Abstract:
Abstract: The Event Horizon Telescope has produced the first horizon-scale images of black
holes at millimeter wavelengths. These images probe how black holes interact with their
surroundings, how plasmas behave under extreme conditions, and how spacetime shapes the
appearance of matter near an event horizon. I will review existing images, summarize what
we have learned from them, and discuss the main theoretical challenges in interpreting
them. I will then look ahead to black hole movies that trace the dynamics of the emitting
near-horizon plasma, multi-frequency imaging, and the higher angular resolution that could
be accessed with a space-based antenna.