Shining a light on black holes: Revolutionising our understanding of the universe from the dawn of time
For Professor Andreas Freise, the future is black. It is very black – but in a good way.
That’s because Andreas is dedicated to shedding light on the dark side of the universe – the likes of black holes and neutron stars, of which scientists still know very little but are poised to discover a lot more.
For the past few decades, physicists have been trying to listen in to the universe’s ‘gravity channel’, which has been broadcasting since the Big Bang through the extremely weak form of radiation known as gravitational waves – ripples in space-time caused by violent cosmic events such as the explosion of stars or the collision of two black holes.
Now, says Andreas, they are perhaps only two years away from success.
If it happens – and he is confident it will – Andreas and the Gravitational Wave Group at the University will have played a pivotal role in revolutionising our understanding of the universe from the dawn of time.
German-born Andreas, who is Professor of Experimental Physics in the School of Physics and Astronomy, has been at the forefront of the optical design of new gravitational wave detectors. Called interferometers, they are ground-based, km-long instruments that use mirrors to bounce laser light repeatedly along their two ‘arms’ to intercept any passing gravitational waves. Research performed by Andreas and his PhD students – using tabletop experiments and numerical models to explore and validate new ideas – has changed the design of several international detectors.
Albert Einstein’s theory of general relativity predicted gravitational waves a century ago, but their detection has so far eluded scientists, and finding them remains one of the great challenges in experimental physics.
In his recent Inaugural Lecture, entitled ‘Shining a light on black holes’, Andreas explained some of the difficulties scientists had to overcome to get to where they are now: on the brink of making new, out-of-this-world discoveries.
The problem is that the effect of these gravitational waves on us and on the earth is very tiny. Einstein predicted that we would never be able to measure them because they are so weak. What we have done over the last 40 years is to build better and better instruments that will allow us to detect gravitational waves soon. To do this, we have had to push the boundaries of technology: for example, we now have better optical materials, the most stable lasers and also completely new measurement techniques.
Andreas, who has been at Birmingham for a decade, has been working in this relatively new field of science for more than 15 years: He gained his PhD in 2003 from the University of Hannover for developing new optical simulations and for significant contributions to the experimental realisation of the German-British gravitational wave detector GEO 600. He then became a post-doctoral researcher at the newly established European Gravitational Observatory in Pisa to work on the Virgo detector, continuing his work to bring the first generation of gravitational wave detectors online.
He and his University colleagues are among about 900 scientists from across the world collaborating on a major project called LIGO (Laser Interferometer Gravitational-wave Observatory) located in Livingston, Louisiana and Hanford, Washington. The LIGO detectors have been recently upgraded and are now ten times more powerful than before – and could be listening to gravitational waves in two to four years’ time.
‘They are switched on, but not yet working at full sensitivity; but we will start the first data collection this year,’ says Andreas. ‘Over the next few years we will switch between improving the detectors and taking data. During that time we expect the first detection – probably the vibration from the last moments before two neutron stars collided. We believe that in a few years’ time we will have between a few and many tens of detections.’
Although not an astrophysicist, Andreas is particularly interested in the dark side of the universe – such as how many black holes there are, what mass they have and where stars go when they die.
‘We are already developing the next upgrade of the existing detectors to look further into the distance of space and to extract more information about the signals we observe,’ he says. ‘I believe that in the coming ten to 20 years our data will have a profound impact on astronomy and our understanding of the universe.
‘I feel very lucky to do what I do – and to have chosen exactly the right moment to come along for the ride. Not long ago we were pioneers; now our field is emerging into the mainstream. I very much enjoy my job – working with enthusiastic and inspiring colleagues and students is the most exciting aspect – and it is a real privilege to be able to do it.’
Professor Andreas Freise delivered his inaugural lecture on Wednesday 13 May 2015.
More information about the University of Birmingham Gravitational Wave Group is available online at www.sr.bham.ac.uk/gwgroup