* Astronomy

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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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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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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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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