Researchers Father Richard D’Souza SJ and Eric Bell determine that the Milky Way had a sibling, which was devoured by the Andromeda galaxy almost two billion years ago.
Richard D’Souza comes as a surprise. To begin with, he's an ordained Catholic priest with Jesuit Mission. The Goa native is also the scientist who recently made a path-breaking discovery about M32p, a long-lost galaxy considered to be a sibling of the Milky Way, our galaxy.
Father Richard D’Souza SJ and Eric Bell, researchers at the University of Michigan, recently used computer models and simulations to reveal the dark past of Andromeda(M31), a spiral galaxy approximately 780 kiloparsecs (2.5 million light years) from Earth, and the nearest major galaxy to the Milky Way.
Their research, which was published in Nature Astronomy last week, revealed that about two billion years ago, Andromeda was guilty of celestial cannibalisation.
How and why? Research has shown that if two galaxies are drawn together by a gravitational pull, they often stand the risk of colliding. In case this happens, the larger galaxy tends to subsume the smaller one. Andromeda is the largest galaxy of the Local Group (Milky Way is also a part of this), and is believed to have cannibalised several small galaxies over the years.
The new research shows that Andromeda destroyed M32p, leaving behind a trail of cosmic debris as evidence. The new findings propose that “the undestroyed core of the cannibalised galaxy went on to form M32 [Andromeda’s intriguing satellite galaxy]”. The findings have evinced attention for their potential to change the human understanding of how galaxies merge - and evolve - over time.
Richard, the lead author on the paper, hails from Mapusa, Goa. He studied at St Xavier’s College, Mumbai, and is doing his post-doctoral research at the University of Michigan. The Jesuit priest is a staff member of the Vatican Observatory, an astronomical institution supported by the Roman Catholic Church.
He believes that the enormous Andromeda has swallowed many small galaxies. “Over the course of its lifetime, Andromeda is thought to have merged with hundreds of smaller galaxies,” he told The Times of India. These smaller galaxies are destroyed in the process, leaving behind a trail of stellar debris around the main galaxy, called its stellar halo,” he added.
He reiterated, in an interview with Scroll, why this finding could “alter the traditional understanding of how galaxies evolve”. “The Andromeda galaxy is moving towards the Milky Way at about 110 km/s, and will eventually collide with it in about four-five billion years. Eventually, our galaxy will be part of the stellar halo around the Andromeda galaxy. Moreover, since both galaxies are large and comparable in size/mass, we suspect that Andromeda may not survive the collision, and may transform into an elliptical galaxy,” he said. But he cautioned that it’s also possible that in the same time frame, the sun could turn into a red giant star and make the earth inhabitable!
In an interview to The First Post on the intersection of science and faith in his life, he says he aims to keep the two apart but it “does not actually work out”. “I often find myself preaching about the hard process of research and the spiritual lessons one can draw from it. When I am down and disappointed in my research, I find myself praying for inspiration and for God’s help. My spiritual life and my research work interweave seamlessly,” Richard ends.