The paper describes a new discovery, but there is no doubt that the paper has also drawn the attention of people working in the field to the capability of multibeam receivers, like that used at Parkes in the present experiment. The Parkes Multibeam Receiver was one of the key features that made our experiments successful.

One of the challenges of modern physics is the direct detection of gravitational waves. These are wavy ripples of the space-time continuum which, according to Einstein's Theory of General Relativity, must be generated by accelerated masses—such as two stars orbiting each other. We do have indirect evidence of the existence of gravitational waves, for instance the orbital decay observed in the original binary pulsar, PSR B1913+16, discovered by Russell A. Hulse and Joseph H. Taylor Jr., who were jointly honored in 1993 with the Nobel Prize in Physics. However, the strength of the gravitational radiation emitted by binary systems like the original binary pulsar is below the detection limit of present generation gravitational wave detectors available on earth, such as VIRGO in Italy, LIGO in the US, GEO600 in Germany, and TAMA in Japan. On the other hand, because these binary systems are losing energy in the form of gravitational radiation; their orbit is gradually shrinking, and the two stars will eventually merge, producing a burst of gravitational radiation.

The amount of gravitational energy released in such event in the form of gravitational waves is very large, and should be detectable by present generation gravitational wave detectors up to some distances in the universe. So, the estimate of the population of such systems in the galaxy (and by implication in the rest of the Universe) and the expected merger rate is crucial in order to understand whether the available detectors will be successful.

We have discovered a coalescing binary system containing two neutron stars and having a merging time much shorter than any other known similar systems, implying nearly an order of magnitude increase in the merger rate for double-neutron star systems. This system is the most "relativistic" observed so far, and besides the implications for the merger rate, it looks to be an excellent laboratory for General Relativity tests.

I started my collaborations with the Australians, in particular with Dick Manchester of the Australia Telescope National Facility, about 25 years ago. At that epoch I was a student working mainly in high energy gamma-ray astronomy, in the context of the COS-B European satellite mission, and I was interested in obtaining precise timing data on radio pulsars, in order to compare their properties with that observed at gamma-ray energies. I have found the observations of pulsars at radio wavelengths to be very exciting and I gradually got involved in a number of pulsar search experiments using the Parkes and Molognlo radio telescopes in Australia, but have also carried out pulsar experiments using the Italian Northern Cross radiotelescope, near Bologna in Italy. This was also a good opportunity to appoint students and post-docs, and gradually form a group of like-minded researchers. I thus spent several years in Australia, and usually travel to Parkes once or twice a year. My interests for pulsars are mainly triggered by the various applications that they offer in a variety of fields of fundamental physics. A few years ago, a large collaboration which included the Jodrell Bank group in the UK, the ATNF group in Australia and our group in Italy (formerly in Bologna and now in Cagliari), proposed the use of the Parkes Multibeam Receiver for a major pulsar search experiment, which ultimately led to the discovery described in the Nature paper. Now in Italy we are looking forward to the construction in Sardinia of a large radiotelescope, the Sardinia Radio Telescope (SRT), a major facility of the National Institute for Astrophysics (INAF), which should be 
commissioned in 2007.