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Astronomers detect more of Einstein's ripples in space

02 Juin 2017

LIGO changed that. a year ago the collaboration announced that its twin detectors had picked up a passing distortion in late 2015 caused by two black holes crashing into one another. When the black holes coalesce, the total rotational velocity of the merged black hole can not exceed a certain upper limit. Another will be LIGO India, a collaboration with Indian scientists to create a third point in the LIGO system, now planned to commence operation in 2024. Such an astronomy would combine gravitational-wave observations with electromagnetic-wave observations, such as those from traditional optical telescopes, to allow new insights in astrophysics and cosmology.

In all three discoveries, LIGO detected gravitational waves from the energetic mergers of black hole pairs. The newly formed black hole had a mass about 50 times that of our Sun, and the collision produced more power than is radiated as light by all the stars in the universe at any given time.

Some 3 billion light years away in space, two black holes merged into one with a mass about 48 times that of the sun.

One current problem in making those ties, the scientists noted, is that, while LIGO is able to reach increasingly far into space to suss out gravitational waves, it now has very little information on just where in the sky those waves are coming from. It could be the remnants of "primordial" black holes created at the beginning of the universe.

"The most exciting thing for me is how loud and clear this latest gravitational wave was", Lovelace said.

"Although our measurement can not precisely determine if the black holes were tilted, we have indication that at least one of the two black holes was misaligned, which favors the first theory", said Cadonati.

Scientists will now be able to delve deeper back into time and peer inside some of the biggest objects in the universe, such as the earliest moments after the Big Bang, Ms Sun says. "And we're learning more - we're learning where we're coming from, and that's the big excitement".

The astronomers believe their latest finding "provides clues about the directions in which the black holes are spinning".

This view has revealed that the black holes in this new event are not spinning in the same direction as they orbit each other.

Researchers are also starting to piece together the story of how black holes actually do collide, whether they start off as huge stars not far from one another or are black holes in a tight pair. "If we can detect more systems, we can nail down under what circumstances black holes formed and evolved to form binary systems that ultimately merged". Then, the machine was shut down for repairs and improvements.

In the other theory, the black holes come together within crowded stellar clusters. In one model, the black holes come together later in life within crowded stellar clusters, pairing up after they sink to the center of a star cluster.

But the most recent LIGO data suggest that the former black holes have spins that aren't quite aligned.

When it comes to black holes, the universe is a bit like a two-year-old. LIGO found hints that at least one black hole in the system called GW170104 was non-aligned with its orbital motion before it merged with its partner. The second theory suggests that the black holes form independently within dense clusters of stars. Various processes could contribute to the formation of black hole pairs, Berti says.

And even those instruments need a helping hand, in the form of signals produced by the most powerful of astrophysical phenomena. "And I want it to be a signal that no one has predicted, and for which no one has an explanation".

LIGO consists of two facilities: one in Hanford, Washington and one in Livingston, Louisiana. The fact that this third merger happened at a distance of about 3 billion light-years gave scientists a chance to test yet another of Einstein's hypotheses.

If we think of spacetime as a massive pond, gravitational waves are the ripples that move across it when a stone is thrown in.

"In Einstein's theory, no such dispersion is expected", said Sathyaprakash.

"GW170104 is half as bright as the first discoveries, but even at that distance it did not lose energy", he said.

Scientists from the LIGO and Virgo collaboration detected the astronomical event known as GW170104 on January 4, 2017.

"When an optical source potentially related to the LIGO event was discovered, the CZTI team joined hands with the worldwide GROWTH collaboration to study it".

Scientists will continue to search the latest LIGO data for signs of space-time ripples from the far reaches of the cosmos. Jo van den Brand, the Virgo Collaboration spokesperson, said they expect Virgo to expand the network of detectors by this summer. With three detectors, we'll get much better placement of the events that generated them.

"It's like if the economics you run to make sure your own family deals with money properly would work for the economy of the US", Vitale said. The colored bands are gravitational-wave peaks and troughs, with the colors getting brighter as the wave amplitude increases. But physicists (and Einstein himself) have long speculated that the theory isn't complete, as it doesn't play well with the laws of quantum mechanics.

"It looks like Einstein was right - even for this new event, which is about two times farther away than our first detection", says LIGO physicist Laura Cadonati of Georgia Tech. By combining results from multiple LIGO events, more precise constraints on deviations from the predictions of Einstein's theory were obtained.

Astronomers detect more of Einstein's ripples in space