What can happen in a second?
Apparently a lot.
The world is cautiously preparing for something taking place Tuesday called a "leap second."
Even though it'll happen in the blink of an eye, there are fears the added heartbeat could throw off major computer systems.
Experts say leap second is a lot like leap year, only a whole lot shorter.
So, why do we do it?
It turns out the earth isn't spinning as fast as it used to.
"It's just a small correction between the rotation of the earth which is changing and the atomic clocks which are nearly perfect," Professor Dan Snowden-ifft of Occidential College in Los Angeles, California said.
But what isn't nearly perfect is how computers deal with the added second.
Last leap second in 2012, internet companies like Reddit, Yelp, and LinkedIn got knocked offline.
Even Australian airline Quantas saw their computers go down.
But Professor Snowden-ifft says no one should leap to any bad conclusions.
"I don't see anything catastrophic happening here," Snowden-ifft said.
So just think of all that extra time you'll have Tuesday!
Plenty of new plans being made based on that bonus second.
The extra second will be added as the clock strikes midnight universal time, meaning the extra second will come for people in the United States at 8 p.m. EDT.