Earth has recorded it's shortest day on record, with concerns a 'leap second' could be needed to keep clocks correct.
Last month almost 1.6 milliseconds was shaved off one particular day, raising questions about a 'negative' moment to re-align time.
Timekeepers have been forced to add 27 'leap seconds' since the 1970s - essentially creating a minute with 61 seconds to keep clocks correct.
Astronomical Institute researchers say 1.6 milliseconds might not be noticeable in isolation, but it can add up and throw clocks off the sunrise-sunset schedule.
