Astral Odyssey: Thesis Journeys Part 6

 In a thought-provoking interview, Vasudev Mittal delves into the intriguing realm of modern cosmology, focusing on the testing of the Cosmological Principle—the assumption of the universe's isotropy and homogeneity at large scales. His thesis applies Bayesian statistics to scrutinize whether the early and late universe agree on isotropy, drawing from renowned cosmologist Jim Peebles's insights

1.     What was your thesis topic ?

Modern cosmology is based upon the assumption that our universe is homogeneous and isotropic at the largest scales, an ansatz which is dubbed as the Cosmological Principle. However, these is no a-priori reason to assume this. My thesis work involves testing this principle by putting isotropy to the test. I apply Bayesian statistics to check if the early and late universe agree in their notion of isotropy. You can read Jim Peebles’s Anomalies in Physical Cosmology, section 3.2.3 for a detailed overview of the problem.

2.     Why did you choose ?

This is one of the hottest topics in modern cosmology. Recent results have deduced that the evidence for an anisotropic universe is ~5.7σ! (quite high). This has to be refuted or verified. So, I thought that I should work on this problem.

3.     What did you like about it?

The best thing about this problem is that its open to discussion and almost everyone working in the domain knows about this problem. So, it’s a good conversation starter. Also, it can open interesting research avenues for the avid researcher.

4.     Who was your guide ?

Prof. Geraint F. Lewis.

5.     Was astro always the plan?

Yes! My first exposure to Astro was through the show Cosmos by Neil deGrasse Tyson. After that, I got my copy of A Brief History of Time in 5^th class. At that time, I didn’t understand it at all, so I waited for 7 years till I finished my school. By that time, I had enough knowledge of Physics to understand what the book was all about. I guess, it was partly that wait of 7 years and partly the book which brought me into this field.

6.     Internship done in this field ?

I have been working on my thesis topic since 2022. My first project was with a research group working on this problem. Then I followed up on it in 2023 through a DAAD-WISE fellowship. Finally, I did my thesis in this topic under Prof. Lewis.

Apart from this problem, I have also worked as a Science Academies Summer Research Fellowship 2021 on Dark Energy and on two body problem in summer 2020 project under Prof. Bagla in IISER Mohali.

7.     How did you get interested?

Well, it’s an interesting and pressing problem, that was enough for me to convince myself to work on it.

8.     What are the prerequisites for this field ?

A curious mind will do the job. Any research topic in general, does not have any prerequisite. You should have an open mind, and should learn things that you need as you go along. That’s how we make progress. This is equally applicable to all fields.

9.     Any mistakes that you have done , and would recommend the juniors to avoid?

Not a mistake, but a general advice. Scientific community in general has multiple opinions on a research problem. In fact, there are very few things on which almost everyone agrees. Its important to stick to your belief about any open question, and at the same time, be open to the opinion of others as well. It will help you in progressing in science.

10.  What are your future plans?

Joining academia.

--Avni (MS22)