Alexandra Terrana


PhD Candidate, Physics & Astronomy

Vanier Scholar

My Research

I work in the fascinating field of theoretical cosmology, studying the mathematical models that are used to describe the evolution of the universe on the largest scales. One of the key ingredients in determining how structure forms in our universe is the force of gravity. My current project aims to determine the cosmological implications of modifying our current theory of gravitation in the hopes of solving some of the major outstanding mysteries in modern physics, such as dark energy.

Einstein’s theory of general relativity is widely accepted as the correct theory of gravity, but it is known to have problems describing our universe on very large scales. To make the theory match our observations, physicists need to invoke hypothetical dark matter and energy components that must make up 96% of our universe. After decades of dedication towards understanding this dark sector, it largely remains a mystery. An exciting direction of research that aims to solve this puzzle is to modify our theory of gravity so that we can accurately model the universe without dark matter or dark energy. This proves to be very challenging to do, since the new theory must be mathematically consistent, and able to describe all of the physical phenomena we observe. “Massive gravity” is one of the most successful attempts to modify gravity to date, but a lot is unknown about its predictions for time-dependent phenomena, such as gravitational collapse. By analyzing the time-dependent equations in massive gravity , I will determine the ultimate viability of the theory as a description of nature.

Graduate Studies at York

The main reason I chose York University was to work with my supervisor Dr. Matthew Johnson. His research interests exactly match my own, and he does a lot of exciting and innovative work in theoretical cosmology. In addition, he is a great teacher and very enjoyable to work with. I look forward to continuing our research and doing some great work together. The cosmology sector in the physics department here is quite small, so I am glad to be part of this growing group as we attract more faculty and students to this exciting field of research at York.

After my first year here, I can say that I am very impressed with the graduate program at York. I have felt welcome and motivated to succeed. The most impressive aspect has definitely been the exceptional faculty. There are so many excellent teachers who are enthusiastic and passionate about their work. They are also helpful and encouraging, as they truly want their students to excel. Also, being a large school, there are many great programs to choose from in all disciplines, and a lot of opportunity to get involved in the campus community, so you really can’t go wrong!