BTW, the U in #ULID is inaccurate - it’s not universal, or even Galactic, or even Stellar level unique.

A galactic level collision avoiding random number would be at least 40 bits more (for a trillion stars). 80+40+76=196 bits. Throw in a few extra bits to make a nice round 256 bit total size and you have a #GLID.

One oddity is that the universe is expanding so eventually you will be out of light speed communication range to even nearby stars. So fewer random bits needed in far future?