The Hitchhiker pilot
4°20′
Hitchhiker’s Guide radio pilot produced 28 June 1977. Elon Musk’s birthday. 69 days after 4/20. Mercury at 4°20′ Cancer that day.

PhotoRamaCC BY-SA 3.0 FR
The radio pilot was produced on 28 June 1977. That is Elon Musk’s birthday. Twenty April plus 69 days is 28 June. He said so in public. Mercury prints 4°20′ Cancer on the same civil day. Three true things. Noticed together afterward.
What it supports
Pan Macmillan names 28 June 1977 for the pilot. His own line: I was born 69 days after 4/20. Astro-Seek particular-degree return, Mercury 4°20′ Cancer, 1977. Dated speech, a production date, and a sky print. Doors stay separate.
What it does not
Not proof the BBC set the date by a birthday or by Mercury. Not Towel Day. Not the 1979 book. Not cazimi.
ExactnessApproximate
Form4°20′
Unit°
Strengthattested
When1977-06-28