AstroTalk:BehindthenewsheadlinesofMarch2017RicharddeGrijs(何锐思)(KavliInstituteforAstronomyandAstrophysics,PekingUniversity)‘Citizenscience’ontheriseThankstotheInternet,amateurvolunteersknownas‘citizenscientists’canreadilydonatetheirtimeandefforttoscience—infieldsrangingfrommedicinetozoologytoastrophysics.Theastrophysicsproject‘SpaceWarps’offersacompellingexampleofwhycitizensciencehasbecomesuchapopulartoolandhowvaluableitcanbe.Inlate2015,inapairofresearchpapers,SpaceWarpsannouncedthediscoveryof29newgravitationallenses.Thesearcedorblobbyfeatures,seeninimagesofdeepspace,areactuallydistantgalaxieswhoselighthasbeenbentbythemassofforegroundgalaxies.Scientistsprizetheserare,cosmicphenomenabecausetheyoffertantalizingglimpsesofobjectstoodistantanddimtobeotherwiseseen.Thishauloflenseswasobtainedoveran8monthperiodbyabout37,000SpaceWarpsvolunteers,whoreviewed430,000digitalimagesinamassive,onlinephotolibrary.Automatedcomputerprogramshaveidentifiedmostoftheapproximately500gravitationallensesdiscoveredtodate.However,computersfailedtoflagthe29lensestheSpaceWarpsvolunteersspotted.

“Humanbeingsareverygoodatpatternrecognition.Thedynamicrangethatoureyesandourbrainsofferismuchgreaterthanacomputeralgorithm,”saidAnupreetaMore,aprojectresearcherattheKavliInstituteforthePhysicsandMathematicsoftheUniverse(KavliIPMU)attheUniversityofTokyoandaco-principalinvestigatorforSpaceWarps.

MoreandhercolleaguesdesignedSpaceWarpstotakeadvantageofthesehumanabilities.Sofar,besidesthe29newgravitationallenscandidates,SpaceWarpershavealsoturnedupanever-before-seenlensingscenariothatlookslikearedringintheproject’simagearchive.Researchersarestillworkingoutthesourceofthisredring,whichtheysuspectisthewarpedfeaturesofabackgroundgalaxycontainingasupermassiveblackholeaswellasregionsofnewstarformation.Discoveringsuchstrange,newphenomenaisahallmarkofcitizenscience.AmongthemostfamousexamplesisHanny’sVoorwerp,agalaxy-sizegasclouddiscoveredin2007inaprojectcalled‘GalaxyZoo,’oneoftheearliestastronomyprojects.

“Citizenscientists...havereallyenabledustoproduceimportantfindings.They’veinspireduswiththeirdedicationandproductivity,”saidAprajitaVerma,aseniorresearcherinthedepartmentofphysicsattheUniversityofOxford(UK)andalsoaco-principalinvestigatorforSpaceWarps.

“We’velearnedfromouranalysisthatbasicallyanyonewhojoinsSpaceWarpshasanimpactontheresults.”

Asastronomicaldatasetscontinuetoincreaseinsize,therewillbenoshortageofopportunitiesforeagercitizenscientists.Forinstance,theLargeSynopticSurveyTelescope,expectedtostartoperationsin2022,willcollect30terabytesofdatapernightasitobservesthewholeskyeveryfewdaysfromthesouthernhemisphere.Computerizedobject-recognitionprogramswillcertainlyplayanimportantroleinanalysingthesedata,buthumanvolunteersarelikelytoremainintegral.

“Ithinktherewillbecitizeninvolvementforalongwhileanditwillbecomemoreinterestingasweusemachinestodomoreoftheroutineworkandfilterthedata,”saidChrisLintott,aprofessorofastrophysicsandthecitizenscienceleadattheUniversityofOxford.“Thetasksforcitizenscientistswillinvolvemorevariedthings—moreoftheunusual,Hanny’sVoorwerp-typeofdiscoveries.”

Lintott,whoisalsoaco-founderofGalaxyZooandtheprincipalinvestigatorfortheZooniversecitizensciencewebportal,added,

“Plus,alotofunusualdiscoverieswillneedtobefollowedup,andI’dliketoseecitizenscientistsgetfurtherintotheprocessofanalysis.Withoutthem,Ithinkwe’regoingtoendupwithapileofinterestingobjectswhichprofessionalscientistsjustdon’thavetimetodealwith.”

Anewcitizen-scienceprojectlaunchedthispastmonth,on22March2017.Itsaimistorescuetensofthousandsofpotentiallyvaluablecosmicimagesthataremostlydeadtoscienceandbringthemfullybacktolife.Called‘AstronomyRewind,’theeffortwilltakephotographs,radiomaps,andothertelescopicimagesthathavebeenscannedfromthepagesofdustyoldjournalsandplacethemincontextindigitalskyatlasesandcatalogues.Anyonewillthenbeabletofindthemonlineandcomparethemwithmodernelectronicdatafromground-andspace-basedtelescopes,makingpossiblenewstudiesofshort-andlong-termchangesintheheavens.

“There’snotellingwhatdiscoveriesawait,”saysAlyssaGoodmanfromtheHarvard–SmithsonianCenterforAstrophysics(CfA),oneoftheproject’sfounders.“Turninghistoricalscientificliteratureintosearchable,retrievabledataisliketurningthekeytoatreasurechest.”

AstronomyRewindisthelatestcitizen-scienceprogrammeontheZooniverseplatform,whichdebutedatOxfordUniversityadecadeagowithGalaxyZooandnowhostsmorethan50active‘people-powered’projectsacrossavarietyofscientificdisciplines.Aftergoingthroughashortexercisetolearnwhatthey’relookingfor,userswillviewscannedpagesfromthejournalsoftheAmericanAstronomicalSociety(AAS)datingfromthe19thCenturytothemid-1990s,whentheSocietybegan

publishingelectronically.Volunteers’firsttaskwillbetodeterminewhattypesofimagesthepagescontain:Photosofcelestialobjectswith(orwithout)skycoordinates?Mapsofplanetarysurfaceswith(orwithout)gridsoflatitudeandlongitude?Graphsorothertypesofdiagrams?Theimagesofmostinterestareoneswhosescale,orientation,andskypositioncanbenaileddownbysomecombinationoflabelsonoraroundtheimagesplusdetailsprovidedinthetextorcaptions.Picturesthatlacksuchinformationbutclearlyshowrecognizablestars,galaxies,orothercelestialobjectswillbesenttoAstrometry.net,anautomatedonlineservicethatcomparesastrophotostostarcataloguestodeterminewhatareasofskytheyshow.Modernelectronicastronomicalimagesoftenincludeinformationaboutwheretheyfitonthesky,alongwithwhichtelescopeandcamerawereusedandmanyotherdetails.Butsuch‘metadata’areusefultoresearchersonlyiftheoriginalimagefilesarepublishedalongwiththejournalarticlesinwhichthey’reanalysedandinterpreted.Thisisn’talwaysthecase—althoughit’sbecomingmorecommon—sosomeelectronicjournalpageswilleventuallyberunthroughAstronomyRewindandAstrometry.nettoo.Thankstothesehuman-assistedandautomatedefforts,manythousandsof‘newold’imageswillultimatelyendupinNASA’sandothers’datarepositoriesalongsidepicturesfromtheHubbleSpaceTelescope.TheywillalsobeincorporatedintotheAstronomyImageExplorer,aserviceoftheAASanditsjournal-publishingpartner,theUKInstituteofPhysics(IOP)Publishing,andviewableinWorldWideTelescope,apowerfuldata-visualizationtoolanddigitalskyatlasoriginallydevelopedbyMicrosoftResearchandnowmanagedbytheAAS.ThescansofpagesfromtheAASjournals—TheAstronomicalJournal(AJ),TheAstrophysicalJournal(ApJ),ApJLetters,andtheApJSupplementSeries—areprovidedbytheAstrophysicsDataSystem(ADS),aNASA-fundedbibliographicserviceandarchiveattheSmithsonianAstrophysicalObservatory(SAO),partoftheCfA.AstronomyRewindisbuiltonafoundationlaidbytheADSAll-SkySurvey,anearlierefforttoextractscientificallyvaluableimagesfromoldastronomypapersusingcomputers.

“Itturnsoutthatmachinesaren’tverygoodatrecognizingcelestialimagesondigitizedpagesthatcontainamixtureoftextandgraphics,”saysAlbertoAccomazzi(SAO/ADS).“Andtheyreallygetconfusedwithmultipleimagesoftheskyonthesamepage.Humansdomuchbetter.”

Accomazzi’sCfAcolleagueGoodman,whorunsacollaborationcalled‘SeamlessAstronomy’todevelop,refine,andsharetoolsthatacceleratethepaceofastronomicalresearch,helpedbringADSandZooniversetogether.AccordingtoZooniverseco-investigatorLauraTrouille(AdlerPlanetarium,USA),1.6million

volunteershavemadeabout4billionimageclassificationsorothercontributionsusingtheplatformoverthelast10years.

“Thisisn’tjustbusywork,”saysTrouille.“Zooniverseprojectshaveledtomanysurprisingdiscoveriesandtomorethan100peer-reviewedscientificpublications.”

IfAstronomyRewindattractsvolunteersinnumberscomparabletootherastronomyprojectsonZooniverse,Trouilleestimatesthatatleast1,000journalpageswillbeprocesseddaily.Eachpagewillbeexaminedbyfivedifferentcitizenscientists;themoreofthemagreeonwhatagivenpageshows,thehighertheconfidencethatthey’reright.Itshouldn’ttakemorethanafewmonthstogetthroughtheinitialbatchofpagesfromtheAASjournalsandmovemostofthemontothenextstage,wherethecelestialscenestheycontainwillbeannotatedwithessentialinformation,extractedintodigitalimages,mappedontothesky,andmadeavailabletoanyonewhowantsaccesstothem.

“AstronomyRewindwillbreathenewlifeintooldjournalarticlesandputlong-lostimagesofthenightskybackintocirculation,andthat’sexciting.Butwhat’smoreexcitingiswhathappenswhenavolunteeronZooniverselooksatoneofourjournalpagesandgoes,‘Hmm,that’sodd!’That’llbethefirststeptowardlearningsomethingnewabouttheUniverse.”

Butastronomyisnottheonlydisciplinethathasbenefitedtremendouslyfromtheinvolvementofcitizenscientists.AwildlifeagencystudyingtheStellersealiondeclineinAlaska’sAleutianIslandshasalsobeenlookingforhelpfromcitizenscientists.Volunteersdon’tneedraincoatsorrubberbootstopitchin,justeyeballsandacomputerscreen.FisheriesresearchersattheU.S.NationalOceanicandAtmosphericAdministration(NOAA)wantthemtosortthrough500,000imagescapturedby20camerasatsixremotesites.Thejobissimple:Flagphotosthatshowsealions.NOAAFisheriesbiologistKatieSweeneyisspecificallylookingfor256Stellersealionscapturedstartingin2011thatwerepermanentlymarkedbybranding,allowingthemtotrackmovementpatterns.Theimagesortingtellsresearcherswhichphotosaremostimportanttoreview.

“Ifweseetheseanimalsovertime,wecanestimatetheirsurvival,”SweeneysaidfromherofficeattheAlaskaFisheriesScienceCenterinSeattle(USA).

Stellersealionsarethelargestmembersoftheearedsealfamily.AdultmalesintheAleutianscangrowto2,400poundsandfemalesto800pounds,Sweeneysaid.TheyarefoundintheNorthPacificfromJapanandRussiatoAlaskaandasfarsouthastheChannelIslandsoffthecoastofSouthernCalifornia.Thewesternpopulation,fromPrinceWilliamSoundtotheAleutians,waslistedasendangeredin1997.Theyfelltotheirlowestnumbersin2003andthepopulationsincethenhasincreasedjust2.7%annually.Sealionsinthefar

westernAleutianswereespeciallyhardhit,decliningby94%overthelast30years.Nooneknowswhy.TrackingmarkedsealionshasindicatedtheyarenotsimplymovingeasttootherpartsofAlaskaorwesttoRussia.Contaminantsandpoornutritionareamongthepossibilities,butanswersdon’tcomeeasybecauseoftheexpenseandtimeneededtoreachtheremotelocationswheretheylive.NOAAin2012turnedtoremotecamerastogathermoreinformation.The20camerasworkyear-round,snappingadigitalphotographevery10to30minutesduringdaylight.

“Wegetonaresearchvesselandweareout1,200milesintheAleutianIslands,”Sweeneysaid.“WegotoeachsiteandhavetopullouttheSDcardsanddownloadthem.”

Ahandfulofpeoplewhovolunteeredtochecktheimagescouldnotkeepupwiththevolume.Computeranalysiswasnotanoptionbecausecreatinganautomatedprocesswouldhavebeenexpensiveandtimeconsuming,Sweeneysaid.Researchersturnedtocrowdsourcing.They’reworkingwiththeZooniverseplatform.OnevolunteerwasCharleneAndersson,ateacheratMeadowsElementarySchoolinValencia,California(USA),whosawtheprojectasanopportunitytoengageherstudentsincurriculumonanimalsandtheirhabitats.Thatledtoquestionsonendangeredspeciesandcausesforsealiondecline.

“They’resoexcitedaboutcontributingtotheproject,”Anderssonsaid.“They’recominginandsaying,‘Canwegoonthesiterightnow?’”

Sweeneyhadhopedthatvolunteerswouldfinishthatfirstbatchinaboutthreemonths,whenshewasduetoleavefortheAleutianstocountsealionsandbrandmoreofthem.Instead,thecitizenscientistssurprisedherandzippedthroughthefirstbatchinadayandahalf.Researchershavesincelaunchedasecondphaseoftheproject:Askingvolunteerstolookatphotoswithsealionstoseeifanyanimalsarecarryingthepermanentmarksthatrevealwherethesealionswereborn,theirageandtheirgender.Thesortingwillhelpresearchersfocusonthemostimportantimages.Citizensciencehasbeenaroundformorethanadecade,andithasmaturedtobecomeausefulinputtotheworkofprofessionalscientists.Therearenumerousprojectsonecancontributeto,soifyouwantto‘getyourhandsdirty’andcontributetoscience,youarestronglyencouragedtogetinvolved!

Figure1:AtleftisaphotographoftheOrionNebulafrompage396oftheJune1905AstrophysicalJournal—withoutcoordinatelabelstofixitscelestialpositionandorientation.Astrometry.netwasabletorecognizethestarpattern,afterwhichtheimagewasrotatedmorethan180°toputnorthup,andplacedincontextontheskyinWorldWideTelescope.(Credit:AmericanAstronomicalSociety,NASA/SAOAstrophysicsDataSystem&WorldWideTelescope.)

Figure2:29gravitationallenscandidatesfoundthroughSpaceWarps.(Credit:SpaceWarps,Canada-France-HawaiiTelescopeLegacySurvey)

Figure3:Howonegalaxy’simageappearsdistortedduetoanothergalaxy.(Credit:KavliIPMU)

Figure4:Therearesomanygalaxies,youcanwritewiththem!(Credit:galaxyzoo.org,CCBY-SA)

Figure5:Classifythesegalaxiesfrom‘GalaxyExplorer:’agalaxywithabrightbulge,abarredspiral,andafeaturelessgalaxy.(Credit:ABCScience)

Figure6:Hanny’sVoorwerpisthegreenblobbelowthegalaxy.It’sastreamofgasthat’smakingstars.(Credit:NASA,ESA,W.Keel/UniversityofAlabama,andtheGalaxyZooTeam)

Figure7:It’seasytomeasurethesizeofthegalaxy—movethegreensquaresuntiltheringissnugaroundthegalaxy.

Figure8:ResearchersobservingStellersealions.(Credit:RussAndrews,AlaskaSeaLifeCenterandUAF)

Figure9:SealionpreysonsalmonatBonnevilleDamontheColumbiaRiver(USA).(Credit:USArmyCorpsofEngineers)