It was on this date in 1972 that the first leap second was added to a day.
The modern definition of a “second” was settled in 1874 by European scientists working from Muslim scholars’ improvement on Ptolemy’s Second Century calculations. But in the early 1960s astronomers realized that the rotation of the earth is irregular -- fundamentally, it is slowing.
Coordinated Universal Time (CUT), calculated with an atomic clock, was systematically slowed each year, for a decade, to compensate. But that meant that CUT and UTC (the time standard used by broadcasters, transportation providers, and other commercial and military users, a standard still fixed on the original definition of the “second”) were diverging. To true them up, the leap second was added to the UTC.
Since 1972, a total of 25 seconds have been added -- that’s to say, the Earth has slowed down 25 seconds compared to atomic time since then.
But this does not mean that days are 25 seconds longer nowadays: only the days on which the leap seconds are inserted have 86,401 instead of the usual 86,400 seconds.
Salvador Dalí and Walt Disney were friends. They met at a party in 1944 and soon began collaborating on a surreal animated short together. Destino didn’t get finished in their lifetimes but was ordered to completion in 1999 by Walt’s nephew Roy, who discovered it in the vaults. This hour-and-twenty-minute documentary tells its story. Now, […]
In barely months, a 16 year-old Swedish activist has changed the record on climate change, drawing the attention of the world to a problem as it becomes critical–and the contemptuous wrath of politicians and pundits who think she’ll go away if they just call her a stupid little brat again. Greta Thunberg is Time’s Person […]
Omni Calculator asks a few questions about your internet usage and tells you what else you might consider doing instead. And yet, for some reason, I find myself wary of completing an online questionnaire about my online habits. Thankfully it’s a simple calculation, writes Emma Charlton: Cutting out three 10-minute social media checks a day […]
You’d be surprised anyone would have to say this, but…there are plenty of items that don’t belong in a suitcase. Like a bag of dead birds. No, really…people are actually packing bags of small dead birds into their luggage these days. Look, we can’t tell you how to pack. That’s your business. But we can […]
Presidents’ Day and VPNs may not be a natural fit at first glance. But think about it for a minute. George Washington and Abraham Lincoln were both American presidents whose legacies are forever tied with liberty and freedom. And what is a VPN service if not absolute web liberty and freedom for all your digital […]
You hear the stories all the time. You know the ones about how a new vehicle instantly loses hundreds, even thousands of dollars in value the second a new owner drives it off the lot. Depreciation is a killer, especially when the item itself works just as well — or maybe even better than all […]