4 ms·

Don't forget it starts out with "universal". It's not just bound to Earth. We have greater aims than that ;-)

• tialaramex 7y ago
  It really is bound to Earth. It's defined based on TAI (which needs a bunch of atomic clocks all sat on Earth's surface or adjusted to allow for altitude) and the International Earth Rotation Service (which measures how quickly the Earth spins) so as to have it track TAI over the short term, but occasionally inject "leap seconds" so as to track the spin of the planet and keep the relationship between apparent sun position and UTC as expected. Time isn't really universal by its nature, but at human scale and in a relatively small place like Earth you can mostly pretend it doesn't matter, and UTC helps do that.
  • mfer 7y ago
    Next time I'll have to remember my sarcasm closing tag.