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How You Got That Extra Hour To Sleep

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BY NEIL JOHNSON, The Tampa Tribune

Published: November 3, 2007

TAMPA - As you enjoy a weekend that lasts 49 hours rather than 48, you can thank Congress for the extra hour - and the railroads for time zones to begin with.

We return to standard time Sunday because the Congressional Energy Policy Act of 2005 changed the start of daylight saving time to the second Sunday in March and its end to the first Sunday in November. That would be Sunday.

The federal government didn't begin telling anyone what time it really is until the late 19th century, essentially to keep trains from running into one another, according to a spokesman for the U.S. Naval Observatory in Washington, the keeper of the country's official timepieces.

Before the federal government's involvement, each town pretty much kept its own time loosely based on the sun. People set pocket watches by their town's clock tower, and a few minutes difference between cities didn't matter much.

Nor did it matter that, based on the sun, noon for New Yorkers was 11 a.m. for Chicagoans and 9 a.m. for people in San Francisco.

Then trains began linking the country.

Trains running on a limited number of tracks with engineers operating on different times led to a series of major accidents in the 1850s, and Congress got involved in setting the nation's watches by establishing time zones.

"Time zones were developed to keep trains from crashing into each other," said Geoff Chester, spokesman for the Naval Observatory.

Every 15 degrees of geographic longitude - the up-and-down lines on the globe - mean an hour's change in time.

Though most of us will have to remember to set our clocks this weekend, no one will need to scurry around at the observatory at 2 a.m. Sunday to reset the 75 atomic clocks or the 15 auxiliary atomic clocks in a facility in Colorado Springs, Colo.

These clocks are among the few that are immune to congressional decree because they track Greenwich Mean Time. They are accurate to 1 nanosecond, or 1 billionth of a second. That's the time it takes light to travel 1 foot.

This year's extension of daylight saving time technically makes the old saw about springing forward and falling back incorrect. By choosing the second Sunday of March, Congress started daylight saving time in winter.

Before this year, daylight saving time started on the first Sunday in April and ended on the last Sunday in October.

It also might prompt us to rethink what we call standard time.

"Now we spend more of the year on daylight time than on standard time," Chester said.

Reporter Neil Johnson can be reached at (813) 259-7731 or njohnson @tampatrib.com.

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