On Friday, April 13, 2029, a rock the size of the Empire State Building will glide across the night sky closer to Earth than our geostationary satellites, visible to the naked eye across Europe, Africa, and Western Asia. This deep dive tells the full story of 99942 Apophis, from its discovery at Kitt Peak in June 2004 to the Christmas scare that December, when calculations showed a 1-in-37 chance of impact and pushed the asteroid to an unprecedented level 4 on the Torino scale.

We trace how archival images from March 2004 shrank the cone of uncertainty, why the 2029 flyby created the nightmare of sub-kilometer gravitational keyholes leading to 2036 and 2068, and how the Yarkovsky effect, a thermal push of about 170 meters per year, complicated every prediction. We finish with the 2021 global stellar occultation campaign that cleared Apophis ...