Underground experiment confirms what powers the sun

first_imgScientists have long believed that the power of the sun comes largely from the fusion of protons into helium, but now they can finally prove it. An international team of researchers using a detector buried deep below the mountains of central Italy has detected neutrinos—ghostly particles that interact only very reluctantly with matter—streaming from the heart of the sun. Other solar neutrinos have been detected before, but these particular ones come from the key proton-proton fusion reaction that is the first part of a chain of reactions that provides 99% of the sun’s power.The results also show that the sun is a remarkably steady power source. Neutrinos take only 8 minutes to get from the sun’s core to Earth, so the rate of neutrino production that the team detected reflects the amount of heat the sun is producing today. It just so happens that this is the same as the amount of energy now being radiated from the sun’s surface, even though those photons have taken 100,000 years to work their way from the core to the surface. Hence, the sun’s energy production hasn’t changed in 100 millennia. “This is direct proof of the stability of the sun over the past 100,000 years or so,” says team member Andrea Pocar of the University of Massachusetts, Amherst.The core of the sun is a fiery furnace so hot and dense that protons—nuclei of hydrogen, the sun’s main constituent—slam together with such force that they fuse, producing a deuterium nucleus (heavy hydrogen, made of a proton and a neutron) plus an antielectron and a neutrino. This is the start of a whole sequence of reactions: Protons collide with deuterium to produce helium-3; helium-3s combine to give helium-4 plus protons; other reactions produce lithium, beryllium, and boron. Many of these reactions produce neutrinos, but the vast majority of the neutrino flux from the sun is produced by the original proton-proton, or pp, reaction. “The pp reaction is the most basic process. Everything that goes on in the sun stems from it,” says Steve Biller of the University of Oxford and U.K. spokesperson for the SNO+ neutrino detector under construction in Canada, who was not involved in the new work.Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*)Researchers have been detecting neutrinos since the 1960s. Initially, a two-thirds deficit in the detection rate confused the results. It turned out that neutrinos could transform from one type to another as they fly through space, but detectors were sensitive to only one of the three types. Once this “neutrino problem” was resolved, neutrino observatories went on to detect neutrinos from almost all the predicted reactions in the sun—but not the pp reaction. What makes the pp reaction hard is that the neutrinos have very low energy that is about the same as the energy of various radioactive decays that happen on Earth, making it easy for an earthbound detector to confuse a decay with a neutrino event. “Detecting neutrinos of this kind is an almost impossible thing to do. You need very low background levels and a lot of patience,” Biller says.The Borexino detector at the Gran Sasso National Laboratory, 1400 meters below the Italian Apennines, is made up of a spherical transparent vessel filled with 300 tonnes of highly pure pseudocumene, a benzenelike liquid. Neutrinos pass easily through the overlying rock, but occasionally one will hit a nucleus in this “scintillator” liquid, producing a flash of light that is detected by an array of detectors positioned all around the sphere. Such detectors are always situated deep underground, to protect them from cosmic rays, and are surrounded by buffer layers of liquids to fend off radioactive decays in the rocks.Despite these efforts, to detect pp neutrinos the Borexino collaboration had to go through an especially lengthy purification campaign to reduce the levels of radioactive contaminants in the scintillator liquid—particularly krypton-85, a byproduct of nuclear testing and reprocessing that now pervades the atmosphere and produces a decay signal very similar to that from the arrival of a pp neutrino. “Any tiny air leak and krypton-85 will get inside,” Pocar says. The researchers, Biller says, “really pushed the cutting edge, achieving ridiculously low levels of radioactive contamination.”There followed a year and a half of data collection and a year of analysis “to show it was not background or a detector effect,” Pocar says. After painstakingly removing multiple sources of background signals, the team was left with a neutrino flux of 66 billion per square centimeter per second, close to the standard solar model prediction of 60 billion, they report online today in Nature.“They did a stellar job in doing this—incredibly impressive,” Biller says. “They’re peeling back the branches to get to the trunk of the main process.”last_img read more

UBT Watch

first_imgWe’re excited to announce a new website all about the effort to get freelancers exempted from NYC’s Unincorporated Business Tax. UBTWatch.org goes live today, with videos, press, and a white paper about the senseless imposition of this tax on independent workers. In a few weeks, we’ll bring you updates with expanded features, including partner organizations, a blog, and ways to sign up and get involved.For now, visit the site and get educated about the issues. If you’re from an organization, such as a professional association, that would like to support the cause, let us know!last_img

Yahoo announced that its highly scalable low late

first_imgYahoo announced that its highly scalable, low latency pub-sub messaging system is now open-source. The system provides pub-sub messaging semantics and is what Yahoo uses to provide messaging as a hosted service.Developers that use Pulsar can set up a centrally managed cluster to provide pub-sub messaging as a service. Since the system is horizontally scalable, storage capacity can be expanded by adding additional servers to the pool.Pulsar has a set of APIs that manage the service, like account-management activities that provision users, allocate capacity, and monitor the service as a whole. Pulsar also provides security by a pluggable authentication scheme.Yahoo is currently working on improvements for Pulsar, including migrating topics between brokers in under a second, and it wants to provide additional language bindings for Pulsar. Developers can check out Pulsar on GitHub here.SourceClear supports Vulnerable Method detection for Java, PythonSourceClear now supports Vulnerable Method detection for both Java and Python projects. It will also begin notifying developers of the vulnerable libraries they are using and will point out exactly where the vulnerable code is being used. SourceClear analyzes bytecode to support Vulnerable Methods in Java, which gives it types and static name resolution. All of this information allows SourceClear to build an accurate call graph for Java, but with Python, things are more difficult, according to a blog post by Paul Ambrosini and Darius Foo, part of the product team at SourceClear.Python packages are distributed on PyPl in source-code form, which means SourceClear needs to “get creative to compute or infer types in order to resolve their names,” wrote Ambrosini and Foo.Once a developer installs or upgrades the latest agent, they can scan an example repository to see the Vulnerable Method Detection for Python in action. The Vulnerable Methods feature for Python and Java is available to all SourceClear Pro customers, and developers can start a free trial today as well.Announcing BES Cloud by HuaweiAt the Huawei Connect 2016 conference this week, Huawei announced its BES Cloud solution. The cloud will leverage global cloud infrastructure as well as scalable software features.The BES Cloud includes the BSS Lite Cloud and Commerce Cloud. The Commerce Cloud can be integrated into on-premise systems, and it contains a cloud-based multi-tenant architecture that employs metadata-driven modeling and auto-scaling, according to Huawei.The solution supports IT and business agility with integrated feature sets that shorten the time to market. Also, according to Huawei, it can be deployed and go live in three months.last_img read more