Documents
Pictures
Videos
Forum
 
 

A Brief History of Timekeeping


A Brief History of Timekeeping
“To be human is to be aware of the passage of time; no concept lies closer to the core of our consciousness.” For millennia, humans have sought to make sense of time, to visualize it, to ride its arrow, to hack it, to understand biological connection to it. “Time is the very foundation of conscious experience,” writes Dan Falk in In Search of Time: The History, Physics, and Philosophy of Time (public library). “To be human is to be aware of the passage of time; no concept lies closer to the core of our consciousness.” And yet that awareness has a long history of friction — to mark and measure the passage of time has proven remarkably challenging. For instance, Falk traces the evolution of the calendar, our dominant system for collectively experiencing time: The Gregorian calendar is one of the most successful ideas in the history of civilization. (Richard Dawkins might call it a successful ‘meme’ — a unit of cultural information that propagates over time.) The Gregorian calendar is not the only timekeeping system invented by humankind — nor, as we’ll see, is it even (by some measures) the most accurate. But its story is a noteworthy one, an achievement centuries, even millennia, in the making. We saw in the previous chapter how early humans were captivated by — and began to follow — the regular motions of the night sky. By the time of the great ancient civilizations, such systematic observation had become a virtual industry; every culture would develop some sort of calendar for mapping out the year, based on their observations of the heavens and their own particular needs and priorities. The one that rules today — the Gregorian Christian calendar — exploits ideas from many different cultures, each with a unique perspective on the significance of the heavenly bodies and unique solutions to the problem of tracking their motions. In this chapter we’ll take a look at some of the challenges confronting would-be calendar makers through the ages, as they tried to tame the myriad of motions displayed by the sun, moon, and stars.   Like much of knowledge, the contemporary calendar, it turns out, is an additive innovation: The first rudimentary steps toward tracking those celestial motions, as we’ve seen, may have occurred as early as the Paleolithic period. But it is only with the rise of the first civilizations — marked by complex, agriculture-based urban settlements with full-blown writing systems — that we can be certain that people were keeping track of days, months, and years. Making sense of those celestial cycles, however, is complicated by the fact that neither the number of days in the lunar cycle nor the number of lunar cycles in a year is a nice round number (indeed, not even a whole number). The lunar month, as mentioned earlier, is about 29 ½ days long (actually 29.5306); the average solar year (also known as the “tropical” year) is about 365 ¼ days long (actually a smidgeon less, at 365.2422 days). That these cycles did not fit neatly into one another was well known: back in the fifth century B.C., the Greek poet Aristophanes, in his play The Clouds, had the moon complaining that the days refused to keep pace with her phases.   These incongruent cycles is where it gets interesting: Try dividing the length of the year by the length of the lunar month, and again you get a fractional number, greater than 12 but less than 13 — the true figure is close to 12.3683. Over the millennia, different civilizations tried every possible trick for reconciling these incongruent cycles. Some simply rounded the length of the month up to 30 days, a practice adopted by the ancient Sumerians; 12 such months yield a 360-day year, just 5 days (roughly) short of the true solar year. Others used a more precise length for the lunar cycle and then assumed there were exactly 12 months in a year: the result is a year that is 354 days long — 11 days short (roughly) of the true solar year. Adopt such a calendar, and each New Year’s celebration will be 11 days earlier than it was the year before. A midsummer celebration would become a midwinter celebration after just 16 years. Any calendar system that uses the phases of the moon to track the months but also attempts to reconcile those months with the cycle of the seasons is called a luni-solar calendar. The Babylonians adopted one such system. A new month was determined by the first sighting of the crescent moon in the western sky — a practice that continues in Muslim nations to this day (notice how many Muslim nations feature the crescent moon on their flag). To keep the months in step with the solar year, the Babylonians employed a cycle in which seven 13-month years alternated with 12 years of just 12 months. The result was a 19-year cycle known as the Metonic cycle, after the Greek astronomer Meton of Athens, who lived in the fifth century B.C. (Meton discovered that 235 lunar months amount to almost exactly the same interval as 19 solar years; a calendar based on this cycle would deviate from the true solar year by just 1 day every 219 years.) Beginning in the second millennium B.C., the extra month would be added — “intercalated” — following either the sixth month (Ululu) or the twelfth month (Addaru) of the Babylonian calendar. We have a record dating from the nineteenth century B.C. of King Hammurabi’s decree on just such an adjustment: This year has an additional month. The coming month should be designated as the second month Ululu, and wherever the annual tax has been ordered to be brought in to Babylon on the 24th of the month of Tashritu it should now be brought to Babylon on the 24th of the second month of Ululu. The Jewish calendar is closely modeled on the Babylonian. (The mutual influence of the two cultures can be traced back to the sixth century B.C., when Babylon, under Nebuchadnezzar II, conquered Jerusalem; the Jewish people spent the next 70 years or so in exile.) The Jewish calendar, like the Babylonian, is built on the nineteen-year Metonic cycle, with its combination of 12-month and 13-month years. Within that cycle, the lengths of certain months can also vary, so that a “regular” year can be 353, 354, or 355 days long, while a leap year (containing an extra month) can be 383, 384, or 385 days long. (This is why the date of Jewish holidays such as Hanukkah leaps around so much with respect to the Gregorian calendar.) The rest of In Search of Time, a fine addition to these essential books on time, is just as fascinating an untangling of the basic fabric of our existence, exploring everything from the science of time travel to the persistence and mechanisms ofmemory to the inevitability of impermanence. This article is reprinted with permission from Maria Popova. She is a cultural curator and curious mind at large, who also writes for Wired UK, The Atlantic and Design Observer, and is the founder and editor in chief of Brain Pickings (which offers a free weekly newsletter).


Author: Maria Popova # BivuNoku86
Science & Technology2012-08-06
-
 50%  ( 2 people voted )
+

Name:

What is tripcode?
A tripcode is a hashed password, by which you can be identified by others. This does not require registration and you will be still anonymous. Password is not stored on the server.
Tripcode:
(recommended)
What is this?
Anti-spam protection against robots. Please write this two numbers in decimal form.
nine   three
(write in decimal)

By submitting this form, I Agree to the Terms and Conditions. Click here for whole text of Service Agreement.

Optional URL of video, picture or google map:








Best of week
Most Popular

15 New Year’s Resolutions Every Person Should Actually Make


15 New Year’s Resolutions Every Person Should Actually Make
Making New Year’s resolutions and staying committed to them can be a challenging thing for a lot of people. And even though I think it’s important to have a vision, a clear direction or goal ...
Why True Love Is Eternal
9 Ways to Feng Shui Your Office Desk for Wealth and Success
9 Ways to Feng Shui Your Office Desk for Wealth and Success

4 Things You Can Learn from Visiting an Ashram


4 Things You Can Learn from Visiting an Ashram
It is coming up on the 1st anniversary since my first visit to an ashram. I took a trip by myself in January of 2011 not knowing what to expect to this place called Yogaville. The drive was about 4 ...
Why Positive Thinking Won’t Guarantee You Positive Results
Have You Seen the Wizard?
The Poorest & Most Generous President in the World

The Urgency of Smiling


The Urgency of Smiling
A dear friend recently shared a homemade smile card experience with me: Ever since yesterday, I've had this urge to pay forward someone's coffee. But I didn't have a smile card.
Developing: Drug that Sends Cancer Cells to Sleep to Stop Them Spreading
Your Health Is Bigger Than Your Body
Don't Worry Be Healthy

The Elephant Whisperer


The Elephant Whisperer
Lawrence Anthony, the acclaimed South African conservationist passed away this March. His funeral turned out to be as extraordinary as his life. Two herds of wild elephants traveling single file ...
The City That Ended Hunger
Ancient Wisdom From the Second Most Translated Book in the World
Change is Coming

New Hypersonic Plane Could Fly Between New York and Tokyo in 90 MINUTES


New Hypersonic Plane Could Fly Between New York and Tokyo in 90 MINUTES
XCOR Aerospace claims its Lynx spacecraft can travel at a speed of more than 2, 500 mph and dozens of miles above the earth before safely landing at an airport. It would be the fastest commercial ...
The Secret Powers of Time
The Odd Truth About Other People's Problems
12 Scientifically Proven Steps to Happiness

Finding A Job..when You Least Expect It!


Finding A Job..when You Least Expect It!
So I haven't held a job since April of 2011 due to multiple health issues. I currently draw disability but am having trouble finding money at the end of the month so I decided I would look for a ...
What If Money Were Not an Issue?
Is Time Really Money?
After 25 Years of Trying, Two Friends Win $14 million Jackpot

The Fine Balancing Art of Yin and Yang


The Fine Balancing Art of Yin and Yang
In the past 2 years I have experienced the delights of visiting Thailand and being bowled over by their inherent sense of beauty and creativity to their humble way of life and their desire to please...
The Action of Light
A Quick Guide To The Art of Listening
An Incredible Graduation Gift from Dad

Drew Brees is Donating $1MILLION for Superstorm Sandy Relief


Drew Brees is Donating $1MILLION for Superstorm Sandy Relief
The New Orleans Saints quarterback told CBS' 'Person to Person' in an interview to air on Friday that the donation will come through the Dream Foundation he runs with his wife, Brittany. Brees says ...
High School Football Team Lends Special-Needs Girl Tactical Defense
18 Holes Of Happiness
Gold Medal Gives Ugandans New Hope

Grandmother Power: A Global Phenomenon


Grandmother Power: A Global Phenomenon
Today’s grandmothers are different from mine. My grandmother lived a mile away. I played under her bushes where spring violets grew.
The Millionaire Janitor
What Motivates Philanthropists?
6-Year-Old Nico: Halloween's Real Life Hero

11 Must-Read Books for Young Leaders


11 Must-Read Books for Young Leaders
Recently, I wrote that leaders should be readers. Reading has a host of benefits for those who wish to occupy positions of leadership and develop into more relaxed, empathetic, and well rounded ...
10 Lessons to Learn from Storm Sandy and Natural Disasters
The Beauty of Questions
Finding Humility through Wisdom
Digest

15 Things You Should Add on Your Daily To Be List


15 Things You Should Add on Your Daily To Be List
I have always loved this quote from Wayne Dyer: “I am a human being, not a human doing. Don’t equate your self worth with how well you do things in life. You aren’t what you do. If you are ...
15 Things You Should Add on Your Daily To Be List
15 Things You Should Add on Your Daily To Be List
15 Things You Should Add on Your Daily To Be List


Hĺbkové čistenie pleti v Bratislave Hĺbkové čistenie pleti Bratislava Kozmetika Bratislava | Čistenie pleti hĺbkové v Bratislave Kozmetický salón Bratislava Kozmetika Bratislava Beauty salon Bratislava | private label cosmetics, skin care manufacturer, custom made cosmetic, custom made cream, custom lip stick lip balm | dôležité informácie denné správy aktuálne spravodajstvo | good positive news inspirational stories articles
Version:1.23 2013-07-17 Generated in 0.0364 s