Fascinating Stuff About Time
It’s about time! Or is it?
What is time anyway? Isn’t it just something we humans invented? A second used to be defined as 1/86,400 the length of a day. As greater accuracy was needed, that method was dropped. Earth doesn’t always take exactly the same length of time to rotate once on its axis.
Tidal friction as influenced by the sun and the moon affect earth’s rotation time. As earth is closer or farther away from the sun (it varies by two million miles–3.2 million km–from us from winter to summer), the sun influences our planet differently. In fact, the influence of the sun is not just a fluctuation back and forth. The length of an earth day increases by three milliseconds each century.
Not much you say? In the time of the dinosaurs, earth would have taken 23 of what we call hours to rotate on its axis. That’s not like setting your clocks back an hour in autumn as daylight saving time ends. That’s sunup to sunup every day, 23 hours.
Even weather can change earth’s rotation slightly. When El NiÃ±o years take place, strong winds alone can slow earth’s rotation by a fraction of a millisecond each day. If that doesn’t sound like much of a change, remember that it’s nothing more than wind blowing over the surface of our large planet that slows its rotation.
Philosophers and physicists (at least some of each) debate among themselves as to whether or not time actually exists. One school of thought in philosophy says that time doesn’t exist at all, that each “moment” in our lives is like a snapshot instance that comes with memories of a past, sensations of a present and anticipation of a future. Some say we live only in once instance, ever, while others say life is like a flipbook of life instances and no one knows how fast the book flips (we just made up seconds, minutes, hours and so on to satisfy ourselves).
Some physicists speculate that time comes out of some reality even more basic. And timeless.
How sure are you about the length of a second or a minute? In A Hitchhiker’s Guide to the Galaxy, Douglas Adams claimed that “Time is an illusion. Lunchtime doubly so.” Most scientists today believe that time was created with the Big Bang, some 13.7 billion years ago. They decline to speculate on time before the Big Bang because that’s too “outside the box.”
Astronauts and Cosmonauts age differently from those of us on earth when they are in space. According to Albert Einstein, time slows the faster you travel. As you approach the speed of light, time almost stops. Because the space station people travel around earth faster than we do on the surface, time passes slower for them and they age slower as a result. Or do they age faster in space? (See below.)
As a large part of work on space and the cosmos depends on Einstein’s theory of relativity, which uses space and time as its basis, scientists really hope that time exists. At the moment, the space part of the theory seems to be considered differently. Space is no longer considered an empty void, but is filled with dark matter and something else. What is visible in space comprises only four percent of what is out there, according to recent studies.
You have likely heard that the universe is expanding at an increasingly faster rate. No one can explain that reasonably, so dark energy was devised as a theory to explain why the universe that should have been coming back together by now is spreading out faster. Does that mean that time should be slowing or speeding up for us if we are part of what is moving away from the central core of the universe at an increasingly faster rate? Science isn’t clear on that.
Three Spanish scientists claim the expanding universe is a myth. They say that time is actually slowing, thus measurements that show the universe expanding fast seem longer when it is in fact not at all. According to their mathematics (it’s all very formal, not just idle speculation), time will eventually come to a dead stop and everything will stop dead as well. (If that time comes, we had better have some good memories to count on.)
Getting back to something more understandable about time, a study recently calculated that a commuter in a U.S. city loses about 38 hours a year of his or her life waiting in traffic delays.
Have you read about people speculating as to why clocks get changed for daylight saving time each year, most claiming how foolish it is? As the story goes, the practice began as a joke by Benjamin Franklin. He said that people should wake up earlier on summer mornings so they could get more work done during daylight hours and burn fewer candles at night. The U.K. instituted daylight saving time first in 1917, then it spread across the globe.
The U.S. Department of Energy claims that power usage drops by 0.5 percent during DST, saving the equivalent of close to three million barrels of oil.
Where is the rat race fastest, the places where the pace of life is faster than most others? Psychologists in the U.S. studied how quickly bank tellers made change, how fast pedestrians walked and the speed that postal workers spoke and found that the three cities where life is the fastest in the U.S. are Boston, Buffalo and New York. The slowest three are Shreveport, Sacramento and L.A.
In 1972, with technology of the day demanding greater accuracy for timing, more than 50 countries agreed on an international time system that was so accurate that it would lose only one second in 31.7 million years. The world’s most accurate clock today is in Colorado, at the National Institute of Standards and Technology. It measures vibrations of a single atom of mercury. The clock will not lose as much as one second in one billion years.
As noted above, the earth’s rotation is not so accurate, in fact it’s slowing down. Every few years international time systems must add a “leap second” to the year in order that the solstices and equinoxes remain around the same dates. The last year a leap second was added was 2008 (2008 was one second longer than most years, the additional second being added on New Year’s Eve).
When train travel became common in the 19th century, schedules had to be kept. As each community tended to have its own timekeeping system, there were usually two kinds of time–local time and railway time. Because this was too confusing, American railway systems forced the adoption of a national system of standardized time, in 1883. The forced synchronizing of timekeeping systems may have inspired Einstein’s thinking about relativity.
Einstein said that gravity slows the passage of time, so the less gravity influence you experience the slower time passes and the slower you age. That means that airplane passengers at high altitudes and people on the international space station, experiencing less gravity than those of us on the surface, should age faster by a few nanoseconds each day.
According to quantum physics, the shortest possible period of time should be 0.0000000000000000000000000000000000000000001 second.
Which reminds, me, I don’t have time to write more about this.
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[Primary source: Discover, March, 2009]