pulsar timing arrays

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Ripples In Spacetime: From Einstein To LIGO And Beyond

“As you take a journey through the discoveries that have confirmed the existence and properties of gravitational waves, you wind up at the present day, where the future possibilities are clearly laid out at your feet. Pulsar timing arrays are opening up the ability to explore the long-wavelength gravitational waves that no interferometer can measure, and may in fact see the types of waves BICEP2 was seeking. Future observatories on the ground will complement the LIGO array, and are already under construction and coming online. LISA is on its way and will open up gravitational waves in space, and the ripples from supermassive black holes. And in the future, the holy grail of correlating optical and other light-based astronomy with gravitational wave astronomy will be achieved with our planned technology.”

In 2015, for the very first time, gravitational waves were directly detected from the merger of two massive black holes. These ripples in space traveled over a billion light years before they were finally detected. When they were, it validated Einstein’s theory of General Relativity in an entirely new fashion, and proved the physical existence of a phenomenon that was doubted even by Einstein himself. In a stunningly well-researched and well-written book, Ripples In Spacetime, award-winning science writer Govert Schilling takes us on a journey that not only details how these waves came to be detected, but it puts the entire story in historical and scientific context. The past, present, and future of gravitational wave astronomy, plus what it means for humanity and the scientific endeavor, is brilliantly discussed.

Come take an in-depth dive into what wonders this book holds – particularly if you’re a LIGO skeptic – and if you like what you’re reading, pick yourself up a copy and get the full story!

4

Mysteriously Quiet Space Baffles Researchers

“The emission of gravitational waves in these systems is a consequence of Einstein’s theory of General Relativity. Combine the existing observations with the calculation for the emission, and you get an estimate for the background noise from gravitational waves. The pulsar timing measurements we make from pulsars within our own galaxy should be sensitive to this noise from the gravitational waves. But the new measurement — the null result — is inconsistent with all existing models for the gravitational wave background in this frequency range.”

We live in a Universe full of galaxies, supermassive black holes, and violence. The violence is particularly relevant here, because every so often, these galaxies merge, and if they each contain a supermassive black hole, the gravitational wave “ripples” that get sent through space will literally shake and affect everything that’s in them. If you had a perfect clock — something that kept time perfectly that you could watch “tick” — you’d expect to see the timing of these ticks be affected. Astrophysics gives us these clocks: millisecond pulsars, in great abundance. Yet the Parkes Pulsar Timing Array project has just completed an 11-year survey of thousands of them, and found no evidence of the gravitational waves they were expecting.