I think a more interesting argument is: Humans are 24-hour creatures (ok, maybe not precisely 24 hours, but close enough). That's how our internal clocks are wi

I think a more interesting argument is: Humans are 24-hour creatures (ok, maybe not precisely 24 hours, but close enough). That's how our internal clocks are wired. Its not nurture; its nature; and it would take generations living day-in day-out with a different cadence before we see biological adjustments. Sure, our clocks are 24-hours-a-day because that syncs up well with the rotation of the earth. That's the scientists' argument, and it isn't why we use a 24 hour clock. The real reason is because it syncs up well with our biology. Its hard to imagine a world where these two things aren't synced up, but we're headed to some soon, and its likely that any clock which doesn't sync up to our biology (TimeAwake + TimeAsleep = 1 Day = 86400 seconds) will be rejected by anyone who isn't ordered by their commanding officer to use it. Its like... just use UTC. Be done with it. The argument that "its an Earth Time, and we're Interplanetary now" feels like its coming from a sci-fi fan-fiction writer obsessed with The Expanse and solving problems before they exist. The most important priority for any timekeeping system is that its Useful. The second highest priority is that its Scientifically or Mathematically Beautiful, and this second priority is so far below the first one that we invented timezones and daylight savings time and everyone who has ever had to think critically about either of these things wants to jump off a fucking bridge but we tolerate it because they're Useful (and, we're getting rid of DST, because we've recognized that its Not So Useful, again, Usefulness drives everything). Here's what's going to happen: they'll invent some kind of new Lunar Time with 29.35 earth-day long days or some other nonsense. Every clock on the wall at Moonbase Alpha will have both Lunar Time and UTC and probably US Central Time because Houston & NASA. The scientists who invent it will pat themselves on the back. The janitors who clean the place will have their shifts scheduled in UTC hours and the Gregorian calendar ("yeah man I'm off at 8pm and I don't work again till Monday, yeah I guess it is weird that its been night outside for two weeks yet we still say 'monDAY', I don't know man I just work here same as you let's grab some drinks"). In 350 years, the Martian Humans will declare independence and reject all forms of Timekeeping that Us Earthlings invented, including the one the ESA (hint: EUROPEAN space agency) tried to invent for them, because Politics. Can we just, I don't know, focus on GETTING to the moon first, before we start paying people to retrofit our microwaves with new clocks?