Talk about a famous clock:

The countdown clock at @NASAKennedy was once considered one of the most-watched timepieces in the world. It sits a few miles west of historic pad 39A, which was home to numerous launches throughout NASA’s space program…including Apollo 11.

We’ve all heard the countdowns to “T minus zero,” which is when we all expect the rocket to liftoff and soar into the atmosphere. But T-0 isn’t necessarily the time that the engines ignite.

For example: the Apollo Saturn V launch sequence listed engine ignition at T-8.9 seconds. The Shuttle main engines started at T-6.6 seconds, launch thrust at T-3 seconds and booster ignition at T-0.

“T minus zero” is actually referred to as “an action or event that results in a substantial change in the amount of control you have over a situation.” In other words, countdowns are counting down to a change…and not necessarily a launch.

And there’s your new-decade-metaphor for the day. (Image: Sandy Marshall)