If you’re confused by modern cosmology, you’re not alone. Cosmologists themselves are confused, and two new results, using very different methods, add to their collective bewilderment. The results are measurements of how fast the universe is expanding, known as the Hubble constant. In recent years, astronomers keep finding strangely different answers to this basic question.In much-anticipated research released Tuesday and set for publication in The Astrophysical Journal , one group, led by Wendy Freedman of the University of Chicago, found that our cosmos is expanding at a rate of 69.8 kilometers per second per megaparsec, where one megaparsec equals 3.26 million light-years.But in another study published last week on the arXiv , an open-access website, an international consortium known as H0LICOW led by Kenneth Wong of the University of Tokyo and Sherry Suyu of the Max Planck Institute in Germany, measured the universe’s expansion rate at 73.3 kilometers per megaparsec.The results are close, but they’re not the exact match that would make everyone happy. Both teams have essentially laid down new markers in a field that has been rife with controversy for decades. And they feed into a growing tension between groups that use different methods to measure cosmic expansion.The stakes are high. Small changes to the Hubble constant affect science’s best estimate for the age of the universe by hundreds of millions of years. And if astronomers can nail down the Hubble constant to everyone’s satisfaction, they could help reveal the nature of the mysterious dark energy that is causing cosmic expansion to accelerate.

NASA, ESA, W. Freedman (University of Chicago), ESO, and the Digitized Sky Survey