James Webb Just Measured the Edge of the Observable Universe—And the Number It Found Breaks Cosmolog

The observable universe is 46.5 billion light years across. Most people think it should be 13.8 billion, the age of the universe in years. They are wrong, and the real number is only the beginning of what James Webb has been finding. In this video, Brian Greene walks through the specific observations that are generating quiet alarm in the cosmological community. Galaxies in the early universe that are too massive by factors of ten to a hundred. Large-scale structures extending billions of light years that the standard model says have a one in fifty thousand chance of existing. A Hubble tension that James Webb has sharpened rather than resolved. And new DESI data suggesting dark energy may not be constant. Taken individually, each anomaly can be explained away. Taken together, they form a pattern that is becoming increasingly difficult to ignore. Lambda-CDM, the standard model of cosmology that has explained everything for thirty years, may be missing something fundamental about the structure of the universe at its largest scales. Greene explains what that something might be and what it would mean if the map we built of the cosmos turns out to be incomplete. Subscribe to Brian Greene Universe for cosmology at the edge of what the data currently allows us to say.