Goan Jesuit priest Fr. Richard D’ Souza who is the newly elected director of the Vatican Observatory, was down in the state recently. NT NETWORK caught up with him
ARPITA SRIVASTAVA
Could you tell us about your days in Goa, especially in Britto’s, your alma mater?
We moved back to Goa from Kuwait, when I was 12. I continued my education from Class 8 onwards at St. Britto High School and later at St. Xavier’s Higher Secondary. I enjoyed my time at St. Britto High School – where I made a lot of friends and learned a lot about the world. It helped me to think critically about life and the world.
How did you come to become an astronomer?
I was always interested in physics and science right from a young age. When I was in St. Britto’s, we used to go for camping trips far away from the cities, where at night, one could see the night sky. It was only much later when I was studying in university in Germany that I seriously started considering astronomy.
Could you tell us about the discovery you made – the long-long sibling of our galaxy – a few years ago?
One of my primary research questions is to understand how the present-day properties of galaxies are influenced by the merging of galaxies. During its lifetime, a galaxy, like our own Milky Way, merges with thousands of smaller galaxies. To understand how these mergers affected the present-day properties of our galaxy, one must infer the past mergers of a galaxy, just as an archeologist would do to retrace the past history of an object. One does this by studying the faint light present in the outskirts of the galaxy, which is very difficult to observe. But this outer light contains information about the galaxy’s past.
Through my research, I was able to demonstrate how it was possible to constrain the mass and the time of the merger of the largest satellite galaxy, which merged with the main galaxy. We applied this methodology to our nearest neighbouring Andromeda Galaxy, and inferred that it must have merged with a large galaxy about two billion years ago, which was half the size of the Milky Way. We postulated that such a large galaxy once existed and was devoured by the Andromeda Galaxy. We also postulated that the remnant of this galaxy still exists today in the form of the enigmatic galaxy M32, which has defied explanations till now. Hence, the large galaxy that was destroyed was named “M32p,” or the progenitor of M32. One of the hints that led us to identify M32 as a possible remnant galaxy was its high density, much higher than the cores of most galaxies.
From your research, what do you infer about the universe and its future?
We know that our star will live for another five billion years – becoming a red giant star and consuming the Earth. In the same time frame, our galaxy, the Milky Way will crash with the Andromeda Galaxy. While most of the stars will pass through each other, the gas in each of the galaxies will compress forming new stars, which will emit a lot of harmful radiation for life.
On the other hand, scientists have discovered since 1990’s the existence of a mysterious force – called Dark energy – which is responsabile for the accelerated expansion of the universe. This will most like result in a likely “death”, also known as the Big Freeze, where the universe becomes cold, dark, and empty over trillions of years as galaxies move too far apart for stars to be visible and all stars eventually die out.
