On the other hand, TAI does not take into account the variations in Earth’s rotation speed, which determines the true length of a day. For this reason, UTC is constantly compared to UT1. Before the difference between the two scales reaches 0.9 seconds, a leap second is added to UTC.
On average, Earth has been slowing down a bit over the past decades, so UTC is currently running 37 seconds behind TAI.
Why not metric time(TAI)?
Reasons.
Reasons just states difference, but does not answer why.
There’s literally a section titled ‘why use UTC - not TAI?’.
Or why not just seconds past the epoch?
leap second corrected or not?
Metric seconds or UTC seconds?
I’m gonna say SI
Is that supported in any common operating systems?