"The Changing Nature of the Hubble Constant"

The Hubble constant, which describes the rate of the Universe's expansion, is not truly constant over time. While it appears constant to us at a given moment, it changes as the Universe evolves due to the presence of different forms of energy, such as dark energy. The expansion rate drops as the Universe grows, with the Hubble constant asymptoting to a finite, positive value determined by dark energy density. Although individual objects appear to accelerate away from us, the expansion rate itself is still decreasing. This challenges the idea of a constant expansion and highlights the complex nature of the Universe's evolution.