COSMO-BRIDGE Cosmology in a Crisis: Bridging the gap between the cosmic past and future

In cosmology, there is a highly significant and rather mysterious discrepancy between different measurements of the expansion rate of the Universe: Apparently, the Universe is expanding faster today than expected from the standard, and otherwise very successful, cosmological model. Intriguingly, this may call for ‘new physics’, such as an accelerated expansion within the first 400.000 years after Big Bang. But are we sure we got the measurements right? To solve the mystery, I propose to develop a new method for measuring accurate distances to supernovae (cosmic thermonuclear explosions). These distances are used to measure the expansion rate in the local Universe. As a proof of concept, I will implement the method and measure distances to 200 supernovae with the Danish 1.5 meter telescope. By the end of the project, if successful, the method will be applied to the thousands of supernovae expected to be discovered with the Vera C. Rubin Observatory Legacy Survey of Space and Time, starting in 2026.