New measurement of universe's expansion worsens 'Hubble trouble'

The most accurate observation of distant stars that periodically change in brightness may deepen the "Hubble tension," a problem with the rate at which the universe expands. The observation confirms a disparity that exists between the two major methods of measuring how fast the universe is expanding, conforming with one but not the other. Researchers used data collected by Europe's Gaia spacecraft to study Cepheid variable stars, which pulsate in a regular manner, providing a way of accurately measuring cosmic distances. The cosmic distance ladder is also used to measure the expansion rate of the universe, known as the Hubble constant.