A recent study from Yonsei University in South Korea suggests the universe's expansion is slowing down, contradicting the widely accepted Lambda-Cold Dark Matter (LCDM) model which posits an accelerating expansion driven by dark energy. This new research, published in Notices of the Royal Astronomical Society, challenges the prevailing cosmological theory that has been supported by observations of distant supernovae and the concept of dark energy, first proposed by Einstein. The findings present a potential paradigm shift in our understanding of cosmic evolution.