Hiranya Peiris, an astrophysicist of Sri Lankan origin, recently made her country proud upon receiving the Breakthrough Prize in Fundamental Physics 2018. She was one among 27 other scientists who received this prestigious award for the detailed maps of the early universe made by the NASA satellite known as Wilkinson Microwave Anisotropy Probe (WMAP). Peiris is a Professor of Astrophysics in the Astrophysics Group at the Department of Physics and Astronomy, University College London with research interests in theoretical cosmology, cosmic microwave background, galaxy evolution and stellar kinematics and statistical methods in astrophysics. 

Speaking to W@W, Prof.Peiris shared her experience as an astrophysicist, her thoughts about the award and the future discoveries in physics. 

Q: What inspired you to become an astrophysicist?
A: My parents nurtured my interest in science and astronomy from a very early age. I voraciously read science fiction and was a member of the Sri Lanka Young Astronomers Association (with Arthur C.Clarke as a patron) as a kid. I met many like-minded people there – some of whom have also gone on to become astronomers. I was also one of a generation of astronomers inspired by Carl Sagan’s TV show “Cosmos”. Even then my early interest in astronomy would probably have remained a hobby except for the positive influence of my excellent maths teacher at the school in England, who both nurtured my interest in research and encouraged me to apply to Cambridge.

Q: You are known for your work in cosmic microwave background radiation. Tell us more about this field. 
A: The Cosmic Microwave Background (CMB) is the most ancient light we can see; it shows us the universe as it was 13.8 billion years ago. The CMB is nearly uniform. The tiny variations in its temperature reflect initial irregularities in the distribution of matter and radiation that later developed into the complex universe we see around us. The early universe is a “laboratory” for very high energy physics, up to a trillion times greater than the energies reached by the Large Hadron Collider at CERN. The origin of the Universe is tied to this extreme physics and imprinted in the primordial ripples. By studying this light, we can work out the physics of the Big Bang, and figure out the contents of the Universe and how it is evolving.

Q: Recently you won the Breakthrough Prize in Fundamental Physics. Tell us more about the ‘detailed maps of the early universe’.
A: The prize was awarded for the maps of the early universe made by the NASA satellite known as Wilkinson Microwave Anisotropy Probe (WMAP), which helped shape our understanding of the origin, evolution and nature of the cosmos. The mission mapped the cosmic microwave background – the light left over from the Big Bang – to allow scientists to work out the age of the Universe, its rate of expansion and its basic composition. My work on the mission, carried out when I was a PhD student at Princeton, involved analysing the first round of data from the experiment for cosmological interpretation.

Q: There is a dearth of teachers, lecturers and professionals who are interested in physics especially in a country like Sri Lanka. For those who are interested, there are limited facilities and infrastructure available to study physics. What are your comments regarding this?
A: It is true that to carry out ground-breaking experimental research in physics requires expensive infrastructure and investment. However, to get started in physics just requires a textbook and access to someone knowledgeable.  

Q: How is the scope for physicists/ astrophysicists globally? 
A: Physicists are trained to think independently and out of the box, and they are adept at using incomplete data to reach useful and robust conclusions. They are often excellent computer programmers. They have great communication and time management skills. For these reasons, other than in academic research they are highly sought-after in industry, engineering and finance.

Q: A female to take up this role is quite new to developing countries. How did your Lankan roots help you to be where you are today?
A: The value placed on education and hard work in Sri Lankan society still stands me in good stead. I was inspired by my mother, one of the first female civil engineers in Sri Lanka. I was brought up to believe I could do anything I put my mind to.

Q: Any plans to visit Sri Lanka in the future? 
A: It would be wonderful to visit Sri Lanka soon. I have not managed to visit for a decade now, it’s way overdue!

Q: What is most satisfying about your career?
A: The thrill of understanding a complex phenomenon that you didn’t understand before – and maybe no human understood before – is indescribably wonderful. I also gain a huge amount of satisfaction from mentoring junior researchers and watching them go on to do great science. I am very proud in particular of all my PhD students and their achievements. 

Q: The most challenging?
A: Being a cosmologist requires courage. You are asking the biggest and most difficult questions – that humanity has been asking for thousands of years. There is audacity in thinking you can answer them. We look out into the universe and see how insignificant we are in all that space and emptiness – and how rare and precious our life-bearing Earth is, that we are busy destroying as a species. 

Q: A message to the youth (especially girls) in terms of looking at physics as an interesting subject.
A: Physics is a discipline that encompasses a huge array of skills and areas of interest. Working as a physicist is very different from studying it in a dry textbook so I would advise any young student thinking about a career in physics to undertake a research experience of some sort. Research in my field is a very collaborative and international enterprise. My work involves a lot of mathematics and high-performance computing, the development of advanced algorithms and highly specialized databases to store and sift through the massive amounts data returned by cosmological sky surveys. Some of this work requires me to work in small groups with two or three other researchers, but I also contribute to large global projects with several hundred people in many countries. Since cosmology is very international, I travel extensively, discussing research findings, giving talks, and running workshops and seminars. I also enjoy sharing my knowledge and enthusiasm with my undergraduate and postgraduate students at the university. I feel like I have the best job in the world!

Q: Future plans and new discoveries to look forward to
A: We now know that not only is our universe expanding, but that it is expanding at an ever-increasing rate. Fuelled by a mysterious driver called dark energy, galaxies such as our Milky Way are rushing away from each other at such enormous acceleration that not even the powerful force of gravity can hold the universe together. In the coming years, I want to understand the makeup and evolution of our Universe by looking at comprehensive maps of the sky produced by the Large Synoptic Survey Telescope (LSST). LSST is a billion-dollar dedicated survey telescope living up to the Greek meaning of the word “synopsis” – looking at all aspects of something. The LSST is a synoptic survey in several ways: billions of objects will be imaged in six colours in an unprecedented large volume of our universe. This survey over half the sky also records the time evolution of these sources: the first motion picture of our universe. The survey will provide a very large, very rich astronomical dataset yielding catalogues containing billions of galaxies. I want to use this data to gain insights into the physics underpinning our cosmos.

Pic courtesy Max Alexander