Thursday, November 29, 2018

A Crutch

We must use time as a tool not as a crutch.” (John F. Kennedy)

Time is the most used noun in the English language, but it remains a mystery. The nature of time has fascinated humans from the earliest point of it being measured. People have always struggled with how to measure time (since its inception). Today’s countries still deal with many unique time zone challenges to try to right time.

Human beings have tried changing how we approach weeks, months, and years. It always comes back to the Earth rotating on its axis every 24 hours, and going around the sun every 365.25 days. Here are some facts related to time that you may not know:

1.   A lifespan is a billion heartbeats:  Complex organisms die. Sad though it is in individual cases it’s a necessary part of the bigger picture. Life pushes out the old to make way for the new. There exist simple scaling laws relating animal metabolism to body mass. Larger animals live longer; but they also metabolize slower, as manifested in slower heart rates.

These effects cancel out so that animals from shrews to blue whales have life spans with just about equal number of heartbeats  ( about one and a half billion). In that very real sense, all animal species experience “the same amount of time.

2.   A second is not one-sixtieth of a minute: While there are 60 seconds in a minute, that's not why a second is how long it is. Since 1967, the International Committee for Weights and Measures has measured a second as "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.”

It can also be measured as a fraction of a year, 1/31,556,925.9747th of a year, to be exact. However, a second has been measured as 1/60th of a minute since the Babylonians in 300 BCE. 

3.   Daylight Saving Time first originated with an Englishman: In 1784, Benjamin Franklin jokingly proposed waking the people of Paris up earlier during the summer so they could toil extra hours in the fields and not have to waste candles. Franklin's satirical idea was just that, and was never intended to catch on with the public.

It would take over 100 years for daylight saving time to actually become a workable idea, thanks to English builder William Willett, who enjoyed riding horses and campaigned for clocks to be moved back in the summer to give people more daylight.

4.   Everyone experiences time differently: This is true at the level of both physics and biology. Within physics, we used to have Sir Isaac Newton’s view of time, which was universal and shared by everyone. But then Einstein came along and explained that how much time elapses for a person depends on how they travel through space as well as the gravitational field.

 From a biological or psychological perspective, the time measured by atomic clocks isn’t as important as the time measured by our internal rhythms and the accumulation of memories. That happens differently depending on whom we are and what we are experiencing. There’s a real sense in which time moves more quickly when we’re older.

5.   It took 1500 years and a pope to get the calendar correct: Early Christians adopted the Julian calendar and assumed that all years were 365.25 days long. However, this is about 10-11 minutes too long. Those extra minutes began to add up, and by the 1500s, the calendar was off by over a week.

The spring equinox was tied to the date of Easter, and these two events had drifted farther apart over the centuries. In 1563, the Council of Trent under Pope Gregory XIII prepared a plan to add days to the calendar to correct the sync issues, and in 1582, ten days were added.  However, it took centuries for the Gregorian calendar to be universally adopted.

6.   Not only do we have leap days, we have leap seconds: To help synchronize atomic clocks with the earth's actual rotation, which is imperceptibly slowing, leap seconds are occasionally added to the 24-hour day. There have been 26 leap seconds added to the clock since the first one in 1972. However, this doesn't mean that all of our days are now half a minute longer - only the particular days containing a leap second were one second longer. The last one was in June 2015.

 
7.   The past and future are equally real: This isn’t completely accepted, but it should be. Intuitively we think that the “now” is real, while the past is fixed and in the books, and the future hasn’t yet occurred. But physics teaches us something remarkable: every event in the past and future is implicit in the current moment.

 
8.   The Soviet Union tried a five-day week and it failed: In 1929, a Soviet functionary proposed changing from the seven-day Gregorian calendar to a five-day week, in order to not have weekends with lowered production. The idea caught fire with Stalin, and he declared that all manufacturing and commercial enterprises must switch to the "continuous" week, with workers assigned a number and color that would correspond to their days off.

An added benefit was to remove the shared worship day from the calendar, moving the country further away from organized religion. The effect was to isolate workers and families, who would be assigned different days off, and get little or no time for coordinated activities. Families broke down under the strain, and the experiment was ended in less than two years.

Even then, the Supreme Soviet couldn't resist screwing around with the calendar, and the next eight years were spent on a calendar of five weeks per month, six days per week, with the sixth day being a shared day off. That lasted until June 1940.

9.   Time exists: Time organizes the universe into an ordered series of moments. The real question is whether or not time is fundamental, or perhaps emergent. We used to think that “temperature” was a basic category of nature, but now we know it emerges from the motion of atoms. When it comes to whether time is fundamental, the answer is: nobody knows.

 
10.       You live in the past: Use one hand to touch your nose, and the other to touch one of your feet, at exactly the same time. You will experience them as simultaneous acts. But that’s mysterious. It takes more time for the signal to travel up your nerves from your feet to your brain than from your nose.
 
The reconciliation is simple: our conscious experience takes time to assemble, and your brain waits for all the relevant input before it experiences the now.  Experiments have shown that the lag between things happening and us experiencing them is about 80 milliseconds.

11.       Your memory isn’t as good as you think: When you remember an event in the past, your brain uses a very similar technique to imagining the future. The process is less like “replaying a video” than “putting on a play from a script.” If the script is wrong for whatever reason, you can have a false memory that is just as vivid as a true one. Eyewitness testimony, it turns out, is one of the least reliable forms of evidence allowed into courtrooms.

 “No use thinking of the past for its gone, don't think of the future because it has to come, think of the present because that’s where you are.” (Kazi Shams)[i]




[i] Sources used:
·        Ten Things Everyone Should Know About Time” by Sean Carroll
·        “Things You Didn't Know About Time” by Mike Rothschild
 

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