The UTC is completely 100% arbitrary. The only reason it’s there is because an observatory happened to be on a specific hill, and then it drifted a bit (like most human things do), but the UTC/GMT has since it’s conception been completely arbitrary measurement. There isn’t a way to define a 0 latitude on a rotating sphere without making it an arbitrary point.
The UTC is completely 100% arbitrary. The only reason it’s there is because an observatory happened to be on a specific hill, and then it drifted a bit (like most human things do), but the UTC/GMT has since it’s conception been completely arbitrary measurement. There isn’t a way to define a 0 latitude on a rotating sphere without making it an arbitrary point.