• Day 29: It's All The Same Problem

  We’re twenty-nine days into this. I’ve thrown twenty-eight different time problems at you. Sundials, cesium fountains, leap seconds, Unix epochs, DST, lunar time, the Y2038 bug, calendar drift, time zones in Nepal. Twenty-eight posts. …

• Day 28: What an Interplanetary Civilization Needs From a Clock

  A couple of weeks ago, on Day 12, I took the tour. A Mars day is 39 minutes too long. The Moon’s clocks run about 58 microseconds a day fast. A round trip to Voyager takes two days. Astronomers already juggle a whole family of relativistic …

• Day 27: People Have Tried This Before

  Yesterday I dug into the astronomical anchor problem: whether civil time should stay tied to the sun, and the complications that come with loosening that tie. Redesigning civil time at scale is extremely complex, and I don’t pretend to have …

• Day 26: The Astronomical Anchor Problem

  If Einstein’s gift to us yesterday was that there is no universal “now,” today I want to come back down to Earth and revisit something more practical: how we measure time, and how we define the second. We dug into the second itself back on …

• Day 25: There Is No Now

  Week 5 starts today. For four weeks we’ve been poking at how humans organize time: clocks, calendars, time zones, leap seconds, DST, software bugs, political fights. All of it rests on a quiet assumption. There’s an objective fact about …

• Day 24: Three Calendars Nobody Uses

  Yesterday we covered the Gregorian calendar. Today we’re going to talk about the attempts to replace it. There was one that almost passed at the United Nations in 1955, and one that Kodak quietly ran for sixty-one years. And there’s a …

• Day 23: All the Calendars Are Just Made Up

  You probably haven’t thought about this much before, but the calendar on your wall is, as a piece of civic infrastructure, bizarre. It’s the result of two and a half millennia of duct tape and wood glue. The current global standard, the …

• Day 22: "Permanent Standard Time vs Permanent DST"

  Yesterday’s post we saw most people want DST abolished, that the data is one-sided, and yet we’re still doing it. The reason, the whole reason, is the question I want to spend today on. If you abolish the biannual switch, which time do you …

• Day 21: "DST is Dumb"

  Most people think daylight saving time has something to do with farmers. It doesn’t. It never did. The farmers, in fact, hated it. DST shifts the workday by an hour, but it doesn’t shift the cows or the dew, and farmers fought against it …

• Day 20: The Leap Second Is No More, Huzzah!

  I know yesterday’s post was a real cliffhanger. Talking about leap seconds. I hate to burst your bubble, but today there’s going to be more of that when we cover the exciting and well-documented, internationally renowned meeting in November …