Sixty seconds equal a minute and 86,400 seconds equal a day, right? Technically not on June 30, 2015, when an extra second will be added to clocks as a leap second. The additional unit of time termed as leap second is meant to account for the naturally occurring slowing of the Earth that is caused by earthquakes, volcanic eruptions and other natural phenomena. While that slowing rotation is very gradual, chunks of milliseconds are added every year to gain a complete second. The leap second was identified in 1972 by International Standards and since then, there have been 25 such seconds added to the clock. That means the Earth has become 25 seconds slower in its rotation since 1972.

Does that sound scary? Wait, till you hear this. An additional second might not bother many people but it’s a big problem for computers. Computers are programmed to understand 60 seconds in a minute and once the internal processor fails to do it, then there are problems like multiple flight delays and websites like Reddit, Yelp and Foursquare going down. There’s little chance of a large-scale technological shutdown, as was predicted in the run up to Y2K, that turn-of-the-century panic when companies were worried their computers would go haywire because they recognized the year 2000’s double-zero ending as 1900.

A 2012 leap second led to 400 flights being delayed in Australia which forced the airport workers to check-in manually rather than using computers. So, is there a way we can avoid such problems? Yes, there is. The best way is to use ‘Leap smear’, a product by Google that gradually starts adding many milliseconds in your computer. The computer slowly adapts the added value since it’s been added in small numbers and remains safe from leap second effect. The next time you think that an addition of a second is nothing but a small time change, you might need to think again.