An international team of astronomers has produced the most precise direct measurement yet of how fast the Universe is expanding today, strengthening evidence behind one of modern cosmology’s biggest puzzles.

The study, led by the H0 Distance Network (H0DN) Collaboration, reports a highly precise value for the current expansion rate by combining multiple independent measurement techniques into a single framework. The team reports the universe’s current expansion rate at 73.50 kilometers per second per megaparsec, with an uncertainty of ±0.81.

Dr. Syed Ashraf Uddin, Associate Professor of Physical Sciences and a member of the core group of the Center for Astronomy, Space Science and Astrophysics (CASSA) at Independent University, Bangladesh (IUB), has contributed to the study as part of the global H0DN collaboration. The study, titled “The Local Distance Network: A community consensus report on the measurement of the Hubble constant at ∼1% precision”, has been published in Astronomy & Astrophysics. Dr. Uddin has been involved in advanced research on measuring the rate of expansion of the universe for several years.

Astronomy & Astrophysics is a leading international peer-reviewed journal, publishing original research across areas such as cosmology, stellar physics and planetary science. Published by EDP Sciences and supported by a consortium of European research institutions, it is widely regarded as one of the top journals in the field, known for its rigorous review standards and global scientific reach.

The finding of this study is significant in the context of the long-standing Hubble tension – a growing mismatch between measurements of the universe’s current expansion rate and estimates based on observations of the early universe, particularly the Cosmic Microwave Background.

Dr. Uddin said, “For years, scientists have debated whether this gap is due to hidden errors in measurement techniques or points to gaps in existing theories. By showing that multiple independent methods converge on the same higher value, the new study makes it harder to attribute the discrepancy to a single flawed approach and strengthens the case that the tension may reflect deeper, unresolved physics.”

Rather than relying on a single “cosmic distance ladder,” the team adopted a broader approach by building a “distance network.” This method connects different ways of measuring cosmic distances – such as variable stars, supernova explosions and galaxy properties – into a unified system. By accounting for overlaps and shared uncertainties between these methods, the researchers were able to cross-check results and produce a more robust and transparent estimate.

The collaboration brought together nearly 40 researchers from diverse methodological backgrounds, including scientists who have previously worked in separate teams using different techniques to measure the expansion rate. This cross-method participation ensured that no single approach dominated the outcome and that the final result reflected a broad, community-driven consensus within the local measurement field.

Measuring the universe’s expansion has historically relied on several independent techniques. Some use pulsating stars to gauge distances to nearby galaxies, others rely on exploding stars as standard markers across vast cosmic scales, while additional methods use properties of galaxies themselves.

“Differences in calibration, data quality and underlying assumptions have led to slightly different results over time. The new study addresses these variations by combining all major methods in a consistent framework and showing that, when treated together, they produce a stable and mutually consistent result,” said Dr. Uddin.

“This work is important because it shows that the higher expansion rate we observe locally is not dependent on any single method,” said Dr. Uddin. “When multiple independent approaches point to the same result, it strengthens our confidence that the discrepancy we see is real and not simply a measurement issue.”

He added that the study provides a clearer foundation for future research. “By building a transparent and flexible framework, we are enabling the scientific community to test new data and refine the measurement further, which is essential for understanding whether new physics may be required.”

Dr. Khan Muhammad Bin Asad, Assistant Professor of Physical Sciences and Director of CASSA at IUB, said the university’s involvement reflects its growing engagement with global scientific research. “Through CASSA, we have been working for several years to connect researchers in Bangladesh with the international astronomy and astrophysics community, while also creating opportunities for students and young researchers to participate in cutting-edge work,” he said.

About CASSA

The Center for Astronomy, Space Science and Astrophysics (CASSA) at Independent University, Bangladesh (IUB) is dedicated to advancing research, education and public engagement in astronomy and astrophysics. The centre has recently installed a Transient Array Radio Telescope (TART), the first such telescope in the entire northern hemisphere, with mainly in-house engineering fabrication capacity to support observational research and student training. The center also works to build international collaborations, including partnerships with astronomers and astrophysicists of Bangladeshi origin working in universities and research institutions around the world, contributing to the development of the field in Bangladesh.

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