`We can now track the birth, evolution and death of stars'
In some ways, the detection of gravitational waves (GWs) confirms the way the universe operates. In particular, it confirms a long-standing prediction of general relativity, adding to the earlier experimental confirmations. We also expected GWs to be real based on the observations of astronomers who have tracked the changes in binary pulsar orbits. But it is wonderful to be able to detect the waves directly! The fact that we detected two heavy black holes merging as our first signal is interesting. Some people expected that to be a common source, while others did not, based on different astrophysical modeling. So this event is already telling us something about how stars form and evolve to produce heavy binary black hole systems.
It was very hard to detect the waves. We had indirect proof before, but this is the first direct proof of their existence. Since events like binary mergers are rare, we have to be able to search a large volume of the universe, and the ones we detect tend to be rather far away. The gravitational-wave strain is very tiny when it reaches Earth. That's why it took many years of research to arrive at detectors which are sensitive enough.
This discovery is one more confirmation of our understanding of mass and gravity through general relativity, but this measurement does not say anything about other interactions of matter.
In the future, we will be able to detect things that aren't seen in other ways. Mergers of binary black holes and binary neutron stars, for instance. We'll also learn about the population and properties of those things in our universe. That will give us more information to test models of birth, evolution and deaths of stars and their galactic environments. PETER S SHAWHAN Associate professor of physics, University of Maryland, USA. He is closely associated with the LIGO project
(As told to DownToEarth)