What time is it anyway? While Egypt’s parliament deliberated over the summer whether to have daylight savings, time scientists across the world are locked in a struggle of whether to have a leap second. Yes, leap seconds are actually a thing. Measuring time during the day has always been based on the earth’s position relative to the sun on its daily axis around itself. Apparently that axis rotation has been slowing down as the tides that hit the world’s beaches takes energy out of its spin, allowing down the earth. The world’s keepers of the true accuracy of time, dubbed “time masters”, use an atomic clock to measure atomic time: 9.2 billion oscillations of a microwave beam, when tuned to the frequency of a caesium atom, roughly the equivalent to the 86,400 seconds of the day. The effects of the tide on the earth’s rotation makes it several mn times less stable than the caesium atom. In order to correct the discrepancy between the two, time masters have allowed on several occasions to hold time still at 00.00.00 for one second, called a leap second. This is has happened every other year or so since 1972, according to The Economist’s 1843 magazine.

Why would should we care? These measurements govern the world’s standard time relied upon by global positioning satellites silently travelling, planes for flying, computers for talking to each other and trading in the global markets. Sometimes not everyone gets the memo, causing glitches such as on 30 June 2015, where some financial markets chose to close for a minute, while services at Amazon, Apple, Netflix and Twitter were disrupted. The danger is more acute for global finance in light of the prevalence of high frequency trading, when a second can affect time between when an order is placed and when it is executed. When beating the competition by fractions of a second becomes crucial, a disruption that small could mess up the order of trades. Time scientists fighting for eliminating the leap year argue that the shifts would cause damages of Y2K proportions. They claim that the leap year is a throwback to when the world was much less interconnected, accusing proponents of holding on to archaic Victorian notions where Britain determined the standard. This argument is helped by the UK’s time masters leading the fight to retain the leap year, who dismiss their opponents concerns as sensationalist. Expect an extra second this year at 23:59:60 on 31 December, according to New Scientist.