BBC Focus - 04.2020_

HUBBLE’S HIDDEN GEMS FEATURE

HOT STUFF

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NGC 5033

SpiralgalaxyNGC 5033 is much
likeourown.It’saroundthesame
size,about100,000light-years
across,andatitscoreis a super-
massiveblackhole,weighing
anywherebetween 10 millionanda
fewbillionsolarmasses.
UnliketheMilkyWay,however,
NGC5033’sblackholeisn’tdocile.
Instead,it’ssurroundedbya
swirlingdiskof gasanddust,
movingsorapidlythatit
superheats.Thismakesit glow
brightly,formingwhat’sknownas
anactivegalacticnucleus.
Overtheyears,Hubblehasfound
hundredsof supermassiveblack
holesbylookingat themotionof
dustinthecentresof galaxies.If the
materialis movingrapidly,there
mustbea blackholeholdingit in
placeorit wouldspeedoffintothe
restof thegalaxy.
“Hubbleobservationsof the
centresof massivegalaxiesshowed
thatsupermassiveblackholeslived
inthecentresof almostevery
galaxy,”saysLotz.“Wenow
believethatsupermassiveblack
holesplaya critical role in shaping
galaxies.”

THE LONELY STAR

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FOMALHAUT

BeforeHubblelaunched,theonlyplanetsweknew

aboutwerethoseinourSolarSystem.Today,we

knowof thousandsof exoplanetsorbitingotherstars.

“Hubblehasbeenrightat theforefrontof studying

exoplanets,”saysWiseman.“It’snota great

instrumentforfindingthem– thefieldof viewis too

smallandit onlyhasa smallwindowforsearching

thevastsky– butwhatit canbeusedto do,is carry

outintimatelydetailedfollow-upobservations.”

OnerarecasewhereHubbledidfinda planetwas

aroundthestarFomalhaut.Thestaris surroundedby

a ringof duststretchingoutto around 20 billion

kilometres– that’sthreetimesfurtheroutthanPluto.

Suchringsareusuallycreatedbyplanets

shepherdingdustintoa specificorbit.Hopingto track

downthisworld,Hubblerepeatedlytookimagesof

thesystemovera periodof severalyears.Comparing

theimages,astronomersfounda brightdotslowly

movingaroundthedisk.It wasa planet,andthe first

one ever directly imaged in visible light. 2