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The Missile Knows Where It Is...

Jeff7181Cited 11× on HN, 2015–2025
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comedy · general · evergreen · 2015–2025 on HN

A short clip of the famous Hitchhiker-style circular narration of a missile guidance system explaining how it knows where it is by knowing where it isn't. It is a deadpan bit of technical-sounding absurdity about subtraction and navigation.

HN commenters post it as an obligatory joke reply whenever threads touch on missiles, GPS, or circular reasoning.

11 comments from Hacker News

@neuralkoi2025-11 · in “The Pentagon Can't Trust GPS Anymore”

I wonder if this changes the old adage, now that the missile knows where it is at all times. [0] [0] ▶ this video

@jazzyjackson2024-08 · in “Robot Dog with Gun Turret for Hunting Aerial Drones Being Tested by Army”

predicting trajectory of a projectile is what computers were first made to do, at least if you count ENIAC as the first, and the Apollo Guidance Computer not long after (the missile knows where it is at all times, it knows this because it knows where it isn't... [0]) as it happens the projectiles have minds of their own now so to predict trajectory will require theory-of-mind shooting down fast moving drones might just be the path to self-awareness in the machine world, "if I were a drone, what action would I take in that situation..." [0] ▶ this video [0.b remix] link

@bombcar2024-01 · in “The Miele Dialog: cook a fish in ice without melting the ice”

It's a reference to ▶ this video > The missile knows where it is at all times. It knows this because it knows where it isn't. By subtracting where it is from where it isn't, or where it isn't from where it is (whichever is greater), it obtains a difference, or deviation. The guidance subsystem uses deviations to generate corrective commands to drive the missile from a position where it is to a position where it isn't, and arriving at a position where it wasn't, it now is. Consequently, the position where it is, is now the position that it wasn't, and it follows that the position that it was, is now the position that it isn't.

@H8crilA2023-11 · in “Rockwell Retro Encabulator [video]”

It's also important to know where you are (by knowing where you aren't): ▶ this video There's also a version for when you need that little bit of extra motivation: link

@btown2023-08 · in “A Grumman F11 Tiger Shot Itself Down”

Ah, this happened with bullets, not missiles. Because the missile knows where it is at all times. It knows this because it knows where it isn't. By subtracting where it is from where it isn't, or where it isn't from where it is (whichever is greater), it obtains a difference, or deviation. The guidance subsystem uses deviations to generate corrective commands to drive the missile from a position where it is to a position where it isn't, and arriving at a position where it wasn't, it now is. Consequently, the position where it is, is now the position that it wasn't, and it follows that the position that it was, is now the position that it isn't. ▶ this video