Ra­dio waves from deep space baf­fle sci­en­tists

The Phnom Penh Post - - WORLD -

ASTRONOMERS in Canada have de­tected a mys­te­ri­ous vol­ley of ra­dio waves from far out­side our gal­axy, ac­cord­ing to two stud­ies pub­lished on Wednesday in Na­ture.

What corner of the uni­verse these pow­er­ful waves come from and the forces that pro­duced them re­main un­known.

The so-called re­peat­ing fast ra­dio bursts were iden­ti­fied dur­ing the trial run last sum­mer of a built-for-pur­pose tele­scope run­ning at only a frac­tion of its ca­pac­ity.

Cana­dian Hy­dro­gen In­ten­sity Map­ping Ex­per­i­ment, known by its acro­nym Chime, the world’s most pow­er­ful ra­dio tele­scope – spread across an area as big as a foot­ball pitch – is poised to de­tect many more of the enig­matic pulses now that it is fully op­er­a­tional.

“At the end of the year, we may have found 1,000 bursts,” said Deb­o­rah Good, a PhD stu­dent at the Univer­sity of Bri­tish Columbia and one of 50 sci­en­tists from five in­sti­tu­tions in­volved in the re­search.

Fast ra­dio bursts (FRBs) flash only for a mi­cro-in­stant, but can emit as much en­ergy as the Sun does in 10,000 years.

Ex­actly what causes these high-en­ergy surges of long waves at the far end of the elec­tro­mag­netic spec­trum re­mains the sub­ject of in­tense de­bate.

More than 60 bursts have been cat­a­logued since 2007, but only one other – ob­served in 2012 at the Arecibo Ob­ser­va­tory in Puerto Rico – was a re­peater.

“FRBs, it seems, are likely gen­er­ated in dense, tur­bu­lent re­gions of host gal­ax­ies,” said Shri­harsh Ten­dulkar, a cor­re­spond­ing au­thor for both stud­ies and an as­tronomer at McGill Univer­sity.

Cos­mic con­vul­sions cre­ated by the tur­bu­lent gas clouds that give rise to stars, or stel­lar ex­plo­sions such as su­per­novae, are both pos­si­ble in­cu­ba­tors.

But con­sec­u­tive ra­dio bursts are a spe­cial case.

“The fact that the bursts are re­peated rules out any cat­a­clysmic mod­els in which the source is de­stroyed while gen­er­at­ing the burst,” Ten­dulkar said. “An FRB emit­ted from a merger of two neu­tron stars, or a neu­tron star and a black hole, for ex­am­ple, can­not re­peat.”

It is not yet clear whether the breed­ing grounds of re­peat­ing bursts are dif­fer­ent from those that pro­duce only a sin­gle ra­dio pulse. Sig­nif­i­cantly, the 2012 and 2018 “re­peaters” have strik­ingly sim­i­lar prop­er­ties.

Chime also spot­ted a dozen sin­gle burst ra­dio waves, but with an un­usual pro­file.

Most FRBs spot­ted so far have wave- lengths of a few cen­time­tres, but these had in­ter­vals of nearly a me­tre, open­ing up a whole new line of in­quiry for astronomers.

Could these enig­matic ra­dio pulses point to in­tel­li­gence else­where in the Uni­verse? Might they be mes­sages in a bot­tle?

“It is ex­tremely, ex­tremely un­likely,” said Ten­dulkar. “As a sci­en­tist I can’t rule it out 100 per cent. But in­tel­li­gent life is not on the minds of any as­tronomer as a source of these FRBs.”

Con­structed in Bri­tish Columbia, Chime is com­posed of four, 100m-long half-pipe cylin­ders of metal mesh which re­con­struct im­ages of the sky by pro­cess­ing the ra­dio sig­nals recorded by more than a thou­sand an­ten­nas.

“This sig­nal pro­cess­ing sys­tem is the largest of any tele­scope on Earth,” the re­searchers said.

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