wetlands (incl. Rice agriculture) Termites Ocean Hydrates Natural Total Anthropogenic Emissions Energy Landfills Ruminants (Livestock) Waste treatment Biomass burning Anthropogenic Total Sinks Soils Tropospheric OH Stratospheric loss Sink Total Emissions + Sinks Imbalance (trend) +20 ~2.78 Tg/ppb -30 -510 -40 -580 -5 -88 -7 -100 -5 -85 -7 -97 110 40 115 25 40 330 33 12 35 8 12 100 18 7 19 4 7 55 225 20 15 10 270 83 7 6 4 100 37 3 3 2 45 CH4 Emission Mass (Tg/a) Type (%/a)

Methane

Total (%/a)

+7.19 ppb/a

Assessment Report that there are "large uncertainties in the current bottom-up estimates of components of the global source", and the balance between sources and sinks is not yet well known. The most important sink in the methane cycle is reaction with the hydroxyl radical, which is produced photochemically in the atmosphere. Production of this radical is not fully understood and has a large affect on atmospheric concentrations. This uncertainty is exemplified by observations that have shown between the year 2000 and 2006 increases in atmospheric concentration of methane ceased without reduction in anthropogenic sources, showing that methane accounting does not accurately predict methane observations. Houweling et al. (1999) give the following values for methane emissions (Tg/a=teragrams per year):[15] Slightly over half of the total emission is due to human activity.[16] Living plants (e.g. forests) have recently been identified as a potentially important source of methane. A 2006 paper calculated

emissions of 62–236 Tg a-1, and "this newly identified source may have important implications".[18][19] However the authors stress "our findings are preliminary with regard to the methane emission strength".[20] These findings have been called into question in a 2007 paper which found "there is no evidence for substantial aerobic methane emission by terrestrial plants, maximally 0.3% of the previously published values".[21] Long term atmospheric measurements of methane by NOAA show that the build up of methane has slowed dramatically over the last decade, after nearly tripling since pre-industrial times.[22] It is thought that this reduction is due to reduced industrial emissions and drought in wetland areas. Very recent data now suggests that methane concentrations may be rising again.[23]

Removal processes
The major removal mechanism of methane from the atmosphere involves radical chemistry; it reacts with the hydroxyl radical

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(·OH), initially formed from water vapor broken down by oxygen atoms that come from the cleavage of ozone by ultraviolet radiation: CH4 + ·OH → ·CH3 + H2O This reaction in the troposphere gives a methane lifetime of 9.6 years. Two more minor sinks are soil sinks (160 year lifetime) and stratospheric loss by reaction with ·OH, ·Cl and ·O1D in the stratosphere (120 year lifetime), giving a net lifetime of 8.4 years.[15] Oxidation of methane is the main source of water vapor in the upper stratosphere (beginning at pressure levels around 10 kPa). The methyl radical formed in the above reaction will, during normal daytime conditions in the troposphere, usually react with another hydroxyl radical to form formaldehyde. Note that this is not strictly oxidative pyrolysis as described previously. Formaldehyde can react again with a hydroxyl radical to form carbon dioxide and more water vapor. Note that sidechains in these reactions may interact with nitrogen compounds that will likely produce ozone, thus supplanting radicals required in the initial reaction.[24]

Methane

Release of methane from bogs
Although less dramatic than release from clathrates, but already happening, is an increase in the release of methane from bogs as permafrost melts. Although records of permafrost are limited, recent years (1999 to 2007) have seen record thawing of permafrost in Alaska and Siberia. Recent measurements in Siberia show that the methane released is five times greater than previously estimated.[25]

Extraterrestrial methane
Methane has been detected or is believed to exist in several locations of the solar system. It is believed to have been created by abiotic processes, with the possible exception of Mars. • Moon - traces are present in the thin atmosphere[26] • Mars - the atmosphere contains 10 ppb methane. In January 2009, NASA scientists announced that they had discovered that the planet regularly vents methane into the atmosphere in specific areas at regular times, leading some to speculate this may be a sign of biological activity going on below the surface.[27] • Jupiter - the atmosphere contains about 0.3% methane • Saturn - the atmosphere contains about 0.4% methane • Iapetus • Titan — the atmosphere contains 1.6% methane[28] • Enceladus - the atmosphere contains 1.7% methane[29] • Uranus - the atmosphere contains 2.3% methane • Ariel - methane is believed to be a constituent of Ariel’s surface ice • Miranda • Oberon - about 20% of Oberon’s surface ice is composed of methanerelated carbon/nitrogen compounds • Titania - about 20% of Titania’s surface ice is composed of methane-related organic compounds • Umbriel - methane is a constituent of Umbriel’s surface ice • Neptune - the atmosphere contains 1.6% methane

Sudden release from methane clathrates
See also: Arctic methane release and Clathrate gun effect At high pressures, such as are found on the bottom of the ocean, methane forms a solid clathrate with water, known as methane hydrate. An unknown, but possibly very large quantity of methane is trapped in this form in ocean sediments. The sudden release of large volumes of methane from such sediments into the atmosphere has been suggested as a possible cause for rapid global warming events in the Earth’s distant past, such as the Paleocene–Eocene Thermal Maximum of 55 million years ago, and the Great Dying. Theories suggest that should global warming cause them to heat up sufficiently, all of this methane could again be suddenly released into the atmosphere. Since methane is twenty-five times stronger (for a given weight, averaged over 100 years) than CO2 as a greenhouse gas; this would immensely magnify the greenhouse effect, heating Earth to unprecedented levels (see Clathrate gun hypothesis).

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From Wikipedia, the free encyclopedia
• Triton - Triton has a tenuous nitrogen atmosphere with small amounts of methane near the surface.[30][31] Pluto - spectroscopic analysis of Pluto’s surface reveals it to contain traces of methane[32][33] • Charon - methane is believed to be present on Charon, but it is not completely confirmed[34] Eris - infrared light from the object revealed the presence of methane ice Comet Halley Comet Hyakutake - terrestrial observations found ethane and methane in the comet[35] Extrasolar planet HD 189733b - This is the first detection of an organic compound on planets outside the solar system. It is unknown how it originated, when the high temperature (700°C) favors the formation of carbon monoxide instead.[36] Interstellar clouds[37]

Methane
climate/ipcc_tar/wg1/221.htm. Retrieved on 2008-05-26. [3] SCHAUM’S OUTLINE SERIES, ORGANIC CHEMISTRY [4] http://science.nasa.gov/headlines/y2007/ 04may_methaneblast.htm?list123532 [5] Green, V. (2007) Hit the Gas: NASA’s methane rocket could make long distance space travel possible, on the cheap. Popular Science magazine, September. pg 16-17. [6] A Global First: Coal Mine Turns Greenhouse Gas into Green Energy [7] Miller, G. Tyler. Sustaining the Earth: An Integrated Approach. U.S.A.: Thomson Advantage Books, 2007. 160. [8] "Livestock’s Long Shadow–Environmental Issues and Options". http://www.virtualcentre.org/ en/library/key_pub/longshad/ A0701E00.htm. Retrieved on 2007-01-04. [9] California Cows Fail Latest Emissions Test [10] New Zealand Tries to Cap Gaseous Sheep Burps [11] Research on use of bacteria from the stomach lining of kangaroos (who don’t emit methane) to reduce methane in cattle [12] Hamilton JT, McRoberts WC, Keppler F, Kalin RM, Harper DB (July 2003). "Chloride methylation by plant pectin: an efficient environmentally significant process". Science (journal) 301 (5630): 206–9. doi:10.1126/science.1085036. PMID 12855805. http://www.sciencemag.org/cgi/ pmidlookup?view=long&pmid=12855805. [13] "Methane Emissions? Don’t Blame Plants", ScienceNOW, 14 January 2009 [14] Plants do emit methane after all, New Scientist, 2 December 2007 [15] ^ "Trace Gases: Current Observations, Trends, and Budgets". Climate Change 2001. United Nations Environment Programme. http://www.grida.no/ climate/ipcc_tar/wg1/134.htm#4211. [16] ^ "Technical summary". Climate Change 2001. United Nations Environment Programme. http://www.grida.no/ climate/ipcc_tar/wg1/017.htm. [17] "A Global First: Coal Mine Turns Greenhouse Gas into Green Energy". MEGTEC Systems Inc.. MEGTEC

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See also
• • • • • • • • • • • • • • 2007 Zasyadko mine disaster Abiogenic petroleum origin Anaerobic digestion Anaerobic respiration Biogas Coal Oil Point seep field Greenhouse gas Halomethane, halogenated methane derivatives. List of alkanes Methanation Methane clathrate, form of water ice which contains methane. Methanogen, archaea that produce methane as a metabolic by-product. Methanogenesis, the formation of methane by microbes. Methanotroph, bacteria that are able to grow using methane as their only source of carbon and energy. Methyl group, a functional group similar to methane. Organic gas Thomas Gold

• • •

References
[1] IPCC Fourth Assessment Report [2] "Radiative Forces of Climate Change". Climate Change 2001: The Scientific Basis. IPCC. http://www.grida.no/

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Systems. http://www.megtec.com/ news_article.php?news_id=42. [18] "Methane emissions from terrestrial plants under aerobic conditions". Nature. 2006-01-12. http://www.nature.com/ nature/journal/v439/n7073/abs/ nature04420.html. Retrieved on 2006-09-07. [19] "Plants revealed as methane source". BBC. 2006-01-11. http://news.bbc.co.uk/ 2/hi/science/nature/4604332.stm. Retrieved on 2006-09-07. [20] "Global warming - the blame is not with the plants". eurekalert.org. 2006-01-18. http://www.eurekalert.org/pub_releases/ 2006-01/m-gw-011806.php. Retrieved on 2006-09-06. [21] Duek, Tom A.; Ries de Visser, Hendrik Poorter, Stefan Persijn, Antonie Gorissen, Willem de Visser, Ad Schapendonk, Jan Verhagen, Jan Snel, Frans J. M. Harren, Anthony K. Y. Ngai, Francel Verstappen, Harro Bouwmeester, Laurentius A. C. J. Voesenek, Adrie van der Werf (2007-03-30). "No evidence for substantial aerobic methane emission by terrestrial plants: a 13C-labelling approach.". New Phytologist (Blackwell) 175: 29. doi:10.1111/ j.1469-8137.2007.02103.x. http://www.blackwell-synergy.com/doi/ abs/10.1111/j.1469-8137.2007.02103.x. Retrieved on 2007-04-23. [22] "SCIENTISTS PINPOINT CAUSE OF SLOWING METHANE EMISSIONS". NOAA news Online. http://www.noaanews.noaa.gov/ stories2006/s2709.htm. Retrieved on 2007-05-23. [23] "Annual Greenhouse Gas Index (AGGI) Indicates Sharp Rise in Carbon Dioxide and Methane in 2007=NOAA news Online". http://www.esrl.noaa.gov/news/ 2008/aggi.html. Retrieved on 2008-06-16. [24] "Methane and Carbon Monoxide in the Troposphere". http://www.atmosp.physics.utoronto.ca/ people/loic/chemistry.html. Retrieved on 2008-07-18. [25] "Methane bubbles climate trouble". BBC. 2006-09-07. http://news.bbc.co.uk/2/hi/ science/nature/5321046.stm. Retrieved on 2006-09-07.

Methane
[26] Stern, S.A. (1999). "The Lunar atmosphere: History, status, current problems, and context". Rev. Geophys. 37: 453–491. doi:10.1029/ 1999RG900005. [27] http://www.washingtonpost.com/wp-dyn/ content/article/2009/01/15/ AR2009011502222.html [28] H. B. Niemann, et al. (2005). "The abundances of constituents of Titan’s atmosphere from the GCMS instrument on the Huygens probe". Nature 438: 779–784. doi:10.1038/nature04122. [29] Waite, J. H.; et al.; (2006); Cassini Ion and Neutral Mass Spectrometer: Enceladus Plume Composition and Structure, Science, Vol. 311, No. 5766, pp. 1419–1422 [30] A L Broadfoot, S K Bertaux, J E Dessler et al. (December 15, 1989). "Ultraviolet Spectrometer Observations of Neptune and Triton". Science 246: 1459–1466. doi:10.1126/science.246.4936.1459. PMID 17756000. http://adsabs.harvard.edu/abs/ 1989Sci...246.1459B. Retrieved on 2008-01-15. [31] Ron Miller; William K. Hartmann (May 2005). The Grand Tour: A Traveler’s Guide to the Solar System (3rd ed.). Thailand: Workman Publishing. pp. 172–73. ISBN 0-7611-3547-2. [32] Tobias C. Owen, Ted L. Roush et al. (6 August 1993). "Surface Ices and the Atmospheric Composition of Pluto". Science 261 (5122): 745–748. doi:10.1126/science.261.5122.745. PMID 17757212. http://www.sciencemag.org/ cgi/content/abstract/261/5122/745. Retrieved on 2007-03-29. [33] "Pluto". SolStation. 2006. http://www.solstation.com/stars/ pluto.htm. Retrieved on 2007-03-28. [34] B. Sicardy et al. (2006). "Charon’s size and an upper limit on its atmosphere from a stellar occultation". Nature 439: 52. doi:10.1038/nature04351. http://www.nature.com/nature/journal/ v439/n7072/abs/nature04351.html. [35] Mumma, M.J.; Disanti, M.A., dello Russo, N., Fomenkova, M., Magee-Sauer, K., Kaminski, C.D., and D.X. Xie (1996). "Detection of Abundant Ethane and Methane, Along with Carbon Monoxide and Water, in Comet C/1996 B2 Hyakutake: Evidence for Interstellar

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Origin". Science 272: 1310. doi:10.1126/ science.272.5266.1310. http://adsabs.harvard.edu/cgi-bin/nphbib_query?bibcode=1996Sci...272.1310M. [36] Stephen Battersby (2008-02-11). "Organic molecules found on alien world for first time". http://space.newscientist.com/article/ dn13303-organic-molecules-found-onalien-world-for-first-time.html. Retrieved on 2008-02-12. [37] J. H. Lacy, J. S. Carr, N. J. Evans, II, F. Baas, J. M. Achtermann, J. F. Arens (1991). "Discovery of interstellar methane - Observations of gaseous and solid CH4 absorption toward young stars in molecular clouds". Astrophysical Journal 376: 556–560. doi:10.1086/ 170304. http://adsabs.harvard.edu/abs/ 1991ApJ...376..556L.

Methane

External links
• Gavin Schmidt, Methane: A Scientific Journey from Obscurity to Climate SuperStardom, NASA Goddard, September 2004 • Methane thermodynamics • Methane in tundra and oceans to be released in atmosphere • International Chemical Safety Card 0291 • Methane Hydrates • Computational Chemistry Wiki • Safety data for methane • Dynamic Viscosity of Methane • Thermal Conductivity of Methane • METHANE-EATING BUG HOLDS PROMISE FOR CUTTING GREENHOUSE GAS. Media Release, GNS Science, New Zealand] • Catalytic conversion of methane to more useful chemicals and fuels

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