Dialogue with a Cosmologist: Part 1

This is part-1 of a series of blog articles, which will explore some of the biggest questions of cosmology and physics through a fun and short conversational format. In this series, I document conversations and Q&A sessions with Swagat Saurav Mishra, a senior research fellow at IUCAA, who works on early universe physics, inflationary cosmology and primordial black holes. I will also document some of my comments, questions and notes along the way to keep the narrative clear and easy to digest. We are, after all, trying to digest the nature of reality here!

It doesn't really take much effort to experience a sudden sense of awe for the universe you live in. Yes, you're a busy human who is submerged in this colourful world of chaos, complex societal structures and norms, and you have a plethora of things to do if you want to avoid boredom. Nevertheless, a few minutes of silence and real contemplation about where you are, who you are, and what reality is, is sufficient to awaken you and take you on a spinning ride through the insane, unbelievable truth of it all. As Sagan would say, "you live on a mote of dust, suspended in a sunbeam." You're riding a small piece of rock, that's revolving around a powerful, nuclear fusion machine while hurtling through cold, dark space.

Space! There is just so much of it, so much that you suddenly want to hold on to your couch a little bit tighter. This little island of trees, water and weird biological organisms that we call Earth is all you really have, and the rarity of anything existing at all becomes suddenly apparent to you.. forget life, even matter is so rare! There are, on an average, just about 6 hydrogen nuclei in every cubic meter of space..an incredibly empty universe! However, just as your imagination flies you through the cold, distant reaches of empty space, you quickly draw your attention back to the buzzing phone near you, or the funny cat meme you read this afternoon. Who in the right mind would want to spend any time thinking about the overwhelming vastness of the universe, and the possibility of everything you know and love being a mere accident or a timely incidence and statistical play of nature, when you could just as easily be spending your time doing other things that seem to... 'matter' more? (this is meme worthy).

I admit, there are not a lot of people in the world who would even remotely consider diving into the 'study of the universe' as a profession. Yet, there are a few, very dedicated people out there, who today stand at the very edge of science and our understanding of nature. They represent much of humankind's progress as a species over several centuries, from the fight for survival to the cognitive revolution, all the way to decoding signals from the big bang. We have come a long way, and it is every person's right and responsibility to at least be aware of some of our progress over the years.

So in all honesty, if you ever meet a cosmologist, know that what he or she does takes real courage and audacity. Not because the math is hard, but because it takes a certain fearlessness to tackle nature's biggest, toughest mysteries, and to commit one's life and time to solving the puzzles that this universe has presented before us. It takes thousands of "digesting reality" mind-trips to build a physicist, because he not only needs to be in love with the beauty of it all, but also needs to be a ruthless skeptic in questioning and judging his own work. It also takes a lot of patient studying, obsessive work ethic and furious note-taking to master such a subject.

Let's talk to a physicist now, shall we? Meet Swagat Saurav, a senior research fellow at IUCAA, Pune. In his own words, he explains his work and the basic idea behind his doctoral thesis:

Swagat: "I work on open problems in Cosmology - origin of the Universe, nature of dark matter and Dark energy. Over the past two years, my research work has mostly been related to the very early Universe when our Universe was less than 1 second old. I study the effects of quantum mechanics during Cosmic Inflation, a phase of rapid exponential expansion, very close to the beginning, responsible for all structure in the Universe from planets to galaxy clusters. Currently I am working on studying the beginning of our Universe using primordial gravitational waves"

Some of the topics he mentions above are thriving fields of current research, and these compelling, unresolved mysteries and questions about dark matter and inflation have been around for a couple of decades now. But isn't it really, really hard to know what's happening that early in the universe? We haven't even nailed down human history properly! How come researchers are able to say anything at all about conditions so close to the big bang..?

Swagat: "Yes, the first one second is more challenging and super interesting because lots of interesting quantum mechanical processes and phase transitions occurred during this period.  Using  ground based colliders, we can push to recreate conditions present in the early universe when universe was around a billionth of a second (10^-9 sec). The kind of processes I work on takes us even further back, to about 10^-30 secs or so. Important thing is that the upcoming probes (telescopes, sky surveys etc) of this decade and the next decade will give us information about these earliest moments."

It is quite the irony that the key to some of the biggest questions lies in the physics of the smallest objects we know of. We will continue to collide subatomic particles in giant accelerators, even as we point our telescopes up at the night sky, always in search of more answers, always in search of more questions.

We will continue our conversation in this blog series, and Swagat will help us understand, or rather help us question more intelligently, the bafflingly weird traits of reality.

Mon Sep 14, 2020