The Classical Astronomer

Alumni Nov 3, 2018

NIVEDITA MAHESH (B.E Instrumentation and Control Engineering, 2008-2012) recently made it into the spotlight of the scientific community. The reason? For discovering the Cosmic Dawn, the light from the very first stars formed in the ancient universe. Nivedita is a member of the five-scientist group from Arizona State University, where she is currently doing her PhD.

Interview by Akiilessh S (B.E Mechanical Engineering, 2016-2020)

Akiilessh (A): Let’s talk about the Cosmic Dawn. Can you explain about your discovery in layman’s terms?

Nivedita (N): In a nutshell, our experiment gives us an indirect evidence that the Big Bang occurred. I can explain with a short story, if that can be considered as layman’s terms. So a fraction of a second after the Big Bang, there was this Hot Soup Bowl with just electrons, protons and photons. As we all know, electrons and protons constitute matter and photons constitute light. The Big Bang created matter and light but in a very dense state. That is, if you imagine a sphere where photons are trying to escape, they can’t because the electrons and protons keep forcing them to bounce back inside the sphere. Even if you want to look at Big Bang, you can’t; because the photons never came out of that era.

Now, slowly, with the expansion of universe (a result of Big Bang) and with time, cooling happened. The electrons eventually lost their energy and the photons finally escaped.

But this happened 400 thousand years after Big Bang. This is the first light, which is technically called the Cosmic Microwave Background Radiation. However, that’s not what we saw from our experiment.  What we saw was the First Light of the first stars.

So coming back to our story, now that the photons have escaped, the electrons and protons were not busy bouncing off photons. They combined to form the first element in our Universe – Hydrogen. This period in the history of the Universe (400,000 years after the Big Bang) is called the Epoch of Recombination. After this, the Universe became really boring for another hundred million years. Nothing happened except for Hydrogen lying around; this period is called The Dark Age.

Theoretically (and we believe it’s true), after some time, pockets of density were created due to Dark Matter. The Hydrogen clouds started collapsing due to their own weight to form Stars. These first stars radiated light. This first light interacted with the neutral Hydrogen still lying around, split it back into proton and electron. This period is called the Epoch of Reionization. So, from our experiment, what we claim is that the light from the First Stars interacted with the Hydrogen, split it and we’ve seen that signal. The effect of light from First Star.

A: So, we’re seeing the split up proton and electron.


A: Does that count as light?

Well, that counts as light because it’s the light from the stars that caused this. To put it in a better way, we saw the signal and not the actual light. It’s difficult to see the first light since we’re talking about very first stars and they are very old.  

A: So, we are finding the evidence that light from the First Stars has caused this.

You actually titled my paper(laughs). That’s true. Evidence of the First Stars. Our big discovery, that’s what it is.

A: Got it. So, you’ve been working with different researchers. Can you tell about your experience of working with people from other countries?

N: When I was in PSG Tech, I did a project in the 7th semester with Selvakumar Sir from I&CE department. He used to tell me, “Don’t do research just to submit a project thesis”. He gave me a glimpse of how research is done. After that, as a final year (semester) project, I got an opportunity of working at Raman Research Institute. It was a life changing experience for me.  The work there was related to astronomy and I felt lost coming from an Instrumentation background. But a professor told me, “I don’t care who you are, what your grades are or what your background is. If I give you a book and a few days’ time, you can learn all that is needed. Education is not about learning; it’s about teaching how to learn”.  

There was absolute freedom of interaction at Raman Research Institute. I never called anybody ‘Sir’. People working there were well experienced folks with several journals in reputed publications. And I could still call them by their first names. I worked with Dr Avinash Deshpande then and he insisted that I called him ‘Desh’. My desk was right next to his and if I wanted to show him anything, he would literally peep over and look at it. Even now, whenever I meet him, he introduces me to his friends saying, “I worked with Nivedita”(laughs). So you see, for a fresher out of college like me, the whole experience was encouraging and fascinating.

During my final year, I attended campus interviews and got placed. I worked at ABB for eight months and quit my job after realizing that a corporate job isn’t my cup of tea. I wasn’t quite fond of the work culture, the repetitive nature of jobs or the ladder of hierarchy there. So, I came back to Raman Research Institute. This time, I worked with Dr Ravi Subramaniam. He is the Director of Raman Research Institute but I still address him as “Dear Ravi” in all my mails. We shared an office and my first authored paper was with Ravi. We had developed a tech called ‘Beam Splitter’. It was huge and had to be tested outside Bangalore where there is no interference. So, we took a car to get there, sat on field, operated and noted down the results. And we did it all together.

The ‘Beam Splitter’ designed and constructed by Nivedita and her team

People often say that you have to go abroad to know what actual research is. I disagree. The work culture in research is direct. And it is the same wherever you go.

A: Is there any difference between our country’s research facilities and the ones there?

Not really. At least in the research centers I’ve been to, no.

A: So, more about your interaction with fellow researchers abroad?

N: After my stint at Raman Research Institute, I went to UCLA for my masters. Over there, I worked in Antenna Research lab with professor Yahya Rahmat-Samii and I had a similar experience. He had a separate office but he used to walk in with us everytime we were at work. Now in ASU, I work with Judd Bowman. My office is opposite to his and everytime I have clarifications, I barge into his cabin and he’d be like ‘Nivedita’ (and laughs).

You see, researchers believe that we are all the same. And that’s really important. Because, only when there isn’t any hierarchy, we can be open to new ideas. In India, this kind of ecosystem exists only in research institutions and not in colleges. I think that needs to be changed, at least when you are working in projects. You shouldn’t feel like your colleague is a professor. And I had this experience with Selvakumar Sir.

A: You joined engineering. How did you develop interest in astrophysics? Was it from childhood or…?

N: I didn’t have big aspirations as a child. My inspiration was my Dad who is an Electronics Engineer. So back then, he would make me do small projects at home like dismantling radios, and making power circuits. We had breadboards at home and I used to work with them from 6th or 7th grade. So, I thought engineering was the way to go because that’s what my Dad did. The good part about joining Instrumentation and Control Engineering is that it gave me a glimpse of things like control systems and sensors that could be the bases of anything. From there, I could easily go to Electrical Engineering (Masters) where I worked with antennas. My final year project at Raman Research Institute was to design an antenna for Solar Physics. I was able to do it without any deep understanding of Solar Physics only because of my branch.

At Raman Research Institute, there is a coffee talk every wednesday where PhD students talk about their research. They were interesting and I became interested in Astrophysics after knowing that there is scope to work on it. During my work, I realised that my Electrical fundamentals regarding antennae weren’t strong. So I joined Electrical Engineering in UCLA. Everytime, I made choices keeping in mind that I am going to work in Astrophysics for which specialising in Antennas and Electromagnetism is important. So yeah, my story is not something like “Once, I looked at a star and I wanted to be there”.

A: Can you tell us about your Graduate Experience?

N: My purpose of applying to UCLA was to work with Yahya Rahmat-Samii. He is one of the world’s best people in the field of antennas. He has even worked with Mike Jura (Late Micheal Jura, a distinguished astrophysicist) on a project in astronomy. I took a lot of courses related to astronomy and worked on many projects.  So, in summer, I had an internship offer from CST, an antenna modelling company and another offer from JPL(Jet Propulsion Laboratory, NASA).

A: What? JPL?!

N: The story does not have a good ending (laughs). I turned down the offer from CST and meanwhile JPL started the security process for my joining there. And they turned me down since I’m not a US national. So, at that point I couldn’t work in UCLA [‘twas summer and nobody works in labs at that time]. When I was in Raman Research Institute, my professor introduced me to Dr. Shrinivas Kulkarni (Author Sudha Murthy’s brother), an astronomer and professor at Caltech (California Institute of Technology). So, I mailed him, requesting for projects to work on over the summer and the very evening he called me. I had a telephonic interview and the next day I started to work in Caltech.

Caltech is a place with amusing details. For instance, the elevator has Maxwell’s equations on its walls and the shape of the building was based on a specific geometry. I had a great experience at Caltech and met amazing people there.  Since my internship was arranged at the last minute, I couldn’t find a place to stay. Commuting wasn’t a feasible option since UCLA and Caltech are 30 miles apart. Shrinivas Kulkarni (the then Chairman of the Astro Department) offered that I stayed at his place. So for three months, I had a little ‘Gurukul’ experience. We would work on the project in the mornings and discuss astronomy in the evening. And on Sundays, we used to watch old English films. He’d serve me a drink and give a puzzle to solve at his poolside. I had a great experience working with him.

This is what I mean when I talk about hierarchy. The barrier between a student and professor broke down when I got into this field. Learning became comfortable. Like you can have coffee or wine and learn over that.

A: Wow, that’s quite an experience you’ve had. So, what do you miss about Coimbatore? How was your life in PSG Tech?

N: Oh, I miss ‘kaalan kadai’! I don’t know if you’re going to put that down (laughs), but that’s what I genuinely miss. Whenever I come to Coimbatore, I’ll be like ‘Let’s go get some Kaalan’.

About college, I would say I was one of the notorious kids in college. I sat in the last row, walked in late and bunked classes. I scored good grades so my professors used to say  “Nivedita, you may score marks, but you need to be more disciplined in life.”

I had a good time but I wish I had been more disciplined. Because when I moved out of college, the undisciplined nature of mine carried over. I was going late to research labs and I was not making much progress. Then I realized that I have to be careful if this is what I wanted to do in my life. So yeah, I did have fun in college. It is okay to make memories. Go out and have fun, but you have to study. And I was not someone who would get distracted in class.

I was also involved in a lot of activities here like E-Club and YLGC. I was also part of the dance team (RoughAddictz). We participated in Saarang in the 1st year itself.

A: How do you kill time when you are not pondering over the universe?

N: I’m a trained classical dancer. I continue to practice wherever I am – be it in Bangalore, UCLA or ASU. In fact when i joined ASU, there was no Indian classical team there. It was quite surprising as there are many Indians there and every prominent college in the US definitely has an Indian classical team. So last year, my friend and I started an Indian classical dance team in ASU. Now, we have like 7 members. We’ve successfully conducted 3 workshops and performed at major events in Arizona.

A: No books or TV Series?

Ohh, I love TV Series. I used to read books when I was doing my Undergrad and Masters but after that I stopped. I couldn’t read books right after reading research papers. Of late, I’ve been watching Brooklyn Ninety-Nine. I’ve watched Sacred Games and Game of Thrones. GoT is my favorite and Stranger Things is my second favorite. So, yeah I watch a lot of TV Series.

A: A couple of rapid fire questions, just to spice it up. MARVEL or DC?

N: (laughs) Can I be one of those people who like both?

A: Star Wars or Star Trek?

N: Star Wars.

A: Words of wisdom for students aspiring to do research, especially from engineering background?

N: I would say, try to get deep into the things you like. Enjoy learning. I still remember my friends making fun of me for this. So, I used to like Sensors classes a lot. I was very interested in learning the topics in it and I would read and explain them to my friends with analogies. For instance, we were learning about antennas – transmitting and receiving antennas. I don’t know if you can quote this but my analogy was “If you are admiring or interested in someone, it means you are sending out signals (transmission). But he is not aligned or polarized with you and that’s why he is not receiving your signals” (giggles). What I am trying to say is, read a lot; learn with examples that are interesting and can make the common man understand. I used to tell my mom about the Big Bang with the Hot Soup Analogy. Once you give analogies, people will love the subject. You may like engineering, science or art. No matter what it is, just go and do something in it. Don’t just keep ‘liking.’

We at THE BRIDGE would like to thank Nivedita for her enthusiasm towards the interview and wish the astronomer the best in all her endeavours. We’d also like to thank Mr JAI HARI (I&CE 2008-2012) who had helped us connect with Nivedita.

About the Author:

Akiilessh S

I am a science and tech lover; a bibliophile and a music lover. I also like playing Kerbal Space Program.

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