A recent intergalactic discovery making headlines around the world has an Indian connection. Earlier this week, it was widely reported that scientists Richard D & # 39; Souza and Eric Bell of the University of Michigan concluded that the Milky Way once had a sibling devoured by the neighboring Andromeda galaxy about two billion years ago [196592002TheresultswerepublishedonJuly23inthe Nature Astronomy Journal and have drawn attention to their potential to change our understanding of how galaxies unite and evolve over time.
When two galaxies are contracted by gravity Pull, they stand the risk of collision. In such a case, the larger usually subsumes the smaller entity. Andromeda, the largest galaxy in the Local Group, which includes the Milky Way, has long been believed to have devoured several small galaxies over the years. Using computer simulations, D & # 39; Souza and Bell concluded that one of the galaxies Andromeda merged with was actually a huge one, the third largest in the Local Group after the Milky Way.
The researchers suggested that the stars of this crushed galaxy surrounded the Andromeda, giving it the outer, weak stellar halo and its mesmerizing satellite galaxy M32. Scientists have long been trying to decipher how M32 was formed, as it is a rare compact elliptical galaxy (unlike the Milky Way, which is spiraling), which is rich in stars. The new findings indicate that the undisturbed nucleus of the cannibalization galaxy forms M32
In media reports described as a sister or sister of the Milky Way, the lost galaxy was called M32p. The results are interesting not only because they show that the core of M32p survived the collision, but also that the Andromeda disc remained intact despite being fused with such a large galaxy. This contradicts the traditional scientific belief that collisions between entities of this size would dramatically affect the structure of the surviving galaxy.
D & # 39; Souza, the main author of the newspaper, is from Goa, India, where his family is still alive. He is doing his postdoctoral research at the University of Michigan. D & # 39; Souza is also a Jesuit priest and collaborator of the Vatican Observatory, an astronomical institution supported by the Roman Catholic Church.
D & S Souza has a long and illustrious academic career and has studied an interesting mix of subjects. He was born in Pune in 1
In an interview with Scroll.in D & # 39; Souza talks about his interesting academic graphics, how his religious and scientific activities inform each other and what his discovery means for the future of the Milky Way. Excerpts:
How would you explain to a layman your recent discovery?
My research focuses on how galaxies grow through mergers. Throughout her life, it is believed that a galaxy like Andromeda, our next big neighbor, has merged into hundreds of smaller galaxies because of its gravitational pull. These smaller galaxies are destroyed by the tidal forces of gravity, leaving a trail of stellar debris (such as "crumbling") around the main galaxy called the stellar halo.
By studying the stellar halo of a galaxy, I have developed a technique that suggests the size of the largest galaxy that was destroyed. This is similar to guessing what a little kid ate after seeing the crumbs and mess on the floor!
Observations over the past decade have shown that Andromeda has the largest stellar halo for any galaxy of its size. We've realized that Andromeda must have connected to a really big galaxy to build such a big star halo. We can best understand this through a business analogy. Like companies, galaxies grow through mergers. Now a company can grow moderately by merging with other smaller companies. But if a big company wants to get a big boost in growth, it has to negotiate a merger with another, significantly larger company. Based on observations of the large stellar halo of the Andromeda galaxy, we concluded that not so long ago it coincided with a significantly large galaxy (1/4 of its size).
How many years was this result in the making? And what was the nature of your research work before that?
We started thinking about this project about a year and a half ago! At this time last year, we started writing it, and we were mostly done within six months. The review process of the Nature Journal lasted another 6 months, before I concentrated on the depth observations of stellar haloes of more distant galaxies for my PhD at the Max Planck Institute in Germany.
How does this discovery change our understanding of the universe? The University of Michigan press release says it may "change the traditional understanding of galaxy evolution." Could you explain that in more detail?
Destroy the slices of galaxies that convert them into elliptical spheroidal galaxies. We now know that the slice of the Andromeda galaxy has survived this particularly large fusion, though we do not know exactly why. This realization leads to a fundamental paradigm in our understanding of galaxy evolution. One thing we can take away is that the disks of galaxies are more resistant than previously thought. We hope that this finding will motivate further investigation to understand the circumstances under which the slices of galaxies survive such large interactions.
What is the significance of the fact that the Milky Way had a different sister galaxy? How is a galaxy called a sibling galaxy?
The Andromeda and the Milky Way are relatively close together and are the largest members of the galaxy's "local group". Astronomers have long studied the local group, including their smaller members, thinking that they knew their local neighborhood quite well. We now know that there was another galaxy out there (which we call M32p), which was almost half the size of the Milky Way and was destroyed by Andromeda. That's a complete surprise! This makes M32p the third largest member of the Local Group. The next smallest member, the triangulum galaxy, is at least eight times smaller than the Milky Way. In fact, M32p was finally found a long lost sibling. We joked that it was "the missing family member" nobody wanted to talk about.
Could the study of the M32p bring more light into our galaxy?
The Milky Way currently has a large satellite galaxy called the Great Magellanic Cloud, which will merge with it for about one to two billion years. Although the Large Magellanic Cloud is much smaller than M32p, astronomers were worried that the disc of the Milky Way would survive the merger. Andromeda and M32p have now taught us that the Milky Way will survive this merger.
Some scientists have talked about the likelihood that Andromeda will collide with the Milky Way in billions of years. Does Andromeda's consumption of M32p in any way deliver more?
The Andromeda galaxy is approaching the Milky Way at about 110 km / s and will collide with it in about four to five billion years. Eventually, our galaxy will be part of the star galaxy around the Andromeda galaxy. Since both galaxies are large and comparable in size / mass, we suspect that Andromeda could not survive the collision and turn into an elliptical galaxy. So is the universe and how do the gravitational forces work? We need to remember that within a similar timeframe, our own Sun will become a red giant star, expanding and making the land habitable. That can be a much more immediate concern!
You have Yes, the study of philosophy and theology gave me the opportunity to broaden my thinking as I did of science, theology, philosophy and physics, this is an unusual and intriguing range of topics Theology has helped me think about deeper issues that motivate all of us: where do we come from, where do we go and what is the meaning of life? enjoy the science, she is a little restrictive and limited in her approach, philosophy and theology equipped me with tools to handle a wider range of problems and problems thinking and thinking.
The Catholic Church has historically taken an attitude is somewhat contrary to sc experience. It is unusual, if not unknown, to have scientists who are also priests. How do your religious and scientific beliefs interact?
It is rather unfortunate that historically the Catholic Church has made a number of mistakes in the sciences, especially when it saw its power and doctrine threatened. However, it must also be stressed that the Catholic Church has contributed to its development in its own way through the development of universities in Europe, but also through the number of its clergy who have been actively involved in the sciences over the centuries. This part of the story is omitted!
I see no fundamental contradiction between my religious and scientific beliefs. They actually go hand in hand. My religious beliefs tell me that God has created the world as good for some laws. This basic assumption assures me that the laws of nature are constant and can actually be studied. For this reason, the sciences thrived in the West, unlike other cultures in which the gods and thus the understanding of reality were more moody and moody. For me studying the universe helps me to learn more about its creator. Therefore, for me, studying astronomy, stars and galaxies is the ultimate form of worship.
What made you study religion and become a priest?
I studied at a Jesuit school in Goa and was fascinated by the local Jesuits. There the roots of my calling began. Her long history of working in the sciences has been a big draw for me.
Where does astronomical research stand today in India? And do you have plans to return after completing your postdoctoral research in Michigan?
There are a number of excellent astronomical centers in India today, especially in Pune and Bangalore. Traditionally, research in our country has been more theoretical, but that's changing fast. Observational progress typically requires greater investment, especially in terms of money and resources. Optical astronomy today is driven by new observational data, which in turn depend on having access to the right telescopes, instruments and resources. I think our Indian scientists could make much more progress if the government invests more in instruments.
After my postdoc stay in Michigan, I plan to return to the Vatican Observatory. I am open to opportunities to conduct research and to collaborate with scientists in India!