Dr Ramesh Prasad Sinha (1943–2021)

 

                                                                    Photo courtesy PC Hariharan

A great reason to go to work in a place like Tata Institute of Fundamental Research is that you get to meet and work with friends like Ramesh. We entered TIFR at about the same time in 1964, I as an IIT Bombay graduate and he as a graduate of what is now the BARC Training School. We were both interested in science in general and had formal training in multiple disciplines.

It is not uncommon for scientists to be very focused on their discipline. This was not our cup of tea! Ramesh and I had broad interests in science, and we had friends in many disciplines. Knowing Ramesh was to me like having a pass to audit courses in physics and astronomy. Another benefit I got from being a friend of Ramesh was getting to know several of his training school colleagues. One of them, Dr PC Hariharan, continues to be a friend to this day.

Ramesh and I got to meet soon after joining TIFR, more or less on the same day in 1964. Ramesh had earned an MSc in maths at Allahabad University and a master’s in statistics at ISI, Calcutta. Subsequently, he did the one-year post-graduate course at the Atomic Energy Training School, focusing on physics. He came to TIFR to do physics and had a keen interest in astronomy.

Our Work on Computers for Handling Telescope Data

This was the time a new breed of small computers, designed for handling scientific data and for online control of instruments, was hitting the market. Prof Govind Swarup, who headed Radio Astronomy at TIFR, was keen to utilize this type of computer to enhance data handling at the Ooty Radio Telescope. Ramesh and I teamed up together to make plans. There was a Varian Computer which met our expectations that was affordable. If I remember right, it was the Varian 620/i priced closer to 10,000$ than to 20,000$, and the US$ was worth only 25 Rupees. But getting dollars to import scientific computers was not that easy. If there had been a local agent, his commission could have been paid in rupees and we would need to ask for fewer dollars, but there was no local agent. There was no choice but for us to call up businessmen to ask if they would become the local agent of Varian! At the request of the purchase section, Prof MGK Menon, the Director, TIFR, made this call!

Blue Star agreed and our job of importing the computer became easier. Labs outgrow their computers like children outgrow their jeans. Ramesh and I teamed up again, to do the preparatory work to select a computer, and seek Government permission to import it.  A new phenomenon had to be faced now. Computer users, including major astronomy groups in the world, were making their software available free to each other. It did not matter if a computer was costly or cheap; it did not matter if it was relatively fast or slow! What was needed was the one which had the largest collection of usable astronomy software, ideally ready to plug and play. Ramesh and I went to Delhi and tried to convince the officials of our case for a Vax 780 computer. But they seemed to be under strict orders to minimize spending scarce foreign exchange on importing such things as computers! Finally, the Radio Astronomy Group did succeed in getting its VAX 780.

When Ramesh Received Homi Bhabha as a Visitor

The Ooty Radio Telescope site was inspected by Homi Bhabha before being finalized. Ramesh was the guide when Dr Bhabha went to inspect the site. (Prof Govind Swarup was being treated for a medical problem at the Breach Candy Hospital in Bombay at that time).  Swarup and Ramesh had done a lot of the searching of possible sites. The north-south slope of the ground had to be such that the telescope site could support a cylindrical radio telescope parallel to the ground and to the earth’s axis. It had to be large enough to house a telescope that was over 500 meters long 30 meters wide. It did not matter if leopards came for occasional visits!

A couple of years after work had begun on the telescope, Usha and I had been in Ooty for our honeymoon. Ramesh and Sudha gave us lunch at their place. We risked a leopard encounter in the interest of astronomy and visited the telescope site! Even now, you can ask Usha the latitude of Ooty. She will give you an answer accurate to 3 significant places!

Ramesh took keen interest in science, attended all important talks and read a lot. He also spoke his mind. However, he developed the feeling that the approach of using lunar occultation to get accurate measurements of radio sources was being given too much importance in the Group. He kept arguing for using Interplanetary scintillation as an alternative tool to enhance the accuracy of telescope observations. He encouraged many younger members of the team to look into this possibility. However, he did not choose to do some of this work himself and write a thesis. The Group was deep into a survey of the sky using the Lunar Occultation technique. One could not persuade them to take their focus away from this.  

Much later, in 2011, Ramesh looked back at his Bombay and Ooty years.  

In response to a question[1] about his papers, this is what Ramesh said, (covering only his work in India).

“I’ve been very poor at publishing papers. I ’ve been an idea man who’d work in a team, get things done, would not put my name up. So, (he lists papers that he wrote) two papers from Kalyan telescope. The paper announcing the construction and the completion of the Ooty telescope. Paper on pulsars, and no paper on Inter Planetary Scintillation”. He was in science because it was exciting. He was not in any hurry to earn a PhD. He preferred to go to the USA and do a PhD from scratch, taking courses and all.

Ramesh at the University of Maryland    

I met him a few times in the USA, when I was at the Carnegie-Mellon University, Pittsburgh, for a couple of years. Pittsburgh was not far from College Park, MD, where he and Sudha lived. I have been in touch with him later, meeting him several times during his Indian visits. However, the frequency of meetings could not be compared to what it used to be at TIFR. This was a great loss to me as the developments in astrophysics and cosmology in the decades since 1971 have been phenomenal. If I had been in touch with Ramesh, I would have understood more of it than I now do.

Ramesh, on the other hand, got into the thick of all that. Some of his work continued to involve big telescopes. After earning his PhD, he worked with the big telescopes at Green Bank, and wrote the calibration scheme of the Very Large Array in New Mexico.

Ramesh and a great experiment in astronomy, COBE 

There has been a great tradition in Physics of flying sophisticated experiments above the bulk of the atmosphere using high altitude balloons. Microwave radiation streaming in from all directions of the cosmos has also been studied this way. The radiation had seemed to be quite uniform, which could not be explained. The universe must have had seeds of the huge structures we see now, and the seeds must be seen in the radiation. Huge galaxies occur in big clusters and there are huge voids where there is nothing. Some astronomers found that the huge clusters of galaxies were attracting other galaxies gravitationally, making them move very fast. The time had come to put sophisticated experiments on satellites, to study all this better. In mid-Seventies, Nasa invited proposals for satellite-borne experiments. It took years for a project proposed at that time, named the Cosmic Background Explorer (COBE), to be launched. Ramesh contributed significantly to the design and implementation of the systems to collect and analyze data from this satellite.  

COBE achieved a lot. It confirmed that the cosmic background radiation was black body radiation at 2.725 deg K plus/minus 0.002 deg K. This was a necessary finding to confirm the theory that the universe arose in one big bang. The finding indicated that nearly all radiant energy of the universe was released in the first year after the bang. COBE also showed that the background radiation was not really uniform. It showed non-uniformities at the level of 1 in 100,000 in conformity with expectations from the great structures we observe of galactic clusters and voids. COBE also carried out surveys of Cosmic Infrared Background, and detected several galaxies which had formed very early in the evolution of the universe.

Image Credit: NASA
https://lambda.gsfc.nasa.gov/product/cobe/

COBE’s results have stood the scrutiny of comparison with results from two later satellite missions asking similar questions and using more sophisticated instrumentation. Not surprisingly, two Principal Investigators of the project John C Mather and George Smoot earned Nobel Prizes, in the year 2006. COBE had involved more than 1,000 researchers, engineers and other participants. John Mather had coordinated the entire process and also had primary responsibility for the experiment that revealed the blackbody form of the microwave background radiation. George Smoot had main responsibility for measuring the small variations in the temperature of the radiation. These were the evidence of the seeds for the huge clusters and voids that were to come. George Smoot calls them wrinkles in time. The clusters and voids that came out of these seeds were big enough to shape the fabric of space time around them, according to the theory of relativity.

Ramesh had worked in Mather’s team. It was a fitting finale to his lifelong work in astronomy, astrophysics and cosmology.

After the COBE project’s conclusion, Ramesh worked for some more time with NASA. During this time, he led the support for various NOAA/NASDA sea surface measurement efforts.         

Acknowledgement: I thank Velu Sinha, Ramesh's son and PC Hariharan, Ramesh's friend, for having read through my draft and giving me their comments.   

References:

1)  https://lambda.gsfc.nasa.gov/product/cobe/ for the image

2)  https://www.nobelprize.org/prizes/physics/2006/summary/

   

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[1] From an interview by Ms. Indira Choudhury with Ramesh in 2011. Indira is now at the Srishti Institute for Design in Bangalore. She had worked at TIFR. You may find the transcript of the interview in the TIFR Archives. Incidentally, the interview was held at my home in Bangalore.