Gravity Seems Holographic. What Does That Mean for Reality?

Physicists have discovered that gravity appears to be "holographic," meaning the entire contents of a three-dimensional space can be determined by measuring only its two-dimensional surface—a finding that suggests gravity and quantum mechanics may be fundamentally connected and that space itself might be an illusion. This breakthrough, formalized through the AdS/CFT correspondence discovered in the late 1990s, has become the most cited theoretical physics work of recent decades and helped solve a major puzzle about black holes, though physicists still grapple with its full implications for our understanding of reality.