By using galaxies as giant gravitational lenses, an international group of astronomers using the Hubble Space Telescope have made an independent measurement of how fast the Universe is expanding. The newly measured expansion rate for the local Universe is consistent with earlier findings. These are, however, in intriguing disagreement with measurements of the early Universe.
When Edwin Hubble discovered nearly 100 years ago that the universe was uniformly expanding in all directions, the finding was a big surprise. Then, in the mid-1990s, another shocker occurred: astronomers found that the expansion rate was accelerating, perhaps due to “dark energy.” Now, the latest measurements of our runaway universe suggest that it is expanding faster than astronomers thought.