A Japanese team of researchers are working on a positioning system using muons, which could be used in places where GPS signals can’t be received (such as underwater or underground).
The article discusses many of the challenges and reasons why it currently isn’t ready for practical applications. But it certainly is a very interesting technology.
I think the most amazing part about this is the video at the bottom of the article: Miikshi: Cosmic Rays (4K). The caption calls it a “charming fictional animated video to explain their muon-based systems”. But I cannot emphasize enough how much this undersells it.
It’s like a weird charming mashup between Thunderbirds, Muppets and a real muon science team. You really have to just watch it.
If you had trouble understanding what the muon positioning system from the article might be used for or how it works there is a short explanation from Professor Tanaka at the end of the video.