The next supernova
theratewouldkeepincreasinguntiltheexplosion,”
saysJha.However,asthenextgenerationof
neutrinodetectorsarebeingbuilt,researchintothe
plausibilityofa neutrino-basedsupernovaeearly
warningsystemhasthrownupsomechallenges,
saysFields.“Ifaneventisdetectedina single
detector,littletonoinformationaboutitsoriginwill
beincludedinthesignal.”Whilepre-supernovae
physicsmighthavetorelyonsimulationsfora
whilelonger,theobservationaldatawewillget
fromthenextnearbysupernovawillkeepscientists
busyforyearsanddecadestocome.Itwillbea
tantalisingwait.
Wide-fieldarrayssuchastheAll-SkyAutomated
SurveyforSupernovae,featuringa globalnetwork
of 20 robotictelescopes,couldhelppinpointthe
source,andmayevenspotthefirsthintsofsurface
change.Inotherwavelengthsyouhavesurveys
capturinghigh-energycosmicrayssuchasIceCube,
whilespacetelescopeslikeFermi,IntegralandSwift
canrecordeventsinX-raysandgammarays.All
ofthesearealreadycontributingsignificantlytoarapidlygrowingrecordofsupernovaeeventsfurther
afield.Inthefirstthreeweeksof 2020 theTransient
NameServer,wheretheastronomycommunitylogs
theirobservations,added 983 newevents,ofwhich
68 havebeenconfirmedassupernovae.
AtStanway’sUniversityofWarwick,the
Gravitational-waveOpticalTransientObserver
projectislookingoutforgravitationalwavesthat
accompanylargesupernovaeevents.InJanuary
Betelgeusehittheheadlinesfora secondtimeafter
thedetectionofexactlythistypeofwave,coming
fromthedirectionofOrion.Thelinkhassincebeen
dismissed,butit’sexactlywhat’sexpectedifthered
supergiantentersitsfinalphase.“Itgotmescared,”
saysGuinan,whoadmitstoimmediatelyrunning
outsidetocheckonthestar.
Sowherewillthenextsupernovaetakeplace?On
a universalscale,severalwillhavegoneoffacross
thecosmosbythetimeyoufinishthissentence.
Intermsofourimmediategalacticneighbourhood,
severalneweventsareconfirmedeachday,though
it’sveryunlikelythenextone,oreventhenextfew
dozen,willmakeripplesbeyondtheastronomy
community.“Themostlikelyscenarioisthatthe
nextnearbyeventwillcomefromanobscure
starwhichdoesn’tevenhavea nameoutsideof
scientificcatalogues,“saysStanway.
Ifwearetalkingaboutthenextsupernovathat
willlightupournightskiesandstoppeoplein
thestreet,thenBetelgeuseandtheprogenitors
monitoredbyGuinanarecertainlygoodbets.He,
forone,iskeepingfingerscrossed.“Itcouldbe
tonight.Itcouldbea hundredthousandyearsfrom
now.I wouldpreferittobenow.I’mgettingold.It
wouldbegreattoseeit.”five stars
ready to
explode
Bottomleft:
Supernova
1987awasthe
lastsupernova
thatwas
visibletothe
nakedeyeBetelgeuse vs
the Solar System
Initscurrentredsupergiant
phaseBetelgeusehasa
diameterofjustovera
billionkilometres,whichis
900 timesthatofourSun.Betelgeuseissolargethatifweplace
itintheSun’sexactspotinourSolar
System,alltherockyinnerplanets–
andperhapsevenJupiter– wouldbe
orbitinginsideitsatmosphere.Betelgeuseisexpectedto
haveanabsolutemagnitude
of-16or-17whenitblowsup.
Whenyoucalculatehowfar
awayitis,thiswouldmakeit
asbrightasthefullMoon.Betelgeuse
Stellar evolution
models suggest
it should go
supernova
anytime in the
next100,000
years,whenitwillbe
asbrightasthefullMoonin
thenightsky.Evenbeforeits
recentdimmingBetelgeuse
showedthemostvariationof
anyprogenitors.Antares
Theredeyeof
thescorpionin
theconstellation
Scorpiusisdue
togosupernova
inthenextmillion
years.Witha mass 15 to
18 timesthatofourSun,itwill
bespectacular,thoughitslack
ofvariabilitysuggestsit’snot
quitereadyyet.MuCephei
Knownas
‘Herschel’s
Garnet’,it’s
furtherawaythan
Betelgeuse,but
doubleitsdiameter,and
thereforeperhapscloserto
death.Itssupernovawould
likelyproducea blackhole
whileprovidinga ‘gueststar’
asbrightasVenus.EtaCarinae
Observershave
alreadyseenthis
binarystarthrow
outitsoutermost
layersina seriesof
pulses.Muchfurther
awaythanBetelgeuse,
itsimpendingdeathcould
producea gamma-rayburstor
a superluminoussupernova,
easilyvisiblefromEarth.VSagittae
Madeupofan
ordinarystar
spirallingin
towardsa
whitedwarf,
researchershave
predicteda date
laterinthiscenturyfor
a supernovaeventthatwill
createa ‘newstar’asbrightas
Siriusinthenightsky.
© ESO
© Getty
© ESA© ESA© NASA/ESA© NASA© ESO