With consistent, impressive leaps in observational technology, cosmology keeps running into all kinds of issues. One infamous problem is called the Hubble tension. Namely, the two main ways scientists measure the Hubble constant, which represents the universe’s expansion rate, don’t agree. Whether that’s a scientific skill issue or evidence of some unidentified physics, scientists also don’t agree. To be clear, the numerical difference is not that big. The method that uses the cosmic microwave background (CMB), or the leftover radiation from the Big Bang, has the constant at 41 or 42 miles (67 or 68 kilometers) per second per megaparsec (a unit of distance about 3.3 million light-years). The other approach that uses local observations of galaxies and supernova puts it at 45 miles (73 kilometers). But it’s certainly “far larger than can be explained by statistical uncertainty,” as NOIRLab notes in a recent statement on measuring the constant. So for this Giz Asks, we asked the experts for their takes on the Hubble tension. How has the academic debate over the tension progressed in recent times? What would it take to solve this problem, if that’s even feasible? Most importantly, how important is the tension to cosmology as a whole—and what’s really at stake?