Speaker 1: Welcome to brain Stuff from house stuff works dot com
Speaker 1: where smart happens. Hi Am Marshall Brain with today's question,
Speaker 1: is there an easy way to understand how time zones work?
Speaker 1: In January, people have a special interest in time zones.
Speaker 1: That's because the shouting of Happy New Year happens at
Speaker 1: midnight in your local time zone. Meanwhile, other time zones
Speaker 1: either have already celebrated the new year or they're sitting
Speaker 1: around waiting to do it. So cities in New Zealand
Speaker 1: celebrate New Year's Day first, followed by cities in Japan, Australia, Russia, China,
Speaker 1: and India, followed by cities in Europe and Africa, followed
Speaker 1: by cities in North and South America, and then ending
Speaker 1: on islands out in the Pacific Ocean like Hawaii and
Speaker 1: finally Samoa. There are four separate time zones, so there
Speaker 1: are twenty four separate times when balls drop, Happy New Year,
Speaker 1: gets shouted, and people engage in flagrant public displays of
Speaker 1: affection and intoxication. So let's start at the beginning. Why
Speaker 1: do we have time zones? Keep in mind that there's
Speaker 1: another way we could do this. We could have a
Speaker 1: single time that holds true all over the planet. When
Speaker 1: it's noon in Moscow, it could also be noon in London,
Speaker 1: New York, and Los Angeles. The problem is that people
Speaker 1: really don't like that. People much prefer for it to
Speaker 1: be noon when the sun reaches its peak in the sky.
Speaker 1: In order for it to be noon when the sun
Speaker 1: reaches its peak, everybody needs to set their time according
Speaker 1: to the sun. And this is how things used to be.
Speaker 1: It used to be that there were no clocks. People
Speaker 1: use things like sun dials. Then there were clocks, but
Speaker 1: only the rich people could afford them because they were
Speaker 1: really expensive. So a town would have a central clock
Speaker 1: tower with bells loud enough to be heard all over town,
Speaker 1: and the clock keeper would set the clock according to
Speaker 1: the sun. This system worked well until trains started to
Speaker 1: move quickly from town to town. In order to run
Speaker 1: a punctual train schedule, all the towns needed to have
Speaker 1: a coordinated time system rather than setting their clocks loosely
Speaker 1: according to the sun zenith. So the idea of time
Speaker 1: zones was created to help keep people from missing their trains. Today,
Speaker 1: the world has twenty four time zones, with all the
Speaker 1: clocks in the same time zone displaying the same time,
Speaker 1: but it can still be confusing, especially if you're trying
Speaker 1: to schedule a phone call with someone in China or Australia.
Speaker 1: How do you make sense of this? The easiest way
Speaker 1: is to get out a globe and a table lamp.
Speaker 1: The table lamp represents the sun position your globe, so
Speaker 1: that England is pointing toward the sun. In this model,
Speaker 1: it's now high noon in England. For historical reasons, the
Speaker 1: zero degree longitude line runs through Greenwich, England. This is
Speaker 1: called the prime meridian, and this place on the globe
Speaker 1: is also known as GMT plus zero or a Greenwich
Speaker 1: meantime or UTC plus zero, where UTC stands for coordinated
Speaker 1: Universal Time. So look at your globe looking down at
Speaker 1: the north pole. Imagine the globe divided into twenty four
Speaker 1: pie shaped slices. Each slice is a time zone. It's
Speaker 1: high noon in the England time zone. From the vantage
Speaker 1: point of the North Pole. The Earth spins counterclockwise. That's
Speaker 1: why the sun rises in the east and sets in
Speaker 1: the west. In the slice immediately adjacent to England on
Speaker 1: the left, it's one PM or UTC plus one. In
Speaker 1: the slice immediately adjacent to England on the right, it's
Speaker 1: eleven am or UTC minus one. As the Earth rotates counterclockwise.
Speaker 1: In one hour, it will become high noon in the
Speaker 1: slice immediately adjacent to England on the right. Five hours
Speaker 1: after its high noon in England, the Earth will have
Speaker 1: rotated enough for it to be high noon on the
Speaker 1: East coast of the United States. This is referred to
Speaker 1: as U t C minus five. The central time zone
Speaker 1: of the U S is ut C minus six, Mountain
Speaker 1: and Pacific are U t C minus seven and UTC
Speaker 1: minus eight, respectively. Hawaii is U t C minus ten,
Speaker 1: and finally Samoa is U t C minus eleven. The
Speaker 1: International date Line is on the opposite side of the
Speaker 1: globe from England, over near New Zealand. This first time
Speaker 1: zone is ut C plus twelve. This is the first
Speaker 1: time zone to see January one. Each new day starts
Speaker 1: in the time zone adjacent to the International date Line
Speaker 1: twelve hours before it's midnight in England, it's midnight in Auckland,
Speaker 1: New Zealand, eleven hours after it's midnight in England, and
Speaker 1: it's midnight in Samoa. Then the Earth rotates past the
Speaker 1: International dateline. It becomes January second in New England, and
Speaker 1: the cycle repeats. When you imagine how the globe rotates
Speaker 1: with respect to the Sun like this, it's easy to
Speaker 1: keep track of the time zones. Be sure to check
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