Fresh con­fir­ma­tion of Ein­stein’s the­ory

Weekend Argus (Saturday Edition) - - FRONT PAGE - IRENE KLOTZ

CAPE CANAVERAL: SCI­EN­TISTS have for a third time de­tected rip­ples in space from black holes that crashed to­gether bil­lions of light years from Earth

The dis­cov­ery con­firms a new tech­nique for ob­serv­ing cat­a­clysmic events in the uni­verse, re­search pub­lished on Thurs­day shows.

Such vi­bra­tions, known as grav­i­ta­tional waves, were pre­dicted by Al­bert Ein­stein more than 100 years ago and were de­tected for the first time in Septem­ber 2015. They are trig­gered by mas­sive ce­les­tial ob­jects that crash and merge, set­ting off rip­ples through space and across time.

The lat­est de­tec­tion oc­curred on Jan­uary 4. Twin lasers in Louisiana and Wash­ing­ton in the US picked up the faint vi­bra­tions of two black holes 20 and 30 times more mas­sive than the sun re­spec­tively be­fore they spi­ralled to­ward each other and merged into a larger black hole.

The dis­cov­ery marks a turn­ing point in the nascent field of grav­i­ta­tional-wave as­tron­omy, which sci­en­tists are de­vel­op­ing to learn more about how the uni­verse formed.

The first de­tec­tion of grav­i­ta­tional waves cre­ated a sci­en­tific sen­sa­tion.

“We’re re­ally mov­ing from nov­elty to a new ob­ser­va­tional sci­ence,” said Mas­sachusetts In­sti­tute of Tech­nol­ogy as­tro­physi­cist David Shoe­maker.

A team of more than 1 000 sci­en­tists pub­lished their find­ings in this week’s is­sue of Phys­i­cal Re­view Letters.

Like the pre­vi­ous two de­tec­tions, the grav­i­ta­tional waves dis­cov­ered in Jan­uary slightly jig­gled the L-shaped, 4km laser beams at the heart of the Laser In­ter­fer­om­e­ter Grav­i­ta­tional-Wave Ob­ser­va­tory or Ligo.

By match­ing the shape of the waves with com­puter mod­els, sci­en­tists con­firmed the col­li­sion took place about 3 bil­lion light years from Earth, which is twice as far as pre­vi­ous de­tec­tions.

Black holes are re­gions so dense with mat­ter that not even pho­tons of light can es­cape their grav­i­ta­tional pull.

Anal­y­sis shows the pair prob­a­bly were spin­ning in dif­fer­ent di­rec­tions be­fore merg­ing, a clue that they formed sep­a­rately in a dense clus­ter of stars, sank to the core of the clus­ter and then paired up, said Ge­or­gia In­sti­tute of Tech­nol­ogy physi­cist Laura Cado­nati.

A sec­ond grav­i­ta­tional wave ob­ser­va­tory in Italy is sched­uled to be­gin op­er­a­tions soon and will en­hance Ligo’s stud­ies. Sci­en­tists even­tu­ally ex­pect to be able to find black holes merg­ing about once a day.

They also are on the hunt for other ob­jects, in­clud­ing col­lid­ing neu­tron stars, the dense rem­nants of col­lapsed stars so packed with mat­ter a sin­gle tea­spoon would weigh 10 mil­lion tons on Earth. – Reuters

PIC­TURE: WWW.TEACHASTRONOMY.COM

Re­searchers have dis­cov­ered rip­ples trig­gered by black holes crash­ing and merg­ing, first de­scribed by Al­bert Ein­stein.

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