One of the most contested issues in astrophysics is our understanding of the Universe’s expansion. Adam Riess discusses why there is disagreement and what might resolve it. The post How Fast Is the Universe Really Expanding? first appeared on Quanta Magazine
One of the biggest mysteries in cosmology seems to keep getting bigger. Astronomers have known since the 1930s that the universe is expanding, but in the 1990s, the discovery that this expansion is accelerating rather than slowing down came as a huge shock to the field. Something had to be driving that acceleration, and dark energy was proposed as the cause. What began as a seismic shock in…