One of the most puzzling discoveries in astronomy is finding supermassive black holes - each weighing more than a billion times our Sun - in the very young universe, less than a billion years after the Big Bang. It's like finding a 40-year-old person who's only 4 years old - it challenges our understanding of how these cosmic giants could grow so massive so quickly.

The James Webb Space Telescope has recently deepened this mystery by discovering even more unexpectedly massive black holes in the early universe. These early black holes show interesting patterns: they display certain telltale signs of active feeding (broad emission lines in their light spectrum), but they're surprisingly dim in X-ray light. This unusual behavior suggests they might be consuming matter at extraordinary rates, beyond what we typically expect is possible.

To understand these cosmic extremes, we study how matter falls into black holes through structures called accretion disks. In most black holes, these disks are thin and flat, like a pizza. However, when black holes feed very rapidly, their disks puff up like a bloated pizza, creating what we call a 'slim disk' (see Fig. 1) This different structure changes how we see the black hole from Earth - depending on our viewing angle, it can appear unusually dim in X-rays and show other distinctive features.