The most accurate observations to date of distant stars whose luminosity changes periodically could lead to a rethinking of the expansion rate of the universe – perhaps solving or deepening a longstanding problem in cosmology. The observation confirms the inconsistency that exists between the two main methods of measuring the expansion rate. The universe reports a new study for one, not the other.

Researchers from the Stellar Standard Candles and Distances group used data collected by the European spacecraft. Gaiato work Cepheid variable starsvibrating regularly and providing a way to accurately measure cosmic distances. The Cepheid star measurement technique complements other methods such as observation-based ones. supernova Type 1a.

The light flux from supernovae, the giant explosions that occur at the end of the lives of massive stars, are so uniform that they are called “standard candles” and form an important part of what astronomers call the “cosmic distance ladder.” The method of measuring the distance to a Cepheid star adds another rung to this metaphorical ladder, and this new study has strengthened that rung.

“We have developed a method that searches for Cepheids belonging to star clusters of several hundred stars, checking whether the stars are moving together in Chumatsky. path”, — study co-author Richard Anderson, physicist at the Federal Polytechnic School of Lausanne (EPFL) in Switzerland, the explanation says.

“With this trick, we can take advantage of the best knowledge of Gaia’s parallax measurements while taking advantage of the increased sensitivity provided by the cluster’s many member stars,” Anderson said. “This allowed us to push the accuracy of Gaia’s parallaxes to their limits and provided the strongest foundation on which to build the ladder of distance.”

The cosmic distance ladder is also used to measure the expansion rate of the universe. Hubble happened. This new recalibration of the Cepheid “step” deepens the problem with the expansion rate of the universe, known as the “Hubble stress.”