Time was based on how many time zones separated a location from the Royal Greenwich Observatory in the UK. Greenwich Mean Time was determined by the average time of day when the sun passed over the Prime Meridian at Greenwich.

On Nov. 18, 1883, railroads in North America converted to a system of just over four time zones: eastern time, central time, mountain time, and Pacific time. Eventually, it became the standard across the U.S.

Even with fewer time zones, time confusion arose again in the 20th century. Air travel, the internet and mobile devices gave us a 24-7 culture in which we're tightly interconnected to events in other parts of the world.

Another solution was proposed: Abolishing time zones and putting the entire world on universal time (UTC). Under this system, it's 9:00 everywhere on the planet, even if it's morning in one place and evening in another.

The switch to universal time has already taken place. Pilots and air traffic controllers in the U.S. rely on universal time. So do financial traders who deal across time zones. The internet essentially runs on universal time.

The switch to universal time may cause initial disruption. People say, 'if we went universal time, that would mean we'd have to open businesses when it's dark outside.' In reality, your business would go on with the sun, as usual.