Yesterday saw the announcement of the discovery of gravitational waves by LIGO, in what is being described as the most important breakthrough in physics for decades. Now scientists from Queen’s University Belfast are leading the hunt for the source of these ripples in space.
In a spectacular announcement yesterday, The Laser Interferometer Gravitational-Wave Observatory, (LIGO), a US based experiment, announced that they detected exactly the same pattern of space distortion in two different experiments separated by a continent and the time difference between the detections matches the speed of light across the USA.
The remarkable discovery has been years in the making, as the work on these two extraordinary detectors started in the early 1990s. In September 2015 they finally achieved the unprecedented new precision that produced this discovery.
The LIGO team have detected a signal from two massive black holes (each about 30 times the mass of the sun) spiralling around each other and finally crashing together. The ripples in space and time from such an event were predicted by Einstein is his theory of General Relativity over 100 years ago. Finally, the elusive signals appear to have been found.
These signals are expected to come from pairs of black holes and neutron stars merging together and they may be relatively common in the Universe. The next step is to try and actually see these violent events with telescopes working in the optical and with telescopes that detect x-rays and radio waves. Scientists at Queen’s University are playing a leading role in this search and today released their findings from their first attempt at pinpointing the source of these gravitational waves.
Queen’s have been partners in the Pan-STARRS project since 2008 and together with NASA, the University of Hawaii and Harvard University they are using this powerful telescope system to survey the sky to find what caused the gravitational wave. They were given confidential access to the information about the discovery back in September 2015 by LIGO and immediately pointed the Pan-STARRS telescope at the large sky area the source was thought to be in.
Professor Stephen Smartt, Director of the Astrophysics Research Centre at Queen’s, and who leads the project explained: “Finding gravitational waves and then looking for the source is like the difference between hearing and seeing. If you hear an explosion, you know roughly what direction it came, but you then immediately turn your eyes to see what caused it. This is exactly what we are doing with Pan-STARRS.
“The LIGO experiment “hears” the ripple and can only indicate roughly were on the sky the waves came from. That area is about the size of 2000 full moons. We point Pan-STARRS at that area and see if we can pinpoint any unusual looking explosion or outburst in optical light.”
In explaining the results of their first search, Professor Smartt explained: “We didn’t find anything in our data that was likely related to the gravitational wave source. That’s not totally unexpected. We found over 50 new sources that are normal supernovae – exploding stars that we find all the time. We didn’t see any hint of unusual behaviour. There are two likely reasons. One is that the predicted sky area was so big a large part of it was in the southern hemisphere and we couldn’t see it from Hawaii. The other is that the source may have been too faint for us to detect it. But we have shown that we can search these sky areas quickly and in the future we can take longer exposure times to look for fainter sources”
Dr Ken Chambers from University of Hawaii added “This is the first detection of gravitational waves and our collaborative project with, Queen’s, Harvard and NASA is one of the best in the world at trying to identify the sources. We are going to be looking very hard for these merging black holes and neutron stars over the next few years.”
Queen’s University will continue to work with NASA, Harvard University and the University of Hawaii over the next three years to find the source of the gravitational waves.
For a video of Professor Stephen Smartt speaking about his work visit: https://youtu.be/xmWXW-hEWvE