Calculate interstellar travel time for a solar sail
Simplifed python version of the C code used for "`Oumuamua as a light sail: Evidence against artificial origin" (https://ui.adsabs.harvard.edu/abs/2021A%26A...649L..17C/abstract).
This shows that the decrease in acceleration with distance from the power source (the Sun) results in an effective terminal velocity, which is much lower than those usually suggested for conceptual solar sails.
This means that even for a huge, ultra-light, efficient sail with a modest payload, interstellar travel would take millennia, rather than decades.