On January 5, 2025, Syed Ashraf Uddin, a faculty, astronomer and astrophysicist from the University of South Carolina, USA, delivered a lecture at the 3rd Colloquium of the Center for Astronomy, Space Science, and Astrophysics (CASA) at Independent University, Bangladesh (IUB).
The colloquium took place in the DMK Building Lecture Gallery. Approximately 30 undergraduate students from IUB and several other universities in Dhaka attended the colloquium, either in person or online.
Ashraf Uddin, who is an associate member of CASSA, was received by Prof. Dr. M. Arshad Momen, Director of the Office of Graduate Studies, Research and Industrial Relations (GSRIR); Dr. Mustafa Habib Chowdhury, Associate Professor and Head of the Department of Electrical and Electronics Engineering; Prof. Amin Ahsan Ali from the Department of Computer Science and Engineering; and Dr. Jewel Kumar Ghosh from the Department of Physical Sciences.
The main topic of Ashraf Uddin's discussion was determining the Hubble Constant, which is the rate of expansion of the universe, through the observation of Type 1a supernovae. For the convenience of students, he divided the talk into two parts.
In the first part, he discussed the fundamentals of observational cosmology, and in the second part, he detailed his work on the Carnegie Supernova Project as an example. He placed particular emphasis on the “known unknowns” of cosmology.
Astronomer Syed Ashraf Uddin's lecture explored three "known unknowns" in cosmology: dark matter, dark ages, and dark energy. He highlighted Vera Rubin's work on galactic rotational anomalies that revealed dark matter, discussed the universe's "dark ages" when galaxies formed, and emphasized the mystery of dark energy, which drives the universe's accelerating expansion. He explained that only 5% of the universe consists of known matter, while 27% is dark matter and 68% is dark energy.
To measure the Hubble constant, he described the cosmic distance ladder, from parallax measurements to Type Ia supernova. He addressed the unresolved "Hubble tension" where three methods yield differing results for the universe's expansion rate. Ashraf Uddin detailed the Carnegie Supernova Project, which measured the Hubble constant across six visible and three infrared bands, reducing uncertainty to 1.5% by combining multiple methodologies.
He emphasized future plans, including AI-driven analysis for next-generation observatories like the Vera C. Rubin Observatory. After the lecture, Ashraf Uddin praised IUB's contributions to astronomy, including its undergraduate specialization and research facilities, and expressed interest in further collaboration.
On January 7, he met IUB Vice Chancellor Prof. M. Tamim, lauding the university's role in advancing astronomy in Bangladesh and expressing hopes for continued progress.
BDST: 1950 HRS, JAN 20, 2025
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