How do photon rings in black holes help scientists study the universe?

Photon rings in black holes serve as valuable tools for scientists to study both the black hole's properties and the history of the visible universe. Much like examining tree branches to understand their structure, these rings provide insight into cosmic phenomena. The series of subrings function similar to movie frames, capturing the universe's history from the black hole's perspective. Together, these photon ring layers create a historical record that researchers can analyze to better understand cosmic evolution and structure, offering a unique window into the universe's past.