Got a second? You'll actually have an extra one Tuesday.
Every so often, the official time keepers of the world add an extra second to the clock to keep time on track. But computer systems are a risk of glitching with the time flux.
So, what is a "leap second," and how does it work?
It's a tiny time alteration, but it's significant. Just one 61-second minute may be enough to crash complex computing systems.
The leap second was unleashed in the 1970s as a way to make up for slight variations in time. The Earth doesn't rotate at exactly the same rate every year, so this small adjustment allegedly keeps us all on track.
This year's leap second happens at 8 p.m. EDT Tuesday, June 30, 2015 — that's midnight in London and according to UTC, the world's time standard.
But it also coincides with the opening of many Asian financial markets, so extra-second-worries have set in.
The Nasdaq is shutting down at 7:48 p.m. EDT. Other major exchanges are also trading early or opening late.
There is reason for concern. In 2012, a leap second crashed multiple websites, including Yelp, Reddit and Foursquare. Qantas Airways, in Australia, lost its entire system for hours and had to check in passengers by hand.
Google has a fix in place. The company said it will add milliseconds to its servers all day instead of one whopping second all at once.