Posts Tagged ‘gravity waves’

A Large Step Closer To The First Direct Detection Of Gravitational Waves

On May 19, the LIGO Scientific Collaboration (LSC) will dedicate their second-generation gravitational-wave detectors (aLIGO) in a ceremony at the Hanford detector site. Researchers at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Hannover and Potsdam, Germany, have made significant contributions in several key areas: custom-made high-power laser systems required for the high-precision measurements, efficient data analysis methods running on powerful computer clusters, and accurate waveform models to detect gravitational waves and extract astrophysical information. The AEI is a leading partner in the international gravitational-wave science community, and its researchers keep pushing the boundaries of science on the way to the first direct detection of gravitational waves.

This will open a new window to the otherwise invisible “dark” side of the Universe and mark the beginning of gravitational-wave astronomy. Gravitational waves are ripples in space-time that are emitted by cataclysmic cosmic events such as exploding stars, merging black holes and/or neutron stars, and rapidly rotating compact stellar remnants. These waves were predicted in 1916 by Albert Einstein as a consequence of his general theory of relativity, but have never been observed directly. At their design sensitivity, the aLIGO instruments should detect multiple gravitational-wave events each year.

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Planck: Gravitational Waves Remain Elusive

February 2, 2015 Leave a comment

Cosmic Microwave Background seen by Planck. Credit: ESA and the Planck Collaboration

Cosmic Microwave Background seen by Planck. Credit: ESA and the Planck Collaboration

Despite earlier reports of a possible detection, a joint analysis of data from ESA’s Planck satellite and the ground-based BICEP2 and Keck Array experiments has found no conclusive evidence of primordial gravitational waves.

The Universe began about 13.8 billion years ago and evolved from an extremely hot, dense and uniform state to the rich and complex cosmos of galaxies, stars and planets we see today.

An extraordinary source of information about the Universe’s history is the Cosmic Microwave Background, or CMB, the legacy of light emitted only 380 000 years after the Big Bang.

ESA’s Planck satellite observed this background across the whole sky with unprecedented accuracy, and a broad variety of new findings about the early Universe has already been revealed over the past two years.

But astronomers are still digging ever deeper in the hope of exploring even further back in time: they are searching for a particular signature of cosmic ‘inflation’ – a very brief accelerated expansion that, according to current theory, the Universe experienced when it was only the tiniest fraction of a second old.

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First Direct Evidence Of Inflation And Primordial Gravitational Waves

Credit: The BICEP2 Collaboration

Credit: The BICEP2 Collaboration

Astronomers announced today that they have acquired the first direct evidence that gravitational waves rippled through our infant universe during an explosive period of growth called inflation. This is the strongest confirmation yet of cosmic inflation theories, which say the universe expanded by 100 trillion trillion times in less than the blink of an eye.

“The implications for this detection stagger the mind,” says Jamie Bock, professor of physics at Caltech, laboratory senior research scientist at the Jet Propulsion Laboratory (JPL) and project co-leader. “We are measuring a signal that comes from the dawn of time.”

Our universe burst into existence in an event known as the Big Bang 13.8 billion years ago. Fractions of a second later, space itself ripped apart, expanding exponentially in an episode known as inflation. Telltale signs of this early chapter in our universe’s history are imprinted in the skies in a relic glow called the cosmic microwave background. Tiny fluctuations in this afterglow provide clues to conditions in the early universe.

Small, quantum fluctuations were amplified to enormous sizes by the inflationary expansion of the universe. This process created density waves that make small differences in temperature across the sky where the universe was denser, eventually condensing into galaxies and clusters of galaxies. But as theorized, inflation should also produce gravitational waves, ripples in space-time propagating throughout the universe. Observations from the BICEP2 telescope at the South Pole now demonstrate that gravitational waves were created in abundance during the early inflation of the universe.

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New Method Proposed For Detecting Gravitational Waves From Ends Of Universe

A new window into the nature of the universe may be possible with a device proposed by scientists at the University of Nevada, Reno and Stanford University that would detect elusive gravity waves from the other end of the cosmos. Their paper describing the device and process was published in the prestigious physics journal Physical Review Letters.

“Gravitational waves represent one of the missing pieces of Einstein’s theory of general relativity,” Andrew Geraci, University of Nevada, Reno physics assistant professor, said. “While there is a global effort already out there to find gravitational waves, our proposed method is an alternate approach with greater sensitivity in a significantly smaller device.

“Our detector is complementary to existing gravitational wave detectors, in that it is more sensitive to sources in a higher frequency band, so we could see signals that other detectors might potentially miss.”

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