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Einstein's theory of general relativity seen in action by astronomers

Astronomers measured bursts of energy from a neutron star which is being orbited by a white dwarf star. The gravity created by the neutron star, which is a super dense spinning pulsar, created a wrinkle in the fabric of space time in a way predicted by Einstein in his famous theory in 1915.
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Chiral gravitons
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Title: A Sinister Universe: Chiral gravitons lurking, and Lyth un-bound
Authors: Peter Adshead, Emil Martinec, Mark Wyman

Models of inflation involving non-Abelian gauge field backgrounds can produce gravitational waves at an observable level with a preferred handedness, while satisfying current observational bounds. This asymmetry comes about because the non-Abelian background generates parity-violation in the action for perturbations. In the specific model we study, Chromo-Natural Inflation, these gravitational waves can be produced at observable levels even when no field makes a super-Planckian field excursion, thus evading a common formulation of the Lyth bound.

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Chinese scientists find evidence for speed of gravity

Chinese scientists revealed Wednesday that they have found evidence supporting the hypothesis that gravity travels at the speed of light based on data gleaned from observing Earth tides.
Scientists have been trying to measure the speed of gravity for years through experiments and observations, but few have found valid methods.

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Spacetime ripples from dying black holes could help reveal how they formed

Researchers from Cardiff University have discovered a new property of black holes: their dying tones could reveal the cosmic crash that produced them.
Black holes are regions of space where gravity is so strong that not even light can escape and so isolated black holes are truly dark objects and don't emit any form of radiation.
However, black holes that get deformed, because of other black holes or stars crashing into them, are known to emit a new sort of radiation, called gravitational waves, which Einstein predicted nearly a hundred years ago.

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Gravitational Waves
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Space-Warping White Dwarfs Produce Gravitational Waves

Gravitational waves, much like the recently discovered Higgs boson, are notoriously difficult to observe. Scientists first detected these ripples in the fabric of space-time indirectly, using radio signals from a pulsar-neutron star binary system. The find, which required exquisitely accurate timing of the radio signals, garnered its discoverers a Nobel Prize. Now a team of astronomers has detected the same effect at optical wavelengths, in light from a pair of eclipsing white dwarf stars.
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Scientist pins hope on new evidence for universe's origin

Scientists believe that inflation, if it actually occurred, could have created gravitational waves, which are ripples in the curvature of space-time.

"People have conducted many experiments to detect them, but nobody, no matter what means are applied, has ever detected a gravitational wave at all, Now we have found a different way of detecting them. Gravitational waves would have caused cosmic background radiation -- the remnant light from the very early universe -- to be polarised in a particular pattern. We know how to measure the polarisation" - Charles Bennett.

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Title: Gravitational Wave Astronomy: Needle in a Haystack
Authors: Neil J. Cornish

A world-wide array of highly sensitive interferometers stands poised to usher in a new era in astronomy with the first direct detection of gravitational waves. The data from these instruments will provide a unique perspective on extreme astrophysical phenomena such as neutron stars and black holes, and will allow us to test Einstein's theory of gravity in the strong field, dynamical regime. To fully realise these goals we need to solve some challenging problems in signal processing and inference, such as finding rare and weak signals that are buried in non-stationary and non-Gaussian instrument noise, dealing with high-dimensional model spaces, and locating what are often extremely tight concentrations of posterior mass within the prior volume. Gravitational wave detection using space based detectors and Pulsar Timing Arrays bring with them the additional challenge of having to isolate individual signals that overlap one another in both time and frequency. Promising solutions to these problems will be discussed, along with some of the challenges that remain.

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Gravitational waves
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Gravitational waves that are 'sounds of universe'

Just as sound complements vision in our daily life, gravitational waves will complement our view of the universe taken by standard telescopes.
Albert Einstein predicted gravitational waves in 1918. Today, almost 100 years later, advanced gravitational wave detectors are being constructed in the US, Europe, Japan and Australia to search for them. While any motion produces gravitational waves, a signal loud enough to be detected requires the motion of huge masses at extreme velocities. The prime candidate sources are mergers of two neutron stars: two bodies, each with a mass comparable to the mass of our sun, spiralling around each other and merging at a velocity close to the speed of light.
Such events are rare, and take place once per hundreds of thousands of years per galaxy. Hence, to detect a signal within our lifetime the detectors must be sensitive enough to detect signals out to distances of a billion light years away from Earth. This poses an immense technological challenge. At such distances, the gravitational waves signal would sound like a faint knock on our door when a TV set is turned on and a phone rings at the same time.

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European scientists take a major step forward towards detecting gravitational waves

Scientists operating Europe's gravitational wave observatories have combined efforts this summer to search for gravitational waves. This groundbreaking research is being taken forward in Europe while similar US-based detectors undergo major upgrade work.
Cataclysmic cosmic events such as supernovae, colliding neutron stars and black holes, as well as more familiar objects such as rotating neutron stars (pulsars) are expected to emit gravitational waves - oscillations in the fabric of space-time predicted by Einstein's Theory of General Relativity. The detection of such waves would revolutionise our understanding of the universe.

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Title: Detection With Matter-wave Interferometers Based On Standing Light Waves
Authors: Dongfeng Gao, Peng Ju, Baocheng Zhang, Mingsheng Zhan

We study the possibility of detecting gravitational-waves with matter-wave interferometers, where atom beams are split, deflected and recombined totally by standing light waves. Our calculation shows that the phase shift is dominated by terms proportional to the time derivative of the gravitational wave amplitude. Taking into account future improvements on current technologies, it is promising to build a matter-wave interferometer detector with desired sensitivity.

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