Hacker News

In a society that throws out the hours and minutes, why did they keep our second?

When migrating from Earth to a new planet, they kept the seconds because a lot of our science is built around them. They did the same with the meter, kilogram, and Kelvin degree.

And, when their descendants were colonising back Earth, they lost access to most scientific apparatus that was transported with them, due to software failure. The cryogenic chambers were supposed to open as soon as they detected liveable conditions; instead they opened millions of years later, as the radioactive material fuelling them run out.

It's somewhat easy to guesstimate a second, so they guesstimated the Earthling day into 80ks, just temporarily, for their own convenience, until they got access to better tech. It was close enough, unlike 100ks.

...except that nothing is more permanent than a temporary measure. They died without measuring the day properly, their children weren't able to do so either, and eventually all that story about "we came from the stars" became folklore.