Next weekend on Sunday November 6th, those of us in states that recognize Daylight Savings Time will turn our clocks back one hour at 2am. Why in the world do we do this? Why do some states not do it? What are time zones all about? Can we ever travel back in time and kill our own grandfathers so we couldn’t exist to do it in the first place? And what’s up with that arbitrary line we drew around the planet so that when you fly from the US to Australia you lose a day of your life?
Every second grader knows that it’s not the same time in New York as it is in San Francisco, but why do we have time zones and what exactly are they? Time zones are man’s way to artificially make it roughly the same time on a clock in each place across the world when the sun is at the highest point it will be in the sky each day. This is important as it facilitates business and commerce. Otherwise, if we all followed one time, some of us would be trying to find a bar to get an after work beer at 5pm but it would be the middle of the night.
First proposed in 1879 by Sir Sandford Fleming of Canada, each time zone corresponds to roughly 15 degrees of longitude. Theoretically, this is a nice, even way to divide the globe up into zones called “lunes” because they are wedge shaped like the crescent moon. The idea is that each time zone is one hour earlier than the one to its West. Man gets in the way though, because on land, political boundaries cross these nice even lines. In the United States, we adjusted the time zone boundaries to follow our political boundaries so its at least the same time in each state (except for Idaho, Oregon, the Dakotas, Nebraska and Kansas).
Two of the largest countries in the world (largest in terms of longitude) are China and Russia. They have a lot of things in common, but they take more or less opposite approaches to time zones. Russia has 9 time zones, and China does not have any at all. You read that right – the entire country uses the same time. For a country spanning 60 degrees of longitude, it should have 4 time zones, but it has one. As you might imagine that makes it pretty difficult for people in far western China to do business across their own country. The only saving grace is that most of the people in china are in the Eastern part of the land.
Israelis and Palestinians clocks show the same time most of the year, but Palestinians in the West Bank and Gaza observe Daylight Savings Time (DST) at differing dates in the year as a means of showing independence from the Israelis. In addition to lobbying for their own postage stamps, Palestinians they have even recently been adjusting for DST in coincidence with the Islamic holy month of Ramadan. So you have two groups of people who don’t care much for one another living with a few miles of each other now arguing about what time it is.
If you’re curious about time zones and all the weirdness imbued upon them by politics, you can learn more via the interactive globe over on the BBC’s website:
What exactly is Daylight Savings Time? Daylight Savings time is a lot more controversial than you might think (Ok, well…not really). The concept of artificially adjusting the time backwards one hour in the fall, and forwards one hour in the spring was first proposed by the New Zealander George Vernon Hudson in 1895, and independently a few years later by William Willet in London in 1905. Willet was disappointed at the amount of daylight time left after work in the summer to play golf.
Since DST makes more sense the farther north you go, some southern countries and states don’t bother. Arizona doesn’t follow it, neither does Hawai`i. Kazakhstan abolished it in 2005. The practice has marginal but real benefits to public health and safety, transportation safety, and leisure sports. Here in Tahoe backcountry skiers are stoked on DST in the spring, because we get one extra hour of daylight to go skinning after work. But arguments still rage in countries around the globe about whether to follow it or to get rid of it.
The biggest time zone boundary of them all is the international date line. I can’t remember how many times I flew back and forth between New Zealand and the US when I was in grad school. Since I live here now and didn’t stay there (more like they wouldn’t let me stay because I didn’t like the All Blacks enough), what about the last time I crossed the line and gained a day? HEY! Check me out! My life is one extra day longer – I’m so much better than you at life!
The date line follows the longitude line of 180 degrees, opposite of the prime meridian that runs through Greenwich, England. The concept of adding a day when crossing 180 east and losing a day when crossing 180 to the west was first proposed at the International Meridian Conference in 1884, when the world was divided into 24 hour time zones I talked about above.
Luckily for most of us, the date line crosses mostly empty tracts of the Pacific Ocean and only affects those of us jetting around the globe in airplanes from one hemisphere to another. If you look closely though, there are a lot of small island nations that lie in and around the path of the International Date Line. As a result, in the same was that US States adjust the time zones to match their boundaries, Pacific Island nations do the same – check out how much the line zig-zags around their borders.
Poor Samoa – they really get the short end of the stick when it comes to time since they deal mostly with Australia and New Zealand and they’re one day behind. But they aren’t going quietly into the night, they’re stepping up and dealing with it directly – by losing a day and being done with being on the east side of the date line and redrawing it. On Thursday December 29th, Samoans will lose a day and jump straight to the 31st. Anyone unlucky enough to have a birthday on the 30th will have to wait to hear “Manuia Le Aso Fanau” the day before or the day after.
What if all of this time manipulation didn’t matter at all and you could bounce around in time to whenever you want? Humans have always wanted to travel through time, whether it be to go backwards to experience days long gone or to move into the future to know what it holds for us. Could you go back in time if you flew backwards around the earth like Clark Kent? Well, the answer is – probably not in reality.
Only a few weeks ago, scientists at the CERN particle accelerator in Europe reported that they had managed to break the speed of light by beaming subatomic particles through 730 km (~450 mile) of rock, water, and air from their lab in Switzerland to Gran Sasso in Italy. Their incredibly sensitive detectors recorded the transmission of the particles 60 nanoseconds, or 60 billionths of a second, shorter time than the 2.4 thousands of a second light would take to travel the same distance. This flies in the face of 106 years of the Albert Einstein’s theories of special and general relativity explaining the existence of the universe and the laws of physics that govern it, all underpinned by one unbreakable law – the speed of light. Nothing can travel faster than light. So if humans just broke this speed limit, does this mean that time travel is here?
Not really, but the recent discovery is very promising. Many serious-minded scientists have theorized about time travel, including the late Carl Sagan. He postulated that time travel forwards in time might one day be possible once humans advance technology and energy to the point where we can accelerate things close to or beyond the speed of light. Pretty much just like the researchers at CERN just did.
Einstein’s theory of general relativity quantifies the relationship between energy, matter, and the speed of light (partially via his famous equation: E=MC2; energy is equal to mass times the speed of light, squared). One of its central tenets is that the concept of time is not absolute and linear – it can change relative to velocity. A clock in a speeding car is a few hundred billionths of a second faster than a clock sitting still. This effect becomes amplified the faster the clock travels, so if it achieved 99.999% of the speed of light, it would pass a year in the same amount of time that 223 years went by at the stationary clock (Davies, 2003). No matter how hard you mach down the Pony Express in the Palisades, you’re still not going to warp forward through space time and get to the Chamois the next day, but you can sure keep trying.
Time traveling back in time is another story all together. The grandfather paradox stands as one of the main barriers to backwards time travel. Imagine yourself traveling back in time, and accidentally running over your own grandfather with a horse and carriage. If he was killed before he had the chance to create your father, who never existed to meet your mother and have you, then how could you ever exist to be able to one day travel back in time to kill him?
If time traveling into the past ever becomes possible, wouldn’t we already know about it because we’d have flying cars and hover boards? It makes perfect sense that if humans ever invent the technology to travel backwards in time, the past and certainly the present would be full of these people from the future. According to the tin foil hat crowd and a lot of people in south-central Nevada, this already happened and was covered up by the government…but I don’t buy it. Carl Sagan wrote a really interesting book that got turned into a movie called Contact, starring Jodie Foster, in which a scientist utilizes wormholes to travel into the future. Believe it or not, the novel actually spawned bunch of legitimate scientific papers on the mechanics of time travel and wormholes.
Maybe one day we will have this novel to thank when we are zipping around in space time and telling our high school selves how to get lucky since we were hopelessly unable to figure it out on our own. For now though, I’m afraid if you really want to buy a time machine, as Kip and Napoleon did, you probably shouldn’t look on Ebay. Sorry, but you’re just not going to be able to go back to ‘83 and take State.
Davies, Paul 2003. How to Build a Time Machine, Penguin Books.