Debate over the universe’s expansion rate may unravel physics. Is it a crisis?
Scientists tackle disagreements about the Hubble constant
![expanding universe distance ladder](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2019/07/072619_ec_expanding-universe_feat.jpg?fit=1030%2C580&ssl=1)
EXPANSION FACTIONS The universe is expanding — but how fast? Some measurements using a technique known as a “distance ladder” (illustrated) disagree with estimates from the early universe.
JPL-Caltech/NASA