MAKING WAVES

An IUCAA scientist Sanjeev Dhurandhar was one of the 700 odd scientists who participated in this international collaboration of US based LIGO and Italy based VIRGO observatories.

Although this is a null result – as scientists were not able to detect the waves – this paper has ruled out several models of the big bang theory — including the String theory,deepening our knowledge of the universe.

Gravitational waves emit from any massive body; it was first predicted by Einstein and in the 1920s the theory of gravitational waves famously resolved the deviations of Mercury’s orbit,known as Mercury’s perihelion.

“This collaboration has breached (or lowered) the upper limit set on the gravitational wave background,” said Sanjeev Dhurandhar,a scientist from IUCAA.

Lowering the upper limit has narrowed the band at which Gravitational Waves could possibly be detected for future searches.

Experiments for the detection of GWs has been going on for over five decades. Scientists are eager to detect them as the GWs – unlike Electromagnetic waves — are pure carriers of information of their sources – which means they are little affected by other stars,galaxies or any background source.

Their detection will,thus,open a rich vein in the study of their sources,directly extending our understanding of the early universe. “Their detection would also provide a direct proof of the existence of black holes,” said Dhurandhar.

The data for this study was collected from November 2005 to September 2007; scientists were studying background signals from sources originating from anywhere in the universe.

Till now,scientists have only indirectly observed the gravitational waves by studying the minute differences noted by the GW detectors. These detectors can only be disturbed by gravitational waves.

The US based Laser Interferometer Gravitational Wave Observatory (LIGO),is the largest observatory for gravitational waves. The others are the Virgo detector in Italy,the GEO detector in Germany and several smaller detectors in Japan.

Dhurandhar has been involved in the study of gravitational waves since 1989.

He joined the collaboration in 2000 and has devised several data ananlusis techniques for the observation of gravitational waves. He has a PhD from TIFR and continues to hold a post at the Pune university.