Lol. Just happened to log in this morning and this notification was waiting on me.
Old habits are hard to break I guess!
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I’m glad you check in every day. I try to but miss lots of days because of other things that get in my way.
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That’s what’s most surprising to me. I do know I’m one of those types that has to check anytime a number pops up on any app indicating there is a notification. My email inboxes have no unread emails. Everything gets junked or filed away as soon as i take action, if necessary. I think it’s just undiagnosed OCD.
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At least you’ve finally got an official diagnosis.
Oh, EDIT: Nah, a year is 365.2425 solar days (86400 nominal seconds; TAI seconds may vary). Sorry.
OCD, whatever.
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@ClaudnDaye Could you at least spell it alphabetically. CDO - CDO! 
@jbowler Does that include the notorious leap-second? 
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The solar second does not match the atomic clock second - the TAI second. Since most computer systems run on TAI seconds they get out of step with the solar day and an extra TAI second is added or removed. The solar second remains as 1/86400 of a solar day.
So when we convert from seconds to days we just divide by 86400 - the leap seconds are irrelevant. When we want to convert to atomic clock time, which is currently 37s ahead of solar time (UTC) it gets more complicated; there’s a big table of when the leap seconds were introduced here:
That also contains the explanation I just gave. However because the leap second is only inserted or removed when the error reaches 0.9s that table can’t be used to get accuracy even to the second! This is where UT1 comes in; it meant to be the exact solar time. BIPM (the International Bureau of Weights and Measures, in French) is in charge but the NIST page above gives the UT1-UTC to ms (1/1000th of one second) accuracy, so given the whole table it’s possible to get back to TAI for a given time in the past, at least up to when the leap seconds were introduced on January 1, 1972; prior to that the “rubber second” had been used.
The earth wobbles so the time of the next leap second cannot be predicted more than a few months into the future. We get around 6 months notice of the next one, which sounds like a lot but the last one at the end December 31, 2016 caused major breakage, in particular to Cloudflare:
Leap seconds have broken all sorts of stuff. It is said that Russia’s GLONASS “GPS” satellite system is going to have problems if one is introduced…
Fortunately the earth has been speeding up, so solar days are slightly shorter in terms of TAI seconds; not long enough for the solar day to reduce the 37s discrepancy for more than 10 years but enough that it was estimated that the next leap second would not be required until somewhere around 2038.
All the same various people with expensive equipment that they don’t want to spend money on are so scared that there has been a push to junk the leap second in favour of something longer; like a day, a month, the lifetime of the universe.
Well, in fact, 10 days ago the decision was finally made to go to leap hours:
(timeanddate.com is where I learnt pretty much everything I’ve written here.)
Those who know the history of the Julian calendar will recognise this; when Julius Cæsar eventually had the Roman calendar fixed everyone knew that the fixed calendar was going to drift, but not for, maybe, a thousand years. Julius Cæsar anticipated:
Nulla alia actio necessaria erit donec differentia inter UTC et UT1 unam horam attingat, quo momento orbis terrarum constituendum erit quid deinceps agendum sit.
Well, I don’t know what he really said; it probably involved several forceful Latin words, so I just took the above statement from the timeanddate.com web page above and translated it into Latin.
The Julian calendar was not fixed until 1582, many hundreds of years after it was way out of whack (slightly over 10 days in 1582) and, to this day, some Abrahamic religious groups use the old calendar.
How’s that for TL;DR?
EDITTED: To correct the recent changes to the earth’s rotation speed; it is speeding up, not slowing down, which is why rate of introduction of leap seconds has slowed (the original explanation made no sense 
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@jbowler I GIVE! I GIVE! TMI OR TL:DR! 
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