Is the Universe Expanding?

The video explores the history of astronomical discoveries, focusing on the realization that the universe is expanding. It explains how Vesto Slipher's observation of redshifted light from galaxies led to the understanding that space itself is stretching. Georges Lemaitre and Edwin Hubble further developed this idea, leading to the concept of the Hubble Constant. The video also discusses the accelerating expansion of the universe due to dark energy and concludes with a reflection on the significance of these discoveries.

Explain the concept of the universe expanding and how it differs from the idea of galaxies flying away from each other.

What is the Hubble Constant and why is it important in understanding the universe?