As the Cassini orbiter makes its 103rd close pass by Titan, have long-agers found ways to keep it billions of years old?Space.com announced the 103rd flyby of Titan by Cassini, and it’s a daring one: just 2,274 miles above the surface at 13,000 miles per hour; PhysOrg announced the next day that it was successful. With about 40% of the surface mapped by radar and other instruments, enough should be known by now to explain its youthful appearance in terms of the assumed age of the solar system (4.5 billion years).Astrobiology Magazine reported that JPL chemists are getting closer to reproducing Titan’s peculiar smog, but the fit isn’t perfect yet. That article did not address the age conundrum: how long can Titan’s atmosphere create these complex molecules, and are they reversible?Jeff Hecht at New Scientist was the only reporter recently to address the age question. First, he laid out the problem:Scientists have puzzled over Titan’s atmospheric methane because sunlight causes the molecule to react readily with other chemicals in the air, producing the moon’s dense smog. Calculations suggest that the amount of methane now found in Titan’s atmosphere should have been used up within tens of millions of years – a blip in the moon’s roughly 4-billion-year lifetime….Adding to the mystery, the methane reactions create hydrocarbon compounds that rain over the surface. If fresh methane emissions steadily replaced used-up methane over the course of Titan’s history, this process would happen constantly, and Titan would be covered not by lakes, but by a global ocean hundreds of metres deep.Such an ocean, of course, was not found, sending theoreticians scrambling for answers. Hecht’s favorite answer is the snowball cycle proposed by Caltech’s Michael Wong. Periodically, the atmosphere collapses, then reappears. This happens because the methane provides only a marginal greenhouse effect to keep the nitrogen in a gas phase. In the cycle scenario, the methane gets used up, the nitrogen freezes out, and the atmosphere turns to ice on the surface – until enough new methane outgasses to warm it up again. There are several “if’s” in this scenario:Methane levels may rise and fall if the gas is periodically released from inside the moon, which would explain how Titan has so much in its atmosphere today. If at some point the methane dropped by a factor of 100, temperatures would fall, and surface liquids would ice over. The haze produced by methane reactions would also freeze out, leaving the atmosphere clear and exposing the snowy surface.For evidence, Wong points to several “Snowball Earth” episodes on our home planet (which Titan is supposed to resemble in some respects).But how would this explain the moon’s missing ocean? This clear atmosphere would produce a different mix of molecules, so the cold snap would leave the moon’s surface covered in lots of compounds called nitriles, which would be solid rather than creating an ocean. The absence of deep oceans suggests that Titan spends more time as a snowball than as a smogball.Any way to test this theory? “Getting good enough readings of the surface composition to check this would require a future mission to Titan,” Hecht writes, meaning the test will not likely be possible in our lifetime, even if a proposed sampling mission gains approval (PhysOrg). Perhaps the New Horizons mission next year will reveal similar processes operating on Pluto. Even so, Pluto is not Titan, nor is Earth; the “Snowball Earth” theory, furthermore, is not without its skeptics (9/02/13).The short article did not address whether evidence exists for a methane reservoir under Titan’s surface, or if it’s there, how it would escape (4/16/13, 4/09/11). It also seems that nitriles would be produced in the current regime, not just during the freezing periods. Others, like Sushil Atreya, have said that the entire atmosphere (mostly nitrogen) would collapse if the methane were depleted.As we have noted before, this is an ad hoc theory rescue operation in progress. A clear prediction was made in the 1990s that spacecraft would find Titan covered in a global ocean of liquid hydrocarbons; that prediction was falsified even before the Huygens Probe landed with a thud in January, 2005. There is no evidence that Titan’s methane is being replenished.Assume, for the sake of argument, Wong’s theory works: there are cycles of methane collapse and resurrection. Let’s grant an underground reservoir of methane that outgasses into the atmosphere. Since the observed methane budget would be spent in a few tens of millions of years, how many cycles could repeat in 4.5 billion years? A generous assumption of 100,000 years per cycle would produce 45 cycles of atmospheric collapse and resurrection. A more reasonable 10,000 years would produce 450 cycles. Is that reasonable?What we observe is a fairly dry moon with few impact craters, abundant sand dunes, and significant river channels, and a few large lakes. This fits a scenario of steadily depleting methane. We think science should stick with observations, not manufacture implausible scenarios to favor one’s preferred timeline. If Titan is young, let it be young. (Visited 22 times, 1 visits today)FacebookTwitterPinterestSave分享0
Share Facebook Twitter Google + LinkedIn Pinterest OSU Extension will be partnering with Farm Credit Mid-America to hold a Farm Management School this winter to address this need from the agriculture community. The series is for all those in farming or agriculture businesses interested in finances, business plans and how to make their operation successful.January 3 Farm Mission and Business PlansJanuary 10 Record Keeping and Balance SheetsJanuary 17 Budgets and Enterprise AnalysisFebruary 7 Ag Law and Farm Transition Presenters for the series will include Bruce Clevenger, Dianne Shoemaker, Sharon Harris, Peggy Hall and Sam Custer from Ohio State University Extension. Farm Credit Mid-America team members will also be presenters. OSU Extension, Darke County would like to thank our sponsor Farm Credit Mid-America for their support in holding this program.Pre-registration and payment required. Download the full flyer and registration at http://go.osu.edu/2019farmmanagementschool . $40 per person. Registration deadline is December 26, 2018. Registration includes snacks and materials. Make checks payable to Ohio State University Extension. Mail to OSU Extension, Darke County, 603 Wagner Ave, Greenville, Ohio 45331.For more information about OSU Extension, Darke County, visit the Darke County OSU Extension web site at www.darke.osu.edu, the OSU Extension Darke County Facebook page or contact Sam Custer, at 937.548.5215.
RELATED ARTICLES Adding the insulationChoosing insulation for the interior service wall was challenging. I originally thought that I would do the work myself with batts. Intimidation set in once I realized how many wires, plumbing pipes, receptacles, and mechanical elements are integrated into the walls. Reading an article by Allison Bailes on insulation installation quality made me wonder whether it would even be possible to get a Class I installation in walls with so many complications.Luckily, Bill Gifford of Home Shield Insulation, the insulator for my attic spaces, also knows a thing or two… or three… about dense-packing fiberglass. He uses the Owens Corning ProPink wall insulation system, which is really a type of BIBS (Blown In Blanket system).The system involves stapling a breathable, semi-stretchy fabric to the service walls. The fabric is cut to allow for wall penetrations like electrical boxes, pipes, etc. Then, a pointy ended pipe attached to a flexible hose is pushed through the blanket in several places and the insulation fills the cavity. It is not quite as simple as that, so I’ll elaborate.Blowing the insulation into the walls is very methodical and appears to be an art of sorts. Bill typically starts in the bottom corner of a stud cavity and angles the pipe towards the corner. As the corner fills, the sound of the air coming out of the pipe changes, and the flow rate of the insulation delivery basically stops once the dense packing is complete for the settings on his machine. As soon as the pipe is moved, the insulation starts flowing again. A cavity can be filled pretty quickly.I suspect Bill’s technique has been developed after years of doing this type of insulation system. He interacts fluidly with the delivery hose. Once dense packing is complete in one area of the cavity, he moves the delivery pipe to another, stabs a hole and starts filling again. He was able to complete the insulation upstairs in one day. Editor’s Note: This is one of a series of blogs by David Goodyear describing the construction of his new home in Flatrock, Newfoundland, the first in the province built to the Passive House standard. The first installment of the GBA blog series was titled An Introduction to the Flatrock Passive House. For a list of Goodyear’s earlier blogs on this site, see the “Related Articles” sidebar below; you’ll find his complete blog here. Grading the Installation Quality of InsulationService Cavities for Wiring and PlumbingGetting to Know Spider Insulation Our plan of attack from the beginning was to erect all exterior service walls first and then frame the interior partitions later. The plans called for 2×4 framing 24 inches on center. The framers worked pretty quickly, and the service walls were nearly complete in just two days. To strengthen the interior petitions and service walls, we installed staggered blocking at half height to help prevent the studs from bowing, warping and twisting (see Image #2 below).Now it’s starting to look like a house!Because we would be installing drywall returns around all windows, I opted to add 1/2-inch slots to the window frames at the time they were made. To make the lives of the drywall installers easier, the rough stud openings had to align with the drywall returns so shims would not have to be used.The exterior service walls sit on 1 1/2-inch-thick strips of expanded polystyrene (EPS) foam. The foam prevents thermal bridging through the bottom wall plate to the concrete stem wall foundation. We attached the service wall to the 2×8 exterior stud wall with 5-inch #10 screws, toed through top and bottom plates. To ensure the walls were straight, we placed shims behind the screw locations and straightened the wall with string lines. Once straightened, the wall was secured by driving the screw though the top plate of the service walls, through the OSB and into the exterior wall plates. Testing the resultIt took about two days to staple the fabric and two days to complete the insulation installation. After installation was complete, he carried out some quality assurance testing with an Inspect-R gauge, a device which measures R-values using compressed air (see Image #4 below). Values acquired for the gauge were higher than 0.65, so we have at least R-15 in the interior service wall.Besides the fact that the R-value is higher than typical batts for a 2×4 cavity, the filling is much better. The insulation fills everything: it works around electrical boxes, between wires, etc. No cutting, splitting and pulling batts into place. This is a great wall system. I am much happier now looking at pink walls! I have been staring at studs for much too long. The structure is now starting to look like a house.Things are warming up! Before Christmas, the building was cold and I found it unbearable while working. The electrical inspection passed and the service was hooked up to the pole on December 22. Since then the heat has been on. Heating up a cold structure is no small feat. The amount of thermal mass in the concrete slab alone is huge, i.e. about 25 cubic meters. I estimated that it would take almost 300 kWh of electricity to bring it up to temperature!Thick walls and lots of material make for a slow heating process. With temporary construction heaters running we have chewed through almost 1500 kWh just bringing the house up to temperature. The heating load has decreased considerably since the temperature inside has leveled. The load does appear to be related to the number of people working in the house and whether or not it’s a sunny day. I have nothing quantitative at this point but it looks like the house is behaving as it should! Tackling the stairsI had been dreading the stairs because I had never worked on a staircase before. My plan was to build the rough staircase so it could be capped later. Quite a bit of planning had to go into this. I had to ensure that all the components were offset from the walls to account for drywall and a skirt board, and make sure I had room for railings.Another reason I dreaded the staircase was because the house plans called for a winder stair in order to make up the number of stairs required for the 9-foot ceilings. The winder looked confusing. However, once I investigated further I determined that two risers and a landing would work fine. The rest of the staircase just worked out. The rise and run meet code and will be very similar in feel to the staircase in my current house.There were no details in the plans about connecting interior walls to the service walls. Blocking seemed like a good method to get more insulation into the service wall, and it also provided a place to nail drywall (see Image #3 below).The weather has turned cold — then warm — then cold again. While working at the house I have had a lot of time to assess how the house behaves. With no heat source in the house and many cloudy days, the house cooled a lot. One day when it turned 14°C outside (57°F), I walked into the house and it was like an icebox! I could see my breath!Twenty-four hours later it felt just as cold and I could still see my breath despite 24 hours of warmer than seasonal temperatures. Having the sun shining the past couple of days has been welcomed. It has warmed the space significantly. Despite not having any attic insulation yet, I am pleased with the way the house responds to exterior temperature swings. It really goes to show that air sealing plays a huge part in energy savings. BLOGS BY DAVID GOODYEAR Air Sealing the PenetrationsBlower Door Test Comes Up RosesWrapping Up the Air BarrierInsulation and an Air BarrierInstalling Windows and DoorsFoam Sheathing and Window DetailsFraming and Air SealingA Well Insulated SlabFootings and Frost WallsA Final Design and Energy ModelingAn Introduction to the Flatrock Passive House
Mary Joy Tabal. FILE Photo from Cebu Daily NewsCEBU CITY—Should Cebuano marathon sensation Mary Joy Tabal be allowed to join in the Southeast Asian (SEA) Games, the Cebu City government will make sure that she will get the training that she needs for the competition. Cebu City Mayor Tomas Osmeña made an offer for the city to help fund Tabal’s trainings when she visited city hall on Tuesday morning during a courtesy call.She was accompanied by Commissioner Ramon Fernandez of the Philippine Sports Commission, among others.ADVERTISEMENT MOST READ BSP survey: PH banks see bright horizon amid dark global recession clouds View comments LATEST STORIES Palace: Duterte to hear out security execs on alleged China control of NGCP Pagasa: Storm intensifies as it nears PAR Gabuya delivered a privilege speech during the session of the city council on Tuesday afternoon to ask the Philippine Athletics Track and Field Association (Patafa) to explain why Tabal was excluded from the roster of Filipino athletes who would compete in the SEA Games where the Cebuana won silver in 2015.READ: Tabal no longer part of national teamBecause of Gabuya’s speech, the council passed a resolution asking Patafa to include Tabal, the only Filipino to compete in last Olympics marathon, in the lineup.ADVERTISEMENT BREAKING: Cop killed, 11 hurt in Misamis Oriental grenade blast Sports Related Videospowered by AdSparcRead Next Every 18 seconds someone is diagnosed with HIV Olympian Ryan Lochte says he thought about suicide after Rio fiasco Cayetano dares Lacson, Drilon to take lie-detector test: Wala akong kinita sa SEA Games The city is just waiting for Tabal to make a formal budget request that will include a breakdown of her training needs and costs, said Councilor Jerry Guardo, head of the council’s sports committee.He added the mayor also made a commitment to “fight” for Tabal’s inclusion in the SEA Games.FEATURED STORIESSPORTSSEA Games: Biñan football stadium stands out in preparedness, completionSPORTSPrivate companies step in to help SEA Games hostingSPORTSMalditas save PH from shutoutCouncilor Eugenio Gabuya, deputy mayor for sports, said the budget for Tabal’s training can be charged to the mayor’s discretionary fund or Philippine Amusement and Gaming Corp. funds whichever is available.“As to how much (funding is needed) that is still to be determined,” he added. Robredo: True leaders perform well despite having ‘uninspiring’ boss PLAY LIST 02:49Robredo: True leaders perform well despite having ‘uninspiring’ boss02:42PH underwater hockey team aims to make waves in SEA Games01:44Philippines marks anniversary of massacre with calls for justice01:19Fire erupts in Barangay Tatalon in Quezon City01:07Trump talks impeachment while meeting NCAA athletes02:49World-class track facilities installed at NCC for SEA Games BREAKING: Cop killed, 11 hurt in Misamis Oriental grenade blast Don’t miss out on the latest news and information. Lacson: SEA Games fund put in foundation like ‘Napoles case’
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Former Chelsea midfielder Oscar was handed an eight-match ban by Chinese football authorities on Thursday for his role in a brawl that broke out during Shanghai SIPG’s draw with Guangzhou R&F at the weekend.The Brazilian, who moved to China for a record transfer fee in January, was also fined 40,000 yuan (5,855 dollar) by the Chinese Football Association in the latest move by the country’s authorities to stamp out indiscipline.”According to the referee’s report, video evidence and a written explanation from the parties involved… Oscar offended opposing players in an immoral manner, leading to a massive brawl which has had a very bad influence on the Chinese Super League’s reputation,” an official statement said.The incident was triggered in the dying seconds of the first half of Sunday’s game after Oscar had set up Hulk to score his side’s equaliser, with Guangzhou players complaining to officials the strike should have been ruled out for offside.Soon after the restart, Oscar deliberately kicked the ball at two Guangzhou players, provoking a response that led to a scuffle on the halfway line.Oscar was pushed to the ground by Guangzhou’s Chen Zhizhao, while R&F’s Li Tixiang and Fu Huan of SIPG were sent off for their part in the ensuing altercation.The 25-year-old joined SIPG from Chelsea in January for an Asian record transfer fee of 60 million euros (66.96 million dollar) as Chinese Super League clubs continued a spending spree that has seen several high-profile acquisitions in recent years.advertisementOscar’s purchase was the third time in a 12-month period the Asian transfer record had been broken with the fee paid for the Brazilian surpassing that paid by SIPG for Hulk seven months earlier.His sanction is another sign Chinese authorities intend to crack down on poor behaviour as the profile of the Chinese Super League grows overseas.Shanghai Shenhua’s Qin Sheng was given a six-month ban in March for stamping on the foot of Belgium international Axel Witsel in a game that was televised internationally.