Dawn Mission scientists were surprised to see this asteroid (dwarf planet Ceres) with a water cycle and evidence of rapid geological changes.For planetary scientists accustomed to thinking in billions of years, what the Dawn spacecraft revealed about Ceres must have been a shock. A press release from Jet Propulsion Laboratory says, “NASA Dawn Reveals Recent Changes in Ceres’ Surface.” Previously, the spacecraft had detected carbonates that must have been produced in an ocean. Now, they are seeing changes within the observation period of the mission.Water ice is not stable on the surface of Ceres over long time periods unless it is hidden in shadows, as in the case of Juling. Similarly, hydrated carbonate would dehydrate, although over a longer timescale of a few million years.“This implies that the sites rich in hydrated carbonates have been exposed due to recent activity on the surface,” Carrozzo said.The great diversity of material, ice and carbonates, exposed via impacts, landslides and cryovolcanism suggests Ceres’ crust is not uniform in composition. These heterogeneities were either produced during the freezing of Ceres’ original ocean – which formed the crust – or later on as a consequence of large impacts or cryovolcanic intrusions.“Changes in the abundance of water ice on a short timescale, as well as the presence of hydrated sodium carbonates, are further evidence that Ceres is a geologically and chemically active body,” said Cristina De Sanctis, VIR team leader at the Institute of Astrophysics and Planetary Science.Two papers announce the discoveries. One, in Science Advances, speaks of the “detection of water ice in a mid-latitude crater and its unexpected variation with time,” with changes visible in just six months. “The reported variation on Ceres’ surface indicates that this body is chemically and physically active at the present time.”The smaller a body, the more rapidly it should have cooled and become inactive in 4.5 billion years. Ceres is much smaller than Pluto (which also showed unexpected activity when New Horizons flew past in 2015; see review 19 March 2016), and smaller than Saturn’s moon Dione. The other asteroid target of Dawn, Vesta, also showed evidence of watery youth (28 Oct 2011, 9 Feb 2015). At the end of the paper, the scientists scramble for possible sources of energy to keep Ceres active.The variation of superficial water ice occurring in the short time frame covered by these observations provides new scenarios for Ceres’ evolution. It indicates an active body and reinforces not only the link with the icy solar system objects but also the uniqueness of Ceres, given its present location in the main belt.The other paper by Carrozzo et al. in Science Advances tries to understand the presence of carbonates on Ceres.The correlation of Na carbonates with some extrusive constructs suggests that at least some Na carbonates are transported to, or near to, the surface by ascending subsurface fluids in several areas of Ceres. However, the association of Na carbonate with young craters could be consistent with the material mobilized or created by impact-induced heating. The data are not sufficient to fully discriminate among the possible mechanisms, and likely, the types of Na carbonates and the observed distribution are the results of a combination of different processes.Whatever happened, the detection of carbonates on the surface “provides major constraints on Ceres’ chemical evolution,” the authors say.NH4 salts are speculated to be unstable over geologic time. Hydrated sodium carbonates are not stable on airless surfaces and dehydrate upon exposure to vacuum and irradiation over Myr timescales. Destabilization on the surface involves both dehydration and decarbonation; for example, Na2CO3·H2O in Na2CO3 + H2O(g). The detection of hydrated Na carbonates supports an aqueous origin of Na carbonates followed by their partial decomposition (mainly dehydration) in surface environments. This implies that sites rich in hydrated carbonates have been formed/exposed recently (a few million years), and dehydration of hydrated Na carbonates is still ongoing. This is in accordance with crater counting and modeling that predict recent formation, within tens to hundreds of millions of years.The different chemical forms of the sodium carbonate, their fresh appearance, morphological settings, and the uneven distribution on Ceres indicate that the formation, exposure, dehydration, and destruction processes of carbonates are recurrent and continuous in recent geological time, implying a still-evolving body and modern processes involving fluid water.They still make estimates into the millions of years, but those fall far short of the assumed 4.5 billion years for the origin of the solar system, sometimes called “geologic time” (what we dub “Darwin Years“).Ceres joins the young, active object club, a large and growing list. One wonders if planetary scientists will ever find any object that lives up the assumed age of the solar system. Does this object look billions of years old to you?DAWN 10th anniversary image (false color) of Ceres, centered on Occator Crater with its bright sodium carbonate deposits. (NASA/JPL)(Visited 532 times, 1 visits today)FacebookTwitterPinterestSave分享0
(Image: Pixabay)Johannesburg, Monday 11 April 2016 – South Africans want to be “constantly informed about current affairs within their communities and country,” finds Brand South Africa’s 2015/16 Domestic Perceptions study.The study further suggests that citizens want easy accessible information provided to them, with the most reliable and trusted sources being family, friends/colleagues, followed by mainstream media sources like television and news radio broadcasts.In order to understand the extent to which South Africans trust sources of information, respondents were asked to rate the various information sources available at their disposal. Family, friends & colleagues; television news; and radio news are the top three trusted sources of information. Online social networking and related sources of information are the least trusted of all possible sources.Of 2,536 respondents who participated in the survey, over 60% said that they have access to the internet. Of these, 80% use the web for social media, 61% for research purposes, 37% for applications and 33% for access to current affairs and news.Other media consumption factors from the study included that 92% of respondents own a cell phone, 30% use laptops and 9% use tablets. Just over half the respondents indicated that they listen to radio everyday with Metro FM, Lesedi FM and Umhlobo Wenene being among the most popular radio stations.A quarter of the population read newspapers every day, with the most commonly read publications being the Daily Sun at 34%, Isolozwe at 8%, the Sunday Times at 5%, Beeld at 4%, Sowetan at 4% and The Citizen at 3%.There is consensus that the media portrays more negative than positive information and stories about South Africa, with over 62% of respondents indicating that the media in South Africa is too negative about the country.Brand South Africa’s CEO Mr Kingsley Makhubela, reflecting on the outcomes of the study, said: “It is encouraging that freedom of media, speech and access to information remains one of the greatest successes of our 22 years of democracy. The right to information is a pillar of any free society and South Africans must continue to embrace this fundamental freedom in our country.”Follow the conversation on @Brand_SA #SANationBrand
Controversial self-styled godman, Swamy Nithyananda, has found himself in another controversy with allegations of “illegally confining” two daughters of a Bengaluru-based couple.A petition has been filed in the Gujarat High Court by the couple seeking the court’s help to get back two daughters allegedly “illegally confined” from an ashram set up by Nithyananda, who faces rape charges. The petition is set to be heard by the court on Wednesday.The petitioners, Janardana Sharma and his wife, in their habeas corpus petition said they had admitted their four daughters in an educational institution run by the godman in Bengaluru in 2013 when they were in the age group of 7-15. However, their daughters were allegedly shifted to another institution in his ashram in Ahmedabad without their consent. When they learnt about this, that their daughters were this year shifted to another branch of Nithyananda Dhyanapeetham, named Yogini Sarvagyapeetham, situated on the premises of Delhi Public School in Ahmedabad, they rushed to Ahmedabad and tried to meet them, but the officials in the place did not allow them inside.When officials of the institute refused to let them meet their daughters, the petitioners first sought the local police help. The couple could bring back their two minor daughters with the help of police and Protection of Child Rights Commission. But their elder daughters, Lopamudra Janardhana Sharma (21) and Nandhita (18), refused to come with them.Based on the Sharma family’s complaint, the Ahmedabad Rural police lodged an FIR against Nithyananda and other officials of the Ashram.“Our team is probing the matter,” Ahmedabad (Rural) Superintendent of Police R.V. Asari said.In their petition, the couple alleged that their two younger daughters were kidnapped and kept in illegal confinement for more than two weeks and were deprived of sleep.The Sharmas have urged the court to direct the police as well the institute’s authorities to produce their daughters, who, they alleged, are being kept under “illegal confinement,” before the court and hand them over to them.Cong. slams govt.Meanwhile, the Gujarat Congress slammed the BJP government in the State for not initiating action against Nithyananda Ashram. “It is a well-known fact that Nithyananda enjoys protection from the State government despite the fact that many children are being confined in the ashram against the wishes of their parents,” Gujarat Congress spokesman Manish Doshi said on Tuesday.
Ouch: Karate Thiagarajan (with mike) presides over the pandemoniumWhen the J. Jayalalithaa government introduced the one-man-one-post rule, aimed at clipping the wings of M.K. Stalin, Chennai mayor and MLA, the DMK went curiously silent.But when Stalin finally shed his mayoral robes last month leading Deputy mayor “Karate” Thyagarajan to plonk,Ouch: Karate Thiagarajan (with mike) presides over the pandemoniumWhen the J. Jayalalithaa government introduced the one-man-one-post rule, aimed at clipping the wings of M.K. Stalin, Chennai mayor and MLA, the DMK went curiously silent.But when Stalin finally shed his mayoral robes last month leading Deputy mayor “Karate” Thyagarajan to plonk himself on the mayor’s seat, there was chaos in the Chennai Corporation.At a council meeting of the corporation chaired by Thyagarajan for the first time on June 28, DMK members came in cars sporting the mayoral flag. Clad in black and belligerent, they frequently interrupted the meeting and walked out – and in – in protest.When TMC leader P. Vetrivel passed an unsavoury remark on the DMK’s conduct, members took offence and a minor fisticuff ensued.Surprisingly, Thyagarajan, contrary to what his prefix would suggest, sat rock-like on the mayoral throne vowing to carry out “all Amma’s orders”.
CLEVELAND – The Yankees’ 5-4 in 14 innings win took five hours and 32 minutes, going into the books after the Yankees absorbed a heavy dose of bad news, losing ace right-hander Masahiro Tanaka to the 15-day disabled list with inflammation in his right elbow. On what was a particularly stressful day for the Yankees, shaking hands and celebrating a late-night victory helped take some of the sting out of their afternoon.Jacoby Ellsbury connected for a two-out solo home run in the top of the 14th, giving the Yankees something to smile about at the conclusion of a 5-4 victory over the Indians on Wednesday night at Progressive Field.“That’s what it felt like, it was going to take a home run to get a run across,” Ellsbury said. “Our bullpen pitched unbelievable to give us a chance to win that game. It was a nice team win.”Carlos Beltran also sustained two small facial fractures in a batting-cage mishap and Brett Gardnerwas held out of the lineup with an abdominal strain, but on the positive side, Mark Teixeira homered twice and Brandon McCarthy hurled 6 2/3 solid innings in his Yankees debut.“No matter what happens before the game, in between the lines — whether it’s nine or 14 innings — we’re just going to keep playing hard,” Teixeira said. “That’s the only thing we can do. Don’t feel sorry for ourselves, go out there and try to win games.”Ellsbury’s homer off Vinnie Pestano made a winner of rookie Chase Whitley, who hurled two scoreless innings in his first outing since being bumped out of the rotation. David Robertson, the seventh Yankees reliever of the night, pitched a scoreless 14th inning for his 22nd save.“That’s a tough game to lose for either side,” Yankees manager Joe Girardi said. “Both bullpens did an exceptional job. It came down to one big hit.”The Indians had the winning run 90 feet away in the 10th inning, as David Huff issued walks to three batters he faced, loading the bases with free passes to Michael Brantley, Carlos Santana andLonnie Chisenhall.Shawn Kelley entered and pitched out of the jam, striking out Nick Swisher and inducing a ground ball from David Murphy to wriggle free. New York’s bullpen combined to hold Cleveland to three hits over 7 1/3 innings with nine strikeouts.“Bases loaded, one out, any fly ball or solid contact gets the job done for them,” Kelley said. “I was just trying to make a big pitch.”Teixeira atoned for a first-inning throwing error with his first multi-homer game in nearly two years, slugging a solo blast in the fourth and a two-run shot in the fifth, both off Tribe starter Josh Tomlin.The second blast — Teixeira’s 17th of the season — gave the Yankees their first lead of the night, marking his 37th multi-homer game and his first since July 13, 2012, against the Angels.“I just got lucky. I just put a couple of good swings on some pitches,” Teixeira said. “I haven’t really been swinging the bat well the last few weeks, so it was just a good day to get two homers because we needed it.”McCarthy settled down after three unearned runs crossed the plate in the first inning, a frame prolonged when Teixeira hit Brantley with a throw as he slid into second base, loading the bases. Chisenhall knocked home a run with a groundout and Swisher delivered a two-run single.Santana also logged a fifth-inning RBI single off McCarthy, who was acquired from the D-backs on Sunday in exchange for left-hander Vidal Nuno. He scattered nine hits with a walk and three strikeouts, recording 13 ground-ball outs to keep his infield busy.“Results-wise it was all right, but I didn’t feel sharp early on, I was struggling with a few things,” McCarthy said. “I feel like I did a decent job of getting it back, but [catcher Brian] McCann was fantastic at keeping in touch with me between each inning, coming up, letting me know what he was seeing. We were able to make adjustments and it made it way easier for me.”McCann lifted a sacrifice fly as part of a three-run fifth inning off Tomlin, who worked seven innings and allowed four runs on eight hits. He walked none and struck out five before yielding to the bullpen.“These ones are always tough when you lose them,” Ellsbury said. “Obviously when you win them, it’s nice for the momentum.”Bryan Hoch for MLB.com.TweetPinShare0 Shares