Dr Priyamvada Natarajan is a professor of astronomy and physics at Yale University. She is a theoretical astrophysicist interested in cosmology, gravitational lensing and black hole physics. In particular, she has focused on making dark matter maps of cluster of galaxies, the largest known repositories of dark matter. She is also deeply interested in the history of science and is an active advocate of communicating science to public at large. Her book Mapping the Heavens has recently been published, and Priyamvada talks to Firstpost about her starry beginning, history of cosmology and if Planet Earth's the only one with intelligent life in the Universe.
What were your growing-up years like?
I was born in Coimbatore, Tamil Nadu, and grew up in Delhi. I have the privilege of being born into a highly intellectual family — my dad is an eminent educationist, and my mother is a geographer and sociologist. I grew up in a home full of books. Given my parents' social circle, I grew up meeting many writers, artists, musicians, scientists and academics. I loved maps and was deeply interested both in terrestrial and celestial maps and atlases from a very young age. We had a computer at home really early and I learned to program the Sinclair ZX spectrum and the Commodore 64. All of this of course dates me!
How did you get started on your starry journey?
As I mention in my book, I got my first taste of research while in high school working with Dr Nirupama Raghavan at Nehru Planetarium where I was active as an amateur astronomer. We tracked Halley’s comet avidly and I was busy making star-maps for the night sky over Delhi.
What is it about science, and more specifically about astrophysics, that gets you excited?
What excites me about science is the process of figuring things out. I t is so thrilling to understand a phenomenon, something that is observed in nature and have an explanation that de-mystifies it and allows us to comprehend it. As scientists we need to be really nimble and open — open to changing how we think. This very active way of engaging with the natural world that science offers is irresistible to me.
What is the basic premise of your research?
I have always been attracted to the invisible and the elusive, so naturally gravitated toward working in cosmology where the big open questions center around the nature of dark matter, dark energy and black holes. Dark matter constitutes the majority of the matter in the universe; however, it is not made of the ordinary atoms in the periodic table that we are made of.
Dark matter, as we infer it, is rather lazy; its presence is felt only via the gravitational grip that it exerts on stars and galaxies. It does not emit, absorb or reflect light in any wavelength; it merely deflects and is therefore unseen. My research involves mapping the detailed distribution of dark matter in the universe exploiting the bending of light en-route to us from distant galaxies. In particular, I have focused on making dark matter maps of clusters of galaxies, the largest known repositories of dark matter.
Could you explain how you got the idea of chronicling the history of cosmology?
As I mentioned earlier, I am interested in how science works — the process of discovery as well as the human side of science. The psychological motivations of the scientists are not discussed as they are meant to be objective pursuers of the truth. However, we are human and are driven by passions and personal motivations that inform how we think. I was particularly interested in how and why scientists themselves often resist radical new ideas, even when they are trained to be open and flexible. Even Einstein believed in the idea of a static and steady universe, and refused to accept the astronomer Edwin Hubble’s finding of the expansion of the universe, in consonance with Einstein’s own theoretical predictions. It was only when the data was overwhelming did Einstein finally accept that the universe was expanding. I also wanted to show how this is a special moment in cosmology, when there is a grand convergence of ideas, instruments and computation leading to a very rapid pace of progress.
My book provides a glimpse of some of the greatest cosmological discoveries — radical ideas that have reshaped our comprehension of the universe over the past century.
Do you think our planet is an aberration? What makes us small yet significant?
Well, it appears now, with the discovery of planets around other nearby stars both using ground-based telescopes as well as the Kepler space telescope that there are likely more planets than stars in the universe! This is so, as in several instances multiple planetary systems are detected around the parent star. Since this is the case, I believe that it is quite likely that there exists life in some shape or form, likely unrecognisable to us perhaps on other planets. We are unlikely to be the only life-forms around, although it does appear that intelligent life might be rare since no one has yet tried to get in touch with us. I think the discovery of these numerous exoplanets is humbling, we are but one pale blue dot — as Carl Sagan put it beautifully.
How have Indian astrophysicists contributed to the field; you mention Subrahmanyan Chandrasekhar... how can they continue to compete globally?
India, has a long and illustrious tradition in astronomy and mathematics. So we are not lacking in role models! As for what India needs to do to compete globally more generally in science is to re-integrate research and teaching at the undergraduate level. The Indian Institutes for Science Education and Research (IISERs) are an excellent initiative to do so and steps in the right direction. We also need to value the work that scientists do, we are getting a little too caught up in a very narrow definition of what it means to innovate. So I believe that scientific research should be supported and India should invest in what are referred to as blue-sky ideas. In 1543, when Copernicus shifted the pivot from the Earth to the sun, he could hardly have imagined that by 2015, we humans would create a spacecraft — the Voyager — that would actually leave the confines of our solar system.
What would your advice be to young scientists?
Just stay curious, learn as much as you can, and build a strong foundation in the basic sciences, mathematics and computers. Learn coding as early as you can. Computation is a powerful tool, one that is critical to all new discoveries in every field. And especially to the younger generation: read and learn by doing.
Lastly, you are a proponent for scientists to be good communicators. Why is that important?
I think science is amazing and we are learning so much about the natural world, the cosmos, our bodies, the brain — we are making such tremendous progress that it is imperative for scientists to share the excitement with the public. At some level, we as scientists, everywhere in the world are supported by governments and funded by the public so it’s incumbent upon us to show we are putting these resources invested in us to good use. I think as my one of poet friends, the late Becky Elson put it eloquently, we as scientists have “the responsibility to awe”.
Mapping the Heavens is published by Yale University Press