Evidence of ultra-low-frequency gravitational waves in space has been greeted with immense excitement in the world of science. This was not only due to that mind-bending finding in itself, but also the possibilities emerging from it. Everything around us is constantly being roiled by these waves, it suggests. Space-time “churns like a choppy sea” and is disturbed by violent events causing ripples in the distant universe that have occurred over the past 13-billion-plus years.
The word awesome is apposite in describing the endeavour; the collective efforts of hundreds of astrophysicists all over the world, including some from Trinity College Dublin and the University of Galway. It is a reward for persistence as it was the culmination of 25 years’ work, and underlines the merits of international co-operation on research despite geopolitical tensions on other fronts. The results came from observations from six of the world’s most sensitive radio telescopes.
Einstein’s first great leap was realising space and time were different dimensions of the same underlying thing – space-time. Such waves were first predicted by his General Theory of Relativity in 1915. They are believed to be produced by “supermassive black hole binaries”; pairs of black holes with masses billions of times that of the sun located in the centres of merging distant galaxies, and stirring up gravitational waves in space-time.
Pulsars are the collapsed remains following the explosions of massive stars. The fastest pulsars rotate at a speed of 700 turns per second and emit a beam of radiation from their magnetic poles. “They behave like cosmic lighthouses, and they make excellent natural clocks,” explained one of the researchers. They used the incredible regularity of their signals to search for minute changes in their ticking to detect the subtle stretching and squeezing of space-time by waves originating from the distant universe. These waves carry information about some of the best-kept secrets of the cosmos and provide clues about how galaxies formed and have evolved. A new astronomical era is set to dawn.
