WIN­DOW ON THE COS­MIC DAWN

The eyes of the world are on out­back Western Aus­tralia as it pre­pares to build the most pow­er­ful ra­diote­le­scope ever con­ceived, the Square Kilome­tre Ar­ray. EL­IZ­A­BETH FINKEL re­ports.

Cosmos - - Front Page -

NEXT- GEN­ER­A­TION TELE­SCOPES usu­ally aim to dou­ble the per­for­mance of their pre­de­ces­sors. The Aus­tralian arm of SKA will de­liver a 168-fold leap on the best tech­nol­ogy avail­able to­day, to show us the uni­verse as never be­fore. It will tune into sig­nals emit­ted just a mil­lion years af­ter the Big Bang, when the uni­verse was a sea of hy­dro­gen gas, slowly per­co­lat­ing with the first gal­ax­ies. Their starlight il­lu­mi­nated the fledg­ling uni­verse in what is re­ferred to as the “cos­mic dawn”.

“It is the last non-un­der­stood event in the his­tory of the uni­verse,” says Stu­art Wyithe, a the­o­ret­i­cal as­tro­physi­cist at the Univer­sity of Mel­bourne in Aus­tralia.

Like any dream, re­al­i­sa­tion is the hard part. In 2018, when the first of 130,000 Christ­mas­tree-like an­ten­nae is de­ployed on the sandy plains of Murchi­son, an al­most un­in­hab­ited dis­trict of 50,000 square kilo­me­tres, it will mark 28 years since its con­cep­tion.

Epic bat­tles have brought the project to this point – most fa­mously the six-year con­test be­tween coun­tries to host the te­le­scope. Aus­tralia and South Africa ended up shar­ing the prize. The SKA’S te­le­scope in South Africa will be built on an­other flat, red flat plain – the Ka­roo re­gion of the North Cape. It has some­what less lofty am­bi­tions – its dishes will probe only half­way to the edge of the uni­verse. Its moniker, Ska-mid, denotes the midrange fre­quen­cies of ra­dio waves stretched across this dis­tance.

Aus­tralia’s Ska-low, by con­trast, will tune into the low fre­quen­cies em­a­nat­ing from the ex­trem­i­ties of the cos­mos. To­gether the two tele­scopes will rep­re­sent “the largest science fa­cil­ity on the planet,” says SKA di­rec­tor-gen­eral and ra­dio as­tronomer Phil Di­a­mond, who is based at Jo­drell Bank Ob­ser­va­tory in the UK.

The game-chang­ing tech­nol­ogy that will al­low us to hear the whis­pers of new­born stars against the ca­coph­ony of the uni­verse doesn’t in­volve grind­ing mir­rors to atom-thin smooth­ness or con­struct­ing dishes the size of sports fields. The dis­rup­tive tech­nol­ogy here is su­per­com­put­ing.

Once Ska-low is run­ning, it will gen­er­ate more data ev­ery day than the world’s in­ter­net traf­fic. Deal­ing with this del­uge is a chal­lenge be­ing tack­led by hefty global col­lab­o­ra­tions of academia and pri­vate en­ter­prise – and it is by no means clear how it will be solved. “It’s a scale no one has at­tempted be­fore,” says Peter Quinn, a com­pu­ta­tional as­tro­physi­cist at the Univer­sity of Western Aus­tralia, and di­rec­tor of the In­ter­na­tional Cen­tre for Ra­dioas­tron­omy Re­search (ICRAR) in Perth.

While in­ter­na­tional mega-science projects have been tack­led be­fore – think the Euro­pean Or­gan­i­sa­tion for Nu­clear Re­search (CERN), which op­er­ates the world’s largest par­ti­cle ac­cel­er­a­tor, the Large Hadron Col­lider – when it comes to the SKA, the po­ten­tial world-chang­ing spin-offs have never been so blaz­ingly ob­vi­ous.

CERN didn’t just find the Higgs bo­son – com­puter sci­en­tist Tim Bern­ers-lee cre­ated the World Wide Web to man­age its in­for­ma­tion shar­ing. Wi-fi was the spin-off when Aus­tralian CSIRO astronomers de­vel­oped ways to re­align scram­bled ra­dio sig­nals from black holes.

Mega-cor­po­ra­tions such as CISCO, Wood­side, Chevron, Rio Tinto and Google are al­ready po­si­tioned to col­lab­o­rate with SKA astronomers around the world.

A science project of this grandeur, man­aged across 10 coun­tries, in­volv­ing dozens of spe­cial­ist tech­ni­cal con­sor­tia and thou­sands of peo­ple, is chal­leng­ing enough. The ques­tion of how to divvy up the pie for con­struc­tion con­tracts and the com­mer­cial spin-offs that fol­low adds a whole new, com­pli­cated layer.

But astronomers have a great track record when it comes to teas­ing their way through gnarly col­lab­o­ra­tions to de­liver tri­umphs such as the Hub­ble Space Te­le­scope and the Ata­cama Large Ar­ray. Af­ter nearly 25 years of wran­gling, the signs are that the first bind­ing SKA treaty will be signed early next year, com­mit­ting the 10 mem­ber coun­tries – Aus­tralia, Canada, China, In­dia, Italy, New Zealand, South Africa, Swe­den, the Nether­lands and the UK – to fund­ing and con­tracts for the 2018 roll­out.

Even with the treaty, SKA will re­main a con­fus­ing beast: not one te­le­scope but two, lo­cated in two coun­tries, with head­quar­ters in a third – the UK. De­spite the name, nei­ther of the Phase 1 tele­scopes slated for con­struc­tion ac­tu­ally boasts a square kilome­tre of col­lect­ing area. That won’t be re­alised un­til Phase 2 of the project, ne­go­ti­a­tions for which have yet to be­gin.

Nev­er­the­less, as the gears of the vast project slowly grind into ac­tion, Aus­tralia is brac­ing to host its first global mega-science project. “It will be our CERN downunder,” says CSIRO as­tronomer Sarah Pearce, Aus­tralia’s science rep­re­sen­ta­tive to the SKA board. But, she adds, “don’t ex­pect a tour. It’s here pre­cisely be­cause there are very few peo­ple.” AN IDEA TAKES ROOT — The cu­ri­ous thing about as­tron­omy is that tele­scopes, as they grow more pow­er­ful, turn into time ma­chines. When Galileo peered at Jupiter, he saw it as it ap­peared some 42 min­utes ear­lier – the time it took for its light to reach him. Hub­ble’s iconic im­age of the Horse­head Ne­bula in the con­stel­la­tion of Orion is a snap­shot of how it looked 1,500 years ago.

The astronomers who con­ceived the SKA had their sights set way be­yond the 100,000-light-year di­men­sions of our own galaxy. The faint sig­nals they seek be­gan their jour­ney more than 13 bil­lion years ago, just a few mil­lion years af­ter the Big Bang.

At that point, the hot plasma of elec­trons and pro­tons had cooled enough to fuse and form the sim­plest atom – hy­dro­gen. Ex­cept for a slight rip­ple here or there, our uni­verse was a fea­ture­less sea of it. To­day, things are dif­fer­ent – the sea is dot­ted with gal­ax­ies. But how did th­ese ga­lac­tic is­lands form? To find out re­quires a te­le­scope that can look back to the rip­pling hy­dro­gen sea of 13 bil­lion years ago. “That’s why the SKA was orig­i­nally called the ‘hy­dro­gen te­le­scope’,” Quinn says.

IT WILL GEN­ER­ATE MORE DATA EV­ERY DAY THAN THE WORLD’S IN­TER­NET TRAF­FIC.

Those who imag­ined the SKA had a lust for hy­dro­gen. Their ap­petite had been whet by the Very Large Ar­ray (VLA), 27 dishes ly­ing 80km west of So­corro, in New Mex­ico.

Now known as the Jan­sky VLA, the te­le­scope gen­er­ated some of the first de­tailed maps of atomic hy­dro­gen. The bond be­tween hy­dro­gen’s elec­tron and pro­ton emits a unique 21-cen­time­tre ra­dio wave. Be­cause the uni­verse is ex­pand­ing, the waves emit­ted from outer space have stretched by the time they reach us. The futher away, the greater the stretch­ing; hy­dro­gen waves em­a­nat­ing from the edge of the uni­verse mea­sure 1.5m by the time they reach Earth. It’s known as the Dop­pler ef­fect; on Earth, we ex­pe­ri­ence it when we hear the sound of an am­bu­lance siren deepen as it speeds away, its sound wave stretch­ing as it goes.

In 1990, on the 10th an­niver­sary of the VLA, the world’s ra­dio astronomers met to cel­e­brate one of the New Mex­ico fa­cil­ity’s crown­ing achieve­ments – map­ping hy­dro­gen in nearby gal­ax­ies. Ron Ek­ers, an Aus­tralian former di­rec­tor of the ar­ray, re­calls that “ev­ery­one was on a high”.

Not con­tent to rest on their lau­rels, a small group of vi­sion­ary astronomers won­dered how far the tech­nol­ogy could be pushed. Egged on, Peter Wilkin­son from the Univer­sity of Manch­ester in Bri­tain pitched the idea of reach­ing out to gal­ax­ies at the edge of the uni­verse. A to­tal col­lect­ing area of one square kilome­tre, he fig­ured, should do the job.

The au­dac­ity of the pro­posal was amaz­ing, Quinn says: “Most te­le­scope improvements aim for a two-to-three-fold in­crease; this pro­posal rep­re­sented a 10,000-fold in­crease.” That fig­ure re­flected a 50-fold in­crease in sen­si­tiv­ity mul­ti­plied by a 200-fold in­crease in field of view. “The goal was to see a milky way at the edge of the uni­verse,” Quinn adds – and to scour the en­tire south­ern sky.

The break­through tech­nol­ogy needed to en­able this leap did not lie in fancy new te­le­scope de­signs, but in the ex­plo­sion of com­put­ing power and tech­niques able to han­dle mas­sive amounts of data.

The re­ceivers them­selves could be lit­tle more than an­ten­nas. Tuned to ra­dio wavelengths, they would pick up the ex­tra-long waves of dis­tant hy­dro­gen – co­in­ci­den­tally the same wave­length used by many FM ra­dio sta­tions. “This is where the early uni­verse is broad­cast­ing,” says Quinn. “You just can’t hear it be­cause it’s buried in the crackle.”

The more an­ten­nae, the greater the sen­si­tiv­ity – hence the planned one square kilome­tre of col­lect­ing sur­face. But the an­ten­nae don’t need to be all in one spot. In­deed, the more spread out they are, the sharper the fo­cus.

How does a for­est of ra­dio an­ten­nae fig­ure out where in the sky a sig­nal has come from? In­ter­fer­om­e­try, a tech­nique de­vel­oped by Bri­tish and Aus­tralian ra­dio astronomers in the 1940s, is the key. It re­lies on the prin­ci­ple that each an­tenna in an ar­ray re­ceives a sig­nal at a slightly dif­fer­ent time. For in­stance, ra­dio waves com­ing from the east­erly part of the sky hit the eastern-most an­ten­nae ear­lier than those ly­ing fur­ther west. By elec­tron­i­cally tweak­ing the de­lay on each, the en­tire for­est could be made to point in a par­tic­u­lar di­rec­tion of the sky.

But us­ing in­ter­fer­om­e­try to tune into sig­nals from the edge of the uni­verse would have re­quired fil­ter­ing astro­nom­i­cal amounts of data; and that was a chal­lenge yet to be mastered.

THE TUS­SLE —

In 2000, a SKA steer­ing com­mit­tee led by Ek­ers in­vited pro­pos­als for a home for the te­le­scope. Five coun­tries re­sponded. To help their bid, some built se­ri­ous pro­to­types known as “pathfind­ers”. It re­sulted in an astro­nom­i­cal bo­nanza. Aus­tralia built the ma­jes­tic dishes of the Aus­tralian Square Kilome­tre Ar­ray Pathfinder (ASKAP) and the an­tenna for­est of the Murchi­son Wide­field Ar­ray (MWA). South Africa built the seven dishes of KAT-7 and is build­ing the larger MEERKAT. China be­gan work on a pro­to­type which paved the way for the Five-hun­dred-me­tre Aper­ture Spher­i­cal ra­dio Te­le­scope (FAST), the largest sin­gle ra­dio dish in the world.

Ge­og­ra­phy worked against some of the con­tes­tants. The Chi­nese site wasn’t flat enough. The joint Brazil­ian-ar­gen­tinian bid was let down by a tur­bu­lent iono­sphere – the up­per­most layer of the at­mos­phere – which dis­torted the sought-af­ter low fre­quency ra­dio waves.

By 2006, Aus­tralia and South Africa were the last coun­tries stand­ing. Both laid claim to vast un­pop­u­lated re­gions, free of ra­dio wave in­ter­fer­ence and with rel­a­tively placid iono­spheres.

The South African site’s higher el­e­va­tion was in its favour. Aus­tralia, on the other hand, had an im­pres­sive track record in ra­dio as­tron­omy. It boasted some of the world’s first in­ter­fer­om­e­ters, built in the 1940s at Dover Heights south of Syd­ney, and the iconic CSIRO Parkes te­le­scope, op­er­at­ing since 1961.

The con­test was fierce, and for good rea­son: SKA’S ben­e­fits clearly stretched far be­yond as­tron­omy. “The de­vices and al­go­rithms de­vel­oped

AL­GO­RITHMS DE­VEL­OPED TO PUR­SUE SKA’S GOALS MAY BE THE NEXT WI- FI.

to pur­sue SKA’S goals may be the next Wi-fi, the next multi-tril­lion dol­lar tech­nol­ogy mar­ket,” says Steven Tin­gay, the former di­rec­tor of the MWA who now leads Italy’s SKA in­volve­ment. Which­ever coun­try hosted the SKA would be at the heart of the ac­tion, at­tract­ing and train­ing the next gen­er­a­tion of engi­neers and sci­en­tists in ad­vanced man­u­fac­tur­ing, telecom­mu­ni­ca­tions and high­per­for­mance com­put­ing.

Ac­com­pa­nied by the sort of me­dia at­ten­tion usu­ally re­served for a foot­ball grand fi­nal, a com­pet­i­tive and se­cre­tive bid­ding process en­sued.

In May 2012, mem­bers of the SKA or­gan­i­sa­tion voted to split the ar­ray be­tween the Aus­tralian and African sites. The South African te­le­scope would ob­serve ra­dio waves from 350 MHZ to 14 gi­ga­hertz, en­abling it to de­tect sig­nals up to six bil­lion lightyears away – a still sparse chap­ter in the uni­verse’s life story. It would use dishes like those of the JVLA, but dra­mat­i­cally in­crease speed and sen­si­tiv­ity.

Aus­tralia’s ar­ray would de­tect fre­quen­cies in the range of 50 to 350 MHZ – ideal for de­tect­ing hy­dro­gen sig­nals from the edge of the uni­verse.

Both would rely on the de­vel­op­ment of dis­rup­tive new com­pu­ta­tion tech­niques.

“We be­lieve we know how to do it, but I’m not hid­ing the fact that it’s a chal­lenge,” Di­a­mond says.

BUILD­ING IT —

Get­ting to the Aus­tralian site of the SKA gives the words “iso­la­tion” and “quiet” whole new mean­ings. First, you make your way to Perth, it­self one of the most iso­lated cities in the world. Then it’s an­other one-hour flight to the 35,000-strong port town of Ger­ald­ton. From there, bump around for four dusty hours in a four-wheel-drive un­til fi­nally, on the hori­zon, you see a suc­ces­sion of tow­er­ing white 12-me­tre te­le­scope dishes.

You have ar­rived at the Murchi­son Ra­dioas­tron­omy Ob­ser­va­tory. The 36 dishes com­prise ASKAP. De­spite the name, they are not the pro­to­type for Ska-low. That hon­our goes to the MWA, a rather less ma­jes­tic af­fair that lies hid­den in the nearby mulga scrub: 2,048 squat, wiry an­ten­nae, re­sem­bling a swarm of giant spi­ders. Un­like ASKAP, the MWA has no mov­ing parts to point to dif­fer­ent parts of the sky. That’s be­cause this is a soft­ware te­le­scope. It re­lies on a com­puter to pro­gram dif­fer­ent de­lays into the an­ten­nae so sig­nals from the same patch of sky are col­lected at the same time.

Amid great fan­fare, MWA first came on­line in mid-2013. Ac­cord­ing to di­rec­tor Ran­dall Wayth, it has blazed the trail for Ska-low. It is tuned to re­ceive sig­nals from the early uni­verse within the band­width of 60 to 250 MHZ. It does not have the sen­si­tiv­ity to de­tect fea­tures of the cos­mic dawn, but its im­pres­sive 30-de­gree field of view al­lows it to map the en­tire vis­i­ble sky over a few nights. The Ga­lac­tic and Ex­tra­galac­tic All-sky MWA (GLEAM) sur­vey, for in­stance, mapped bub­bles of ionised hy­dro­gen gas and quasars from up to six bil­lion light years away.

Two trail-blaz­ing as­pects of its op­er­a­tion are key to Ska-low. The first is that it has pi­o­neered meth­ods to ad­just for the dis­tort­ing ef­fects of the iono­sphere above Murchi­son. “It’s like try­ing to see some­thing at the bot­tom of a rip­pling pool,” ex­plains Wayth. “Luck­ily for us, it’s usu­ally just small rip­ples.”

Fil­ter­ing out the rip­ples of the iono­sphere is just one step in a mul­ti­pronged data-pro­cess­ing op­er­a­tion whose ul­ti­mate aim is to de­liver sharp im­ages of the an­cient uni­verse.

An­other early step re­duces the noise in­her­ent in the sys­tem. The heart of ev­ery ra­dio te­le­scope is an on­site com­puter known as a cor­re­la­tor. De­vel­oped through a part­ner­ship with IBM and Cisco, the MWA’S cor­re­la­tor com­pares sig­nals from each of the 2,048 an­ten­nae. Noise is ran­dom; real sig­nals are cor­re­lated. By ac­cept­ing only cor­re­lated sig­nals, this step re­duces the data to a man­age­able 1% of the ini­tial del­uge.

The next phase takes place off-site. An 800 km op­tic fi­bre fer­ries the pre-fil­tered data from the desert to the Pawsey Su­per­com­put­ing Cen­tre in Perth. A mir­ror link also takes it to col­lab­o­ra­tors at the Mas­sachusetts In­sti­tute of Tech­nol­ogy in Bos­ton, and Vic­to­ria Univer­sity of Welling­ton in New Zealand, to be used by some 35 dif­fer­ent science projects.

Just as a hu­man brain must process vast amounts of data into a mean­ing­ful rep­re­sen­ta­tion of the world, th­ese su­per­com­put­ers turn the MWA ra­dio wave sig­nals into pic­tures of the uni­verse. There are data from across dif­fer­ent re­gions of the sky, and across tens of thou­sands of fre­quen­cies. It is sifted by set­ting win­dows to ex­tract “cubes” of in­for­ma­tion. Like pix­els on a screen, they pro­vide an im­age of the uni­verse.

The MWA’S coarse res­o­lu­tion means its cubes can’t pro­duce a sharp im­age. SKA, with its 100fold greater sen­si­tiv­ity and 40-fold in­crease in res­o­lu­tion, will pro­vide more cubes to show us what is ac­tu­ally there. But in or­der to do that, it must solve the data del­uge prob­lem.

‘ WE BE­LIEVE WE KNOW HOW TO DO IT, BUT I’M NOT HID­ING THE FACT THAT IT’S A CHAL­LENGE.’

The an­tenna de­sign se­lected for SKA is not the MWA’S squat spi­der, but one that re­sem­bles a pine tree – the so-called log pe­ri­odic de­sign. Dif­fer­ent rung lengths on the tree en­able it to res­onate in a wide range of fre­quen­cies – from 50 to 650 MHZ. (MWA typ­i­cally man­ages 60 to 250 MHZ.) SKA will de­ploy 130,000 of them.

But that won’t de­liver the epony­mous square kilome­tre of col­lect­ing area. The €650 mil­lion (about US$690 mil­lion) fund­ing for phase 1 will only de­liver four-tenths of that. Nev­er­the­less, it should have the sen­si­tiv­ity to de­tect pri­mor­dial gal­ax­ies across large patches of sky.

The first phase of Ska-low will churn out raw data at a daily rate greater than the world’s in­ter­net traf­fic; im­pos­si­ble to store, or for hu­man minds to process in real time. In­ge­nious al­go­rithms will be needed to sift valu­able nuggets from the del­uge.

The Univer­sity of Cam­bridge leads a con­sor­tium of 23 or­gan­i­sa­tions, in­clud­ing Perth’s ICRAR, to de­velop new hard­ware and soft­ware sys­tems for the task. One of ICRAR’S ma­jor soft­ware con­tri­bu­tions goes by the name DALIUGE – an acro­nym for “data ac­ti­vated log­i­cal graph en­gine”. It’s also a bilin­gual play on the word del­uge: “liu” is a Chi­nese char­ac­ter mean­ing “flow”.

Last June, an ICRAR team suc­cess­fully ran the pro­to­type of DALIUGE on the sec­ond-most pow­er­ful su­per­com­puter in the world, Tianhe-2, in Guangzhou, China. Next, the team hopes to test it on the most pow­er­ful, Sun­way Tai­hu­light in Wuxi, eastern China.

The com­put­ing chal­lenges may be huge, but it’s not the first time the global com­mu­nity has taken on some­thing so big. To solve CERN’S prob­lem of dis­trib­uted pro­cess­ing and in­for­ma­tion shar­ing, its re­searchers ended up de­vel­op­ing the World Wide Web. “That changed our world for­ever,” Quinn says. “I sus­pect the SKA will do the same.”

SKA’S re­wards are al­ready reach­ing be­yond science into in­dus­try. Be­sides CISCO and IBM, other big-name col­lab­o­ra­tors on the project in­clude Bri­tish-aus­tralian min­ing giant Rio Tinto, in­ter­na­tional gas and oil com­pany Chevron, Ama­zon and In­tel. All are highly at­tuned to new ways of solv­ing their big data prob­lems – whether it is crunch­ing data to make im­ages of oil, gas and min­eral de­posits be­low the ground, or find­ing pat­terns in vast data­bases. The com­pu­ta­tional chal­lenges of the SKA are for­mi­da­ble; so too are those in­volved in build­ing and rolling out the in­fras­truc­ture in the mid­dle of the Aus­tralian out­back. It’s a per­fect job for a former army tank of­fi­cer.

Tom Booler has been project man­ager for the MWA and part of the Ska-low team since 2011. His mis­sion is to plan the con­struc­tion and de­ploy­ment of 130,000 an­ten­nas in the desert – ab­sent a lo­cal work­force, with no con­struc­tion equip­ment and no power grid. And that’s only the first phase of Ska-low. The sec­ond, slated for the mid-2020s pend­ing fund­ing, will see the num­ber of an­ten­nas swell to about a mil­lion. The scale, cost and re­mote­ness of the site make it one of the tough­est science projects ever un­der­taken.

Sup­ply­ing power is a ma­jor hur­dle. The MWA is pow­ered by a 1.6 MW hy­brid so­lar-diesel power sta­tion, parts of which must be shielded to stop the ra­dio waves it cre­ates from in­ter­fer­ing with the te­le­scope. Phase 1 of Ska-low will need 2.25 MW. Phase 2 will need the power sup­ply of a small city.

Ex­treme weather also has to be fac­tored in. In 2015, nearby Milly Milly Sta­tion bore a year’s worth of rain in five months. While cat­tle graz­ers wel­comed it, road clo­sures dis­rupted plans at the ob­ser­va­tory. Be­sides sud­den down­pours, Booler also has to reckon with tem­per­a­tures soar­ing over 40 ºc in the sum­mer months – and then there’s the desert death adder.

But one thing the shire of Murchi­son has go­ing for it – and a rea­son it won the bid for the SKA – is the quiet. Pop­u­la­tion den­sity is ex­tremely low – just 115 peo­ple spread over an area the size of the Nether­lands. There are no mo­bile phone tow­ers or ra­dio and tele­vi­sion trans­mit­ters. The shire is also hushed by reg­u­la­tions en­forced by the Aus­tralian Com­mu­ni­ca­tions and Me­dia Author­ity.

Within the ob­ser­va­tory, ev­ery ap­pli­ance gets stripped of wi-fi hard­ware be­fore it ar­rives. The ob­ser­va­tory con­trol cen­tre, which houses com­put­ers that crunch data from the ex­ist­ing tele­scopes, is the ra­dio equiv­a­lent of an air­lock, with ra­dio-wave-proof dou­ble doors and no win­dows.

In­side a ra­dius of 70km around the ob­ser­va­tory au­thor­i­ties can or­der mo­bile phones be turned off. Out to 260km emis­sions are reg­u­lated in key ra­dio fre­quency ranges.

The en­tire area is more than six times big­ger than the US Na­tional Ra­dio Quiet Zone, home to the Green Bank ra­dio te­le­scope and a pop­u­la­tion run­ning into hun­dreds of thou­sands.

THE WORLD WIDE WEB DE­VEL­OPED BY CERN CHANGED THE WORLD FOR­EVER. ‘ I SUS­PECT THE SKA WILL DO THE SAME.’

The quiet zones do not ex­tend to high al­ti­tudes, so planes com­mu­ni­cat­ing with air traf­fic con­trol could present a prob­lem. To tackle that is­sue, CSIRO re­searchers have be­gun to in­ves­ti­gate ways to mea­sure the in­ter­fer­ence and re­move it from the te­le­scope ob­ser­va­tions.

FI­NAL STRETCH —

As dif­fi­cult as build­ing the SKA will be, com­ing up with the money to bankroll it is trick­ier. Ne­go­ti­a­tions with the 10 par­tic­i­pat­ing gov­ern­ments for the first phase have been un­der­way since late 2015.

But there’s a new sense of ease per­vad­ing the SKA com­mu­nity as it looks to an April 2017 sign-off on a bind­ing treaty known as an In­ter­na­tional Gov­ern­ment Or­gan­i­sa­tion (IGO). Once signed, min­is­ters of each coun­try will have a year to rat­ify it.

Once rat­i­fied, re­searchers are con­fi­dent things should roll out smoothly. There is a strong prece­dent: CERN is gov­erned by an IGO, with 22 mem­ber states. “It’s a well-tested model,” says Pearce, who pre­vi­ously worked on com­put­ing chal­lenges for the LHC as part of a multi­na­tional col­lab­o­ra­tion.

With Ska-low ex­pected to come on­line in 2021, and be fully op­er­a­tional in 2024 astronomers are at last al­low­ing them­selves to get ex­cited. “Un­til we can put a ra­dio te­le­scope on the moon, it will be the great­est ad­vance in low-fre­quency ra­dio as­tron­omy,” says Elis­a­beth Mills, a ra­dio as­tronomer at San José State Univer­sity in Cal­i­for­nia. “With such a great leap in tech­ni­cal ca­pa­bil­i­ties, the most im­por­tant ad­vances from this te­le­scope may be in ar­eas we can­not even cur­rently pre­dict or imag­ine.”

EL­IZ­A­BETH FINKEL is the ed­i­tor-in-chief of Cos­mos mag­a­zine.

IM­AGES 01 Dragon­fly Me­dia / CSIRO 02 SKA Or­gan­i­sa­tion / Eye Candy An­i­ma­tion 03 SKA Or­gan­i­sa­tion / Eye Candy An­i­ma­tion 04 MWA / Hur­ley-walker et al. (2016) 05 Pawsey Su­per­com­put­ing Cen­tre

IL­LUS­TRA­TIONS An­thony Calvert

‘ THE MOST IM­POR­TANT AD­VANCES MAY BE IN AR­EAS WE CAN­NOT EVEN IMAG­INE.’

02 The 200 dishes of Ska-mid to be rolled out in South Africa will probe half way to the edge of the uni­verse. (Artist’s im­pres­sion)

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