Photographing a black hole requires the magnification needed to see a tennis ball on the Moon from Earth. This episode explains how the Event Horizon Telescope achieved it by linking radio observatories from Mexico, Chile, Hawaii, and Spain to the South Pole through very long baseline interferometry, creating a virtual dish the size of the planet with a resolution of 19 microarcseconds, enough to read the date on a quarter in Los Angeles from New York.

The hosts walk through the atomic clocks that time-stamp every radio wave, the sneakernet of hard drives flown to MIT Haystack Observatory and the Max Planck Institute for Radio Astronomy, the South Pole data trapped in the ice until December 2017, and the 800-CPU correlators that stitch it together. They cover the April 10, 2019 unveiling of M87*, a spinning Kerr black hole of 6.5 billion solar masses, the four quarantined imaging teams using CLEAN and Katherine Bouman’s methods who independently produced the same ring, the May 2022 image of Sagittarius A*, and observations of the blazar 3C 279 and quasar NRAO 530 showing superluminal motion and toroidal magnetic fields.

• Why the distance between telescopes, not the size of any one dish, determines angular resolution
• How petabytes of data made commercial air freight faster than the internet
• Why the shadow of M87* appears about 2.5 times larger than the event horizon itself
• Why a black hole thousands of times smaller than M87* looks remarkably similar near its edge
• How plasma jets can appear to move at 20 times light speed without breaking physics