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Why do they have time zones?
Many persons prefer to do certain things during certain parts of the day, such as sleeping at night and rising in the morning. Getting a telephone call can be worse during certain parts of the day. Since the Sun is always rising somewhere, and is always setting somewhere, it is never night all over the world.
Also, for religious reasons, many persons all over the world do certain things on certain days, and they need a definition of when each day begins.
Before there were time zones, folks relied on local solar time. However, when they traveled, it became necessary to observe the time wherever they went. Also, with the invention of the telegraph, it was a lot of work to convert the different times from different towns. Many railroad companies used different times, which confused travelers, especially at transfer points, which are stations served by more than one line.
Using time zones of one hour made the arithmetic a lot easier.
Is it ever the same time in Chicago and New York?
Yes. It is always the same time in Chicago and New York. When it is 12:00:00 noon, Central Standard Time in Chicago, it is 12:00:00 noon, Central Standard Time in New York. When it is 13:00:00 Eastern Standard Time in New York, it is 13:00:00 Eastern Standard Time in Chicago. A time of day, without the underlying denomination, is meaningless. Its like omitting the units of measure on your science project report. Often, the underlying denomination is not mentioned because it is understood.
When daylight saving time ends, there is one hour when folks in Chicago are still observing Central Daylight Saving Time and folks in New York are observing Eastern Standard Time, and the two are equal.
Instead of asking what time it is in Chicago, a better question is, What is the local time in Chicago?
What is daylight saving time?
Daylight saving time, which is singular, amounts to pretending it is an hour later than it really is. Remembering it this way makes it easier to figure out whether you would be an hour early, or an hour late, if you failed to change your clock.
Lets say you are supposed to be in school at 7:40 and you fail to change your clock. In March, when the school changes their clock and they begin observing daylight saving time, if you arrive at 7:40, they will be pretending it is 8:40 and will consider you to be late.
In November, if you arrive at 7:40 daylight saving time, they wont be pretending it is 7:40, after changing their clocks back one hour. To them, it is 6:40 and the doors might still be locked.
Daylight saving time does not make the Sun set later. It simply assigns a higher number to the time when the Sun sets.
Why are time zone boundaries so irregular and jagged?
You may wonder why the meridians running from the North Geographic Pole to the South Geographic Pole are so straight while the boundaries of time zones are so jagged.
If they followed 112.5° west of Greenwich
Part of the former Greeley Elementary School in Butte, Montana would have been on Pacific Standard Time and part would have been on Mountain Standard Time. Now, the school is closed. This meridian runs through some very sparsely populated land, and doesnt find much interesting.
If they followed 97.5° west of Greenwich
Considering that Mountain Standard Time is the mean solar time at the meridian 105° west of Greenwich, and Central Standard Time is the mean solar time at the meridian 90° west of Greenwich, why not simply draw the boundary halfway between them?
Well, lets see what would happen. Halfway between them would be 97.5° west.
Most of this church in Crofton, Nebraska would be on Mountain Standard Time, while one wall would be on Central Standard Time.
The boundary would run through the heart of Oklahoma City, and within two blocks of the State Capitol Building. Folks would constantly have to specifiy whether the time of day is Mountain Standard Time or Central Standard Time.
The boundary would run through the Oklahoma History Center. The images are from Google Maps.
When should the tardy bell ring at Zaneis Elementary School in Wilson, Oklahoma, if part of the buiding is on Mountain Standard Time and part on Central Standard Time?
Check-out time would be based on Mountain Standard Time in some rooms and Central Standard Time in others.
Coreslab Structures in Oklahoma City would be split, throwing work and delivery schedules into a mess.
Part of the Target store in Moore, Oklahoma would be on Mountain Standard Time, and part would be on Central Standard Time.
Part of Cedar Creek Elementary School in Cedar Creek, Texas would be on Mountain Standard Time and part would be on Central Standard Time.
Part of Welder Elementary School in Sinton, Texas would be on Mountain Standard Time and part would be on Central Standard Time.
Most of the municipal courthouse in Brownsville, Texas would belong on Mountain Standard Time, but a corner would belong on Central Standard Time, along with the county offices across E. Levee Street.
The boundary would cut through Greyhound Plaza in Brownsville, Texas. No, its not a bus station. We dont get to have that much fun.
If they followed 82.5° west of Greenwich
The boundary between Central Standard Time and Eastern Standard Time would run through Tampa, Florida.
The boundary would run through Jesuit High School in Tampa, with the football field on Eastern Standard Time and the baseball field split.
The boundary would run through this office building.
Part of this county jail in Mansfield, Ohio would be on Central Standard Time, and part would be on Eastern Standard Time.
Part of Tolsia High School in Fort Gay, West Virginia would be on Central Standard Time and part would be on Eastern Standard Time. How could your class schedule make sense? Every time WFGH-FM 90.7 announced the time, they would have to clarify which time denomination.
Part of the Church of God in Belton, South Carolina would be on Central Standard Time and part would be on Eastern Standard Time.
Imagine the race car drivers having to change their watches every time they crossed the time zone boundary.
Some religious denominations start their holy days at midnight, and hold forth a celebration of some holy days, beginning at midnight. If their house of worship is split by a time zone boundary, when is midnight?
It is worth noting that many of the problems with straight time zone boundaries would not arise in a free country, with liberty and justice for all.
In a town split by a time zone boundary, curfew would be an hour later in the western part, but in a free country, there would be no curfew. Anne Franks diary, 20 June 1942, laments that a curfew was imposed on Jews.
Liquor stores and bars would have to close an hour earlier in the eastern part of the town, but in a free country, the owner of the building would decide whether to operate a saloon, and when to open and close. There would be no restrictions on what hours a business could be open or sell merchandise. Thats because opening a saloon and keeping it open does not violate anybodys rights. You dont have to go in there.
It is illegal for telemarketers to phone you before 8:00 or after 21:00 your time, but in a free country, with liberty and justice for all, night shift workers would enjoy the same protections during their daytime sleep hours as day shift workers enjoy during their nighttime sleep hours.
Turning on headlights 30 minutes after sunset would be the same, regardless of what number is assigned to sunset.
Even without some of the problems, the Sixth Amendment to the U.S. Constitution still affords a defendant in a federal criminal case a compulsory process of obtaining witnesses in his favor, and if you are that witness, the legal process you are served, called a subpoena, would still have to say when you must appear in federal court to testify.
The boundary between Eastern Standard Time and Atlantic Standard Time belongs at 67.5° west, and conveniently, there is an international border handy nearby, so the time zone boundary follows the border. This is an example of a reasonable adjustment.
The meridian where boundary between Central Standard Time and Eastern Standard Time belongs, at 82.5° west of Greenwich, and is marked by the red line at the right. The black line shows the actual time zone boundary, way west of where it belongs. That is an example of a very unreasonable adjustment.
Only the sliver of Michigan between the red line and the Canadian boundary belongs on Eastern Standard Time. Putting all of Michigan on Central Standard Time would be reasonable.