Difficulty adjusted proof of work chain is the discovery -- it comes to exist on most advanced planetary civilizations. Bitcoin is the particular implementation for Earth that Satoshi invented.

Perhaps a hexadecimal first planet has 16 minute block time... then again, what's a "minute" over there in the first place?

Here's a neat idea: space travel might get driven by people who want to validate their pet (minor) adjustments to Bitcoin. 😂 We will get covenants well before that so idk what people will want beyond that.