By IANS,
Washington : Scientists are still looking for gravitational waves — small ripples in the fabric of space-time which are considered to be the sounds of the universe.
Just as sound complements vision in our daily life, gravitational waves will complement our view of the universe taken by standard telescopes.
Albert Einstein predicted gravitational waves in 1918. Today, almost 100 years later, advanced gravitational wave detectors are being constructed in the US, Europe, Japan and Australia to search for them.
The prime candidate sources are mergers of two neutron stars: two bodies, each with a mass comparable to that of our sun, spiralling around each other and merging literally in a blinding flash, reports the journal Nature.
Such events are rare and take place once per hundreds of thousands of years per galaxy.
Hence, to detect a signal within our lifetime the detectors must be sensitive enough to detect signals out to distances of a billion light years away from the earth, according to a Hebrew University statement.
This poses an immense technological challenge. At such distances, the gravitational waves signal would sound like a faint knock on our door when a TV set is turned on and a phone rings at the same time.
Therefore, astronomers have been looking for years for a potential electromagnetic light signal that would accompany or follow the gravitational waves.
This signal would allow us to “look through the peephole” after hearing the faint knock on the door, and verify that indeed “someone” is there.
Tsvi Piran, professor at the Hebrew University of Jerusalem, and Ehud Nakar from Tel Aviv University describe having found just that.
They noticed that surrounding interstellar material would slow debris ejected at velocities close to the speed of light during the merger of two neutron stars. Heat generated during this process would be radiated away as radio waves.
The resulting strong radio flare would last a few months and would be detectable with current radio telescopes from a billion light years away.