Tag Archives: time

Meanwhile, in Persia—

With only a jug of wine, a loaf of bread and thousands of calculations, Omar Khayyám works out a new calendar

ad1075. In Persia, using the Hindu-Arabic decimal system, Omar Khayyam introduced a new calendar. The length of the year was measured as 365.24219858156 days and is very accurate. It didn’t catch on in the West.

https://www.britannica.com/biography/Omar-Khayyam-Persian-poet-and-astronomer

Omar Khayyam


https://www.timeanddate.com/calendar/persian-calendar.html

Maimonides, Maimonides, there’s no one like Maimonides

Rabbi Moshe ben Maimon, or RAMBAM to his pals

Happy Hanukkah! It seems like a good time to post about Maimonides and Anno Mundi, or ‘in the year of the world’ in Latin.

Maimonides was a doctor, theologian, philosopher and legal scholar who studied the Hebrew Bible—what Christians call the Old Testament. He lived near Cairo, Egypt in the ad 1100s.

If you do any Bible study you’ll have realized that the Bible isn’t one book but a library of books. What makes Bible study challenging is trying to keep all the stories, laws, wisdom and poetry organized in your head.

Maimonides thought it would be a great idea to create a guide for studying the Bible. He focused on the 5 Books of Law, the Torah. These are Genesis, Exodus, Leviticus, Numbers and Deuteronomy. As he wrote his guide, the Mishneh Torah, he found that he needed a chronology—a timeline of the events that happened in those books. Maimonides used the list of generations of people found in Genesis and Numbers to work backward to calculate when the world was created. That exact date of October 7, 3761 bc is now generally accepted in Judaism.

The Anno Mundi timeline is a theological one. You can’t count backwards from Year One because Time itself didn’t begin until that year. Today we’re in the year am 5780. Anno Mundi and the Hebrew calendar are used in synagogues and Jewish communities around the world.

Maimonides was one of those great thinkers whose influence extended far beyond his own time and place. You can’t believe the amount of stuff he wrote. I’ve given you a mere glimpse of him, but you can read more about Maimonides here.

https://johnmanders.wordpress.com/2019/06/10/the-torah-and-linear-time/

https://en.wikipedia.org/wiki/Hebrew_calendar

https://www.chabad.org/library/article_cdo/aid/75991/jewish/Maimonides-His-Life-and-Works.htm

UPDATE: The current year has been changed to am 5780. Thanks, Jeffrey!

Postcards!

postcard.shot

I got postcards! They have my weird hand-lettering and a lovely astrolabe on the front. The back tells how to find The Western Civ User’s Guide on the internet. I’ll be sending these out to promote my blog and this history I’m writing. The plan is to eventually turn it into a printed book.

If you’d like me to send you a postcard, shoot me an email at john@johnmanders.com.

I do appreciate you guys who read my posts. Thanks for spreading the word.

By the way, these were printed at Best Printing in Oil City, Pennsylvania. Nice job, Licia!

Back to the beginning of The Western Civ User’s Guide to Time & Space

Title type for my groundbreaking soon-to-be bestseller

Fooling around with lettering. It needs a little tweaking. Some strokes ought to be heavier, maybe. I’m trying to hold onto the energy of my sketch. I’m not sure if I like this yet. Let it sit for a while.

Hey, what time is it?

We’ve talked about telling time with sundials and water clocks and hourglasses. Those things are a headache to carry around. Mechanical clocks, like a pendulum clock, wouldn’t be invented until 1637. What if you’re traveling around in ad 800—how do you know what time it is?

One way to tell time was this fantastic little device called an astrolabe.

This sketch is based on a beautiful antique brass astrolabe.

Wherever you happen to be, if you can see the Sun or the stars, you can tell the time if you’re carrying an astrolabe with you. The main feature of an astrolabe is a flat map of the sky—with the stars and planets on a grid. The grid—called a climate—shows the sky as it appears in your part of the world. It’s circular and fits into a circular frame, called the mater (Latin for ‘mother’). On top of the climate is the rete (Latin for ‘net’), an openwork circular plate with pointers that you can line up to point at the Sun or a specific star on the climate. On top of that is a sighter—a straight arrow kind of piece. All these spin on the same axis. You pick a star, adjust the rete to point at your star on the climate, and hold up the astrolabe and sight the actual star along the sighter. When the sighter lines up with the star, you can read the time with remarkable accuracy. Here’s a video showing how it’s done. This guy even made his own astrolabe. And here’s more.

Here’s a website that explains how to use an astrolabe and even gives you pdfs you can download and print to make your own.

It’s better than bad, it’s good

There is a mention of an hourglass in a ship’s inventory in the 1300s.

When you need to know where you are at sea, this is what you have to go on.

At sea, it’s difficult to know exactly where you are. No landmarks. No way to tell how far you are from land. Sailors had to be creative. To figure out distance, they used time.

Sailors liked the hourglass because it isn’t as affected by a ship’s bouncing around on the waves as a water-clock would be—it still marks an hour accurately. Smaller sandglasses with less sand mark shorter periods of time. Sailors could judge how fast their ship were traveling by ‘casting the log.’ They had a length of line—heavy cord—with a piece of wood (the log) tied to its end, and knots tied in it at regular intervals. They’d throw the log into the sea and turn the glass at the same time. The log dragged behind and pulled the line with it. When the sand ran out, they’d nip the line and count how many knots had run out. Number of knots = distance traveled in a set space of time.

If you know how fast you’re traveling, you can make a guess how far you traveled in an hour or a day or a week. This is how the sailors used to calculate where they were on the ocean.

Casting the log is said to have been invented in the 1500s. The first evidence of a ship’s log-book is from the 1600s. This is a guess, but it seems to me that the log-book would have been originally a record of the ship’s speeds—that eventually became a record of any important events that happened aboard the ship. With time, ‘log-book’ got shortened to ‘log.’

Today, people who post regularly on the worldwide web refer to their sad ramblings as a ‘web-log’ or ‘blog’ for short. Spare a thought for us poor, attention-starved souls.

Here’s an excellent video about casting the log.

https://www.britannica.com/technology/log-nautical-instrument
https://en.wikipedia.org/wiki/Chip_log
https://www.archives.gov/research/military/logbooks/naval-deck-logs.html

The secret origin of “log in”

More about time and distance.

Read this now! Time is running out!

Hourglasses are good timers that are easy to use, so they’ve been part of people’s lives for centuries. My mom used to have a little one that measured 3 minutes—just right for boiling an egg.

The hourglass became a symbol for time itself, and just how quickly it seems to pass. Go into an old cemetery and you might see one carved into a tombstone—eeek!

On some computers a little icon of an hourglass shows up to tell you that your program is still loading.

By golly, I would have committed murder to own that Wizard of Oz hourglass when I was an art student, How about the lucky prop artist who got to design it!

If you ever saw the old Wizard of Oz movie with Judy Garland, you’ll remember that terrifying big hourglass that belonged to the Wicked Witch of the West. Here’s a website that tells how hourglasses are made. This one’s good, too.

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Hourglasses

An hourglass is a device that measures time. It’s two glass bulbs joined together by a skinny neck. There’s sand inside, so when you set the hourglass with the sand-filled bulb on top, the sand trickles through the neck into the empty bulb below. The hourglass maker put in exactly an hour’s worth of sand, so when the top bulb is empty, one hour has passed. The whole contraption is contained in a frame so it can be stood on either end.

Hourglassses are sometimes called ‘sand clocks,’ but they’re timers. Remember the early Egyptian water clocks? They were timers, too, until Ctesibius figured how to make clocks out of them.

Legend says that a French monk called Liutprand (Lee-UT-prond) invented the hourglass in the 8th century ad. There doesn’t seem to be solid evidence to support or deny that. Charlemagne is supposed to have owned a 12-hour hourglass—Liutprand was French, Charlemagne was French, so maybe there’s a connection? And I guess I’d have to admit that at 12 hours, that hourglass was a clock.

https://www.guinnessworldrecords.com/world-records/first-hourglass

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Everything AD does but backwards, in high heels

Long ago, in the dim misty recesses of history, there was a famous dance couple: Fred Astaire and Ginger Rogers. Their dance routines were stylish and glamorous—and captured in movie musicals so you can still watch them. Fred and Ginger made dancing look easy by putting in a lot of rehearsal time.

Ginger once joked that not only did she do everything Fred did, but she did it backwards, in high heels.

If you thought it was hard to figure out how the centuries are referred to in Anno Domini, how do we ever count back the centuries Before Christ? We live in the 2000s and call it the 21st Century. The 21st Century ad starts with 2001 and ends with 2100. How does that work in bc, where you count backwards?

Let’s pick a century. How about the 4th century? The 4th century Anno Domini started the first day of ad 301 and ended the last day of ad 400. It’s just the opposite in bc. The 4th century Before Christ started the first day of 400 bc and ended the last day of 301 bc.

Are you getting a headache yet?

Back to the beginning of The Western Civ User’s Guide to Time & Space.

What century is this anyway?

All the years in this century start with 20… So how come it’s called the 21st Century?

Well, first of all, not all the years start with 20… The very last year of this century, its 100th year, will be 2100.

It works just like your age. Are you 12 years old? That means you’re in your 13th year. When you’re in your 21st year, you’ll be 20 years old until the very last day—the day before your birthday. Then on that birthday you’ll be 21 years old and in your 22nd year.

Anno Domini is in its 21st century, and is 2019 years old. December 31, 2100 will be the last day of the 21st Century. On January 1, 2101, AD will be in its 22nd century.