Originally posted on sciy.org by Ron Anastasia on Thu 17 Sep 2009 03:57 PM PDT
Monday, September 14, 2009
Astronomers Plan Galaxy-Sized Observatory For Gravitational Waves
(Excerpted from an article on the MIT Technology Review website)
Gravitational waves squash and stretch space as they travel through the universe. Current attempts to spot them involve monitoring a region of space several kilometres across on Earth for the tell tale signs of this squeezing. Although great things are expcted, these experiments have so far thrown up precisely nothing.
But there's another way. Gravitational waves should also stretch
and squeeze pulsars as they pass by, subtly changing the radio pulses
they produce. So by monitoring an array of pulsars throughout the
galaxy, astronomers should be able to see the effects of nanohertz to
microhertz gravitational waves passing by. The array of pulsars should
effectively shimmer as the waves wash over it, like a grid of
buoys bobbing on the ocean.
So the plan is to keep a beedy eye on an array of carefully chosen pulsars. It's called the North American Nanohertz
Observatory for Gravitational Waves or NANOGrav and it's part of an
international effort to spot gravitational waves in this way.
Of course, these kinds of observations are hard to make. First, astronomers need well-characterised millisecond pulsars to observe. They're not easy to find and there appears to be a particular dearth of them in the northern hemisphere. And measuring them with the required accuracy isn't easy either, say Fredrick Jenet at the University of Texas, Brownsville, and a few buddies.
But there's hope on the horizon. These guys say the next generation of radio telescope arrays such as the Allen Telescope Array in California and the Square Kilometer Array in Australia or South Africa, should be capable of making the required measurements. And the scientific potential of the data is huge. ... (Article continues at link below.)
This article is abstracted from the MIT Technology Review website: https://www.technologyreview.com/
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