Apollo astronauts left an array of seismometers to study moonquakes. Now astrophysicists are scouring the data for evidence of gravitational waves
One of the great unanswered questions in science is whether the universe is filled with gravitational waves and if so, whether we can spot them. This question comes directly from Einstein’s theory of general relativity which assumes that the fabric of the cosmos is able to warp, bend and vibrate like a rubber sheet.
The bending and warping effectively causes gravity, the effects of which we can measure in detail. The vibrating is gravitational waves but physicists have yet to see this directly. However, they are hugely confident that gravitational waves must permeate the universe and have spent hundreds of millions of dollars building machines to spot them, so far unsuccessfully.
in recent years, a number of scientists have begun to point out that there may be much cheaper ways of finding gravitational waves. One idea is to study pulsars since the precise signals they send out must “shimmer” when gravitational waves pass by.
Another idea is to look at the Earth itself. The thinking is that it must vibrate like a bell when gravitational waves pass by. So there could be signs of this vibration in the data collected by the global network of sensors set up to measure seismic vibrations around the planet…..
… Read more at medium.com and http://arxiv.org/abs/1409.4680