Forget building gravitational wave detectors costing hundreds of millions of dollars (I’m looking at you, LIGO), make use of the most accurate cosmic timekeepers instead and save a bundle.
The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) is a proposal that involves closely monitoring the regular flashes of spinning neutron stars (or pulsars) to detect very slight “shimmers” in their signal. Although the physics is crazy-complex, by tracking these shimmers over a suitably distributed number of pulsars could reveal the passage of gravitational waves.
However, there’s a problem with this plan; pulsars are notoriously tricky stellar objects, as my colleague Jennifer Ouellette points out:
The problem is that you need to closely monitor rapidly-spinning millisecond pulsars, which are (a) tough to find (only 150 have been found over nearly three decades since pulsars were first discovered), and (b) not very plentiful in the part of the night sky of interest to scientists (northern hemisphere). They tend to clump together in globular star clusters, which makes them useless for detecting gravitational waves.
However, according to results announced by the National Radio Astronomy Observatory (NRAO) at this week’s American Astronomical Society (AAS) meeting in Washington D.C., they’ve discovered 17 new pulsars with the help of NASA’s Fermi Gamma-Ray Space Telescope.
In addition to recent Fermi telescope pulsar discoveries, it would appear that the number of potential targets for NANOGrav are increasing, making a stronger case for the 10 year, $65 million project…
You have to wonder whether building the Laser Interferometer Gravitational-Wave Observatory (LIGO) was worth it (but you can’t be too careful, some terrorist organizations might want to use gravitational waves for evil, so it would be good if we detected them first).
Source: Discovery News
astroengine.com 
While there's definitely a rivalry between these two approaches, I don't think I'd go so far as to say LIGO (or LISA) is a waste of money. The two techniques look at very different wavelengths, so they're complementary rather than mutually exclusive options. Few people would say that we shouldn't build radio telescopes because optical telescopes are cheaper, would they? 🙂
Very true. I've just always been dubious about LIGO for quite some time — I had this gut feeling that gravitational waves are more likely to be discovered through more elegant means, and NANOGrav is a rather lovely concept in that regard. I suppose that I'm personally disappointed with the null results coming out of LIGO — I remember all the excitement surrounding the project's completion and now LIGO scientists are sounding more than a little frustrated. I want to see the signature of a gravitational wave already! 😉
This post puts light upon one of the basic concept of science i.e Gravitation….Learning more about gravitational force has always being a very curious and fascinating thing to learn about for me.
Physicists do not understand gravity. There are two long-distance interactions i.e. gravity and electromagnetism. It suggests that there are two spacetimes/fields i.e. the Newtonian spacetime responsible for the gravity and the Einstein spacetime responsible for the electromagnetism. The Einstein spacetime is ONLY indirectly responsible for gravity because the gradients produced by masses in the Newtonian spacetime produce also gradients in the Einstein spacetime. The negative result of the Michelson-Morley experiment suggests that there is in existence the Newtonian spacetime composed of TACHYONS. It means that we will never detect gravitational waves moving with the speed of light in vacuum.