The Economist - UK (2019-06-01)

74 Science & technology The EconomistJune 1st 2019

2 DrSundaramcitesasananalogytheex-

ampleofcomputervision.This,hesays,

hasimprovedquicklyinrecentyearsbe-

causealmosteveryonehaseasyaccesstoa

standardised,cheapdigitalrecordingde-

vice,thecamera,theoutputsofwhichare

easytoshare,labelandprocessbycomput-

ers.Theanalogyisnotperfect.Peoplelike

taking and sharing photographs, so the

supplyisendlessandfree.Theywillhave,

bycontrast,tobeencouraged,andperhaps

paid,tohandlethingswhilewearingspe-

cialgloves,howeverinexpensive.Butthe

successofso-called citizen sciencepro-

jects,whichrequirethemassparticipation

ofinterestedamateurs,suggeststhetask

wouldnotbeimpossible.Soif,inthefu-

ture,someoneasksyoutoputona newpair

ofglovesandhandlea strangeobject,don’t

takeit thewrongway. 7

T

was quitea show:a trainofilluminat-

eddotsmovingacrossthesky,manyof

themasbrightasPolaris,thenorthstar.

Thesewerenotnewastronomicalobjects,

however. Rather, they were the first

trancheofsatellitesforStarlink,a project

intendedtoprovideinternetaccessacross

theglobe.Thesewerelaunchedintoorbit

onMay24thbySpaceX,anAmericanrock-

etryfirm.

Seeingsatellitesfromthegroundwith

thenakedeyeisnothingnew.Butastrono-

mers(professionalandamateur)weresur-

prised,andunhappy,atjusthowmanyand

howbrighttheStarlinksatellitesappeared

tobe.Quitea fewofthemtooktoTwitterto

raisethealarmandpostpicturesandvid-

eosoftheblazingbirds.Theirworrywas

thatthesesatellitesandtheirsuccessors

couldchangethenightskyforever.Ifthe

initial 60 membersoftheStarlinknetwork

werealreadycausingnoticeablelightpol-

lution,theyreasoned,howbadwouldit get

oncethefullconstellationof12,000had

beenlaunched?

Forthosewhoenjoywatchingthenight

skyforpleasureitwouldsurelybesad,for

itwouldmorethantriplethenumberof

man-madeobjectsinthefirmamentand

thusfurtherdegradethenaturalbeautyof

theheavens—abeautyalreadydiminished

inmanyplacesbylightpollutionfromthe

ground.Forthoseinvolvedininvestigating

theuniversescientifically,though,itmay

bemorethanmerelysad.Insomecasesit

couldbejob-threatening.

Preliminaryanalysisshows,forexam-

ple,thatalmosteveryimagefromtheLarge

SynopticSurveyTelescopeinChile,cur-

rentlynearingcompletionandintendedto

photographtheentireavailableskyevery

fewnightswhenitisoperational,could

containa satellitetrail.Thesecanbeedited

out,buteachcorrectiondestroysvaluable

data.Itispossiblethatsomeexperiments,

suchasregularlytimedobservationsofthe

variationinbehaviourofastronomicalob-

jects,willnolongerbefeasible.

Opticalastronomersthushavecauseto

benervousaboutStarlink.Forradioas-

tronomersitsimpactmaybeevenmorese-

rious.The satellites’mode of operation

necessarilyrequiresthem to sendradio

signalsbacktoEarth,allofwhichwillbe

stronger than any signal arriving from

deepspace.Thiscanbeaccommodatedtoa

certainextentbyknowingwhichfrequen-

ciesthesatellitesarebroadcastingon,and

adjusting accordingly. But exactly how

badlyradioobservatoriesareaffectedwill

dependonhowwellthesatellitesmanage

toconfinetheirbroadcastswithinthose

frequencies, which remains to be seen.

Elon Musk, SpaceX’s boss, initially dis-

missed astronomers’ concerns, tweeting at

the weekend that there were “already 4,900

satellites in orbit, which people notice

~0% of the time. Starlink won’t be seen by

anyone unless looking very carefully & will

have ~0% impact on advancements in as-

tronomy.” In later exchanges, though, he

struck a more understanding tone. Starlink

would avoid the frequencies associated

with radio astronomy, he said, and if the

satellites’ orientations needed to be

tweaked to minimise solar reflection dur-

ing critical astronomical experiments, that

could easily be done. Moreover, as the ini-

tial Starlink satellites moved into their op-

erational configuration after the weekend,

their brightness dropped—though they

still occasionally flared as they crossed the

sky,probablybecauseofreflectionsfrom

theirlargesolarpanels.

MrMuskalsoseemed,inhistweets,to

suggest that the aims of Starlink out-

weighedtheharms.“Potentiallyhelping

billions of economically disadvantaged

peopleisthegreatergood.Thatsaid,we’ll

makesureStarlinkhasnomaterialeffect

on discoveriesin astronomy.We care a

greatdealaboutscience.”Hisassertionhas

merit. The problem, as MarkMcCaugh-

rean,senioradviserforscienceandexplo-

rationattheEuropeanSpaceAgency,ob-

serves,isthattherehasbeenlittlepublic

discussionofthematter.Fromhispointof

viewthenightskyisapubliccommons

that risksappropriationin thenameof

privateinterest.Whetherthatappropria-

tionservesthegreatergoodshouldatleast

bea matterofdebate.

Fornow,astronomersplantocarryout

furthersimulations ofthepotentialim-

pacts ofStarlinkand othercommunica-

tion-satellitenetworksplannedbycompa-

niessuchasOneWeb.Butevenwhenthat

workiscomplete,itisunclearwhatthey

can actuallydo to makeSpaceX and its

competitorslistento theirconcerns,for

thereisnolegislationtoregulatetheim-

pactofsatellitesonthenightsky.

America’s Federal Communications

Commissiondoesconcernitselfwithhow

satellitesusetheavailableradiospectrum

andwithwhathappenstothemafterthey

havedonetheirjob.Butthatisit.Withthe

comingmega-constellationsofcommuni-

cationssatellites,it isperhapstimeforthis

tochange,andforgovernments(notonly

America’s) to involve themselves more

deeplyintheusesofheaven. 7

Theunexpectedbrightnessofnewsatellitescouldruinthenightsky

Satellites versus astronomers

Blinded by the light

Starlinkreadytolaunch

Awards:Two of The Economist’s journalists carried

off laurels at this year’s Association of British

Science Writers awards ceremony, held in London

on May 28th. Catherine Brahic was pronounced one

of two Science Journalists of the Year. Hal Hodson

won the prize for Feature of the Year, for “The

network within, the network without”, about a boy

who is missing part of his brain.

’