Blink and you miss it! 
Planet Earth has recorded its shortest day since records began.
The 1.59 milliseconds shaved off the usual 24-hour spin on June 29 raises the prospect of a leap second having to occur to keep clocks aligned. This would be the first time global clocks have been sped up.
The Earthâs rotation has been known to slow down, with 27 leap seconds needed to keep atomic time accurate since the 1970s. The last was on New Yearâs Eve 2016, when clocks paused for a second to allow the Earth to catch up.