It's unlikely you remember this, kudos to you if you do! On the 30th June 2012 a strange set of events happened around the world. From a total collapse of aeroplane reservation systems to server issues at major tech companies like LinkedIn, Yelp, Reddit and Mozilla. There was trouble all around the web and whilst these were some of the more noticeable impacts, most of the problems will have gone largely unreported. It was a dark day for server administrators everywhere.
Such is the severity of the event that will take place again on the 30th June 2015 that no space launches will happen that day. The high value nature of the equipment mean it's simply not worth the risk. Whilst we've learnt from the events of 2012 and there should be no repeats, it's almost guaranteed that something, somewhere will be affected. It just always seems to be the case, be it a gaming network, a ticketing system or some science experiment etc. Something will break.
What is this horrifying calamity that encroaches upon us? It's the announcement by the Earth Orientation Center of the International Earth Rotation Service that on June 30th at 23:59:59 instead of it becoming July 1st 00:00:00, it will instead become June 30th 23:59:60 first.
It's necessary at this point to delve into a tiny bit of science, simply put the Earth is ever so slowly, slowing down. As such in order to get things into alignment between our clocks and the rest of the celestial heavens, sometimes we need to add in an extra second to our time keeping. Sort of like when you add a beer mat under a table in order to stop it wobbling. We're padding time so that it's all straight and in alignment.
What happens though to your email if you happen to send it at 23:59:60 in a second that most likely some systems won't recognise? How do websites that count from 0 to 59, deal with something that's 60? Truth is there's no uniform answer, you won't notice it but Google will at some point in the future begin stretching time. What!? Not in a weird dangerous science way. They'll start setting their servers to make a second fractionally longer. So small that not a soul will notice it, but come July 1st it will hit 00:00:00 at the same time as those that apply the leap second. In it's self that's an incredible feat of engineering working on a tinier scale than we can probably fathom. The effect though is it'll be in alignment by the end and users will not be impacted. It highlights how big this problem can be. It's easier to temporarily redefine the length of a second than it is to add an extra one in.
As for little companies like us, our server software is designed to handle the gap second. In theory we should need to do nothing as the server sorts it's self out. Strange things could happen though if a blog post or shop product is added on the exact extra second. Most likely around the world some data will become lost, trapped in databases as whilst it may get logged, search protocols just won't be looking for something ending in 60 seconds.
That says a lot about the fragility of technology, we create things based on certain assumptions and as a coder in truth I would never write complex code for a site to handle one potential second every three years where odds are nothing will happen. Still because of that expect to see something in the news on July 1st because the fearsome beast that is the gap second is likely to claim at least a few victims.