Leap seconds cause chaos for computers — so Meta wants to get rid of them

Photo by Gabe Ginsberg/Getty Images

There have been 27 leap seconds since 1972 to account for changes in the Earth's rate of rotation. As the Earth's rate of spin is somewhat irregular, it means solar time and universal time tend to drift apart. Leap seconds are added to compensate. This makes computers confused.

Imagine you're a computer. You have a good idea of time. You are aware that there are 24 hours in a day, 60 minutes in an hour, and 60 seconds in a minute. As you wait for the coming dawn, you watch with horror as your internal clock goes from 23:59:59 to the previously-undreamt-of time of 23:59:60). You freak out quite a bit. It's possible that you crash to calm your nerves. Some of the largest websites in the world are taken down. You get mad at everyone.

This is a real situation. When a leap second was added in 2012 it caused a lot of websites to go offline. Engineers had mostly learned their lessons by 2015, but there were still some problems. Ditto last year. It's almost every time we have a leap second that we find something. It's really annoying because it's a classic case of code that isn't run and isn't tested under normal conditions.

Meta wants to eliminate the leap second. The company's engineering team outlined their argument against adding leap seconds in a post published yesterday. Meta says that the benefit is less important than it used to be.

The company says that introducing new leap seconds is a risky practice that does more harm than good.

This campaign has attracted support from other tech giants like Microsoft, and the US National Institute of Standards and Technology, as well as heavy-hitters in the international measurement community.

What happens when there is no leap seconds? It might fall out of sync with solar time. Meta says there are options. The leap second can be achieved by slowing down digital clocks over a longer period to account for the extra time to be added.

There are issues with this method as well. The period you use to distribute the extra time is one of the ways you can calculate the time. There isn't a single method of tracking time across the world's many digital systems.

The problem of the leap second is not being suggested by Meta. There needs to be one. This is a problem that other organizations are looking at. A report on the matter will be commissioned by the UN in 2015. It is due out in the year 2023. You can't rush it.