A new map of the early Universe has reinforced a long-running conundrum in astronomy over how fast the cosmos is expanding. The data — collected using a telescope in Chile’s Atacama Desert — back up previous estimates of the Universe’s age, geometry and evolution. But the findings clash with measurements of how fast galaxies are flying apart from each other, and predict that the Universe should be expanding at a significantly slower pace than is currently observed…
The European Space Agency’s Planck telescope mapped the entire CMB sky from 2009 to 2013 with unprecedented precision, and its observations are considered the gold standard of CMB cosmology. The ACT data now vindicate Planck’s findings and produce a very similar value for the Hubble constant.
But neither result matches direct measurements of the Hubble constant — a discrepancy that has become known as the Hubble-constant tension. Astronomers who use the brightness of particular types of stars and supernova explosions, collectively called standard candles, to calculate the expansion rate find that galaxies rush away from each other roughly 10% faster than the CMB maps predict.
Many researchers had hoped that as techniques became more accurate, the gap would shrink. Instead, narrowing error bars for each type of study have only made the inconsistency more significant.Davide Castelvecchi, “Mystery over Universe’s expansion deepens with fresh data” at Nature
We live in an age when science just isn’t giving us Answers any more.