Scientists are testing a novel way to measure cosmic expansion using time delays in gravitationally lensed quasars. Their ...

The universe’s expansion rate was supposed to be a solved problem, yet the latest high precision map of the early cosmos has pushed one of modern astronomy’s sharpest conflicts back to center stage.

The universe is expanding, but astronomers still cannot agree on exactly how fast. That mismatch, known as the Hubble tension, has turned a seemingly simple number into one of the biggest headaches in ...