|The woo is out there|
|Aliens did it and ran away|
Black triangles are a type of UFO that look like, well, black triangles with or without lights on their tips. The type seems to have become popular in the 1980s and 1990s. By some coincidence, this is about the same time when vaguely triangular stealth aircraft like B-2 and F-117 were tested and commissioned.
Most likely there's no single reason explaining all cases. Nevertheless, here are several possible reasons (assuming that the observer actually saw something triangular):
- Any group of three lights in the dark sky may be interpreted by an observer as a single, triangular craft, even if it's actually three aircraft flying in a formation or something entirely else.
- Misidentified stealth aircraft (the military would be very happy indeed to have their secret stuff "identified" as an
alien craftUnidentified Flying Object)
- A trio of first or second generation Naval Ocean Surveillance System (NOSS) satellites - US spy satellites that fly in a triangular formation.