76 votes
Accepted

How did the ancient Greeks synchronize time?

In the particular case of Eratosthenes measuring the radius of the earth, it was done by observing the length of shadows at midday on the summer solstice, in cities that were north-south aligned (to ...
user avatar
  • 2,988
74 votes
Accepted

Why does the amount of days in an year on average of the Gregorian calendar only have 4 decimal places (365.2425)?

Why? Because there was no point. First, according to more modern astronomical measurements, the current length of the year is closer to about 365.2422 days, so they would've been relatively less ...
user avatar
64 votes
Accepted

When were 'time zones' (or at least time difference) discovered?

The concept of longitude was first developed by ancient Greek astronomers. Hipparchus (2nd century BCE) used a coordinate system that assumed a spherical earth, and divided it into 360° as we still do ...
51 votes
Accepted

Why does Edinburgh Castle's one o'clock gun fire at 1pm instead of, say, noon?

Edinburgh Castle's tourist attraction, the One O'Clock Gun, originated as an audible version of the Nelson Monument time ball. The Nelson time ball has dropped at 1:00 pm ever since it was installed ...
user avatar
  • 95.8k
43 votes

Why of all units is Time standard?

Most likely because it wasn't until the modern era that anyone really needed, or could achieve, much precision with time measurements. Prior to modern timekeeping, people pretty much lived on daily ...
user avatar
  • 109k
29 votes

When were 'time zones' (or at least time difference) discovered?

Time zones were not discovered, they were defined. Without time zones, you have the concept of solar noon. A time zone is an area where the solar noon of a central place (like a royal observatory) is ...
user avatar
  • 16k
24 votes
Accepted

How did people wake up on time before alarm clocks?

Most people just rose at dawn, or when the birds started their noise, like a rooster. Those few who really had to wake up earlier were usually woken up by 'specialists', like the Knocker up Letting ...
user avatar
  • 73.7k
20 votes

How old is the day of 24 equal hours?

From Scientific American: Hipparchus, whose work primarily took place between 147 and 127 B.C., proposed dividing the day into 24 equinoctial hours, based on the 12 hours of daylight and 12 ...
user avatar
  • 17.4k
19 votes

Why does the amount of days in an year on average of the Gregorian calendar only have 4 decimal places (365.2425)?

The Gregorian Calendar was introduced (to the Catholic World) in 1582, the result of preparation over the preceding five or so years. However the popularization of decimal fractions would wait another ...
user avatar
18 votes

Why of all units is Time standard?

All through history, people needed fair, repeatable measurement of physical quantities. How much grain am I buying? How much land do you have (so it can be taxed)? How much flour and water do I use ...
user avatar
  • 52.6k
17 votes
Accepted

How was the current month and day disseminated to the townspeople of Medieval Europe?

For the most part, church and celestial events. In particular, midsummer and midwinter and the equinoxes were both easy to detect and were important events, at least in the colder climates of Europe. ...
user avatar
17 votes

How did people wake up on time before alarm clocks?

An important point which no one has mentioned - for most people, the need to wake up 'on time' is a product of the industrial revolution so before that there was no need for alarm clocks. Waking up at ...
user avatar
  • 2,215
16 votes

How did the ancient Greeks synchronize time?

To add to the answer of PhillS: there was essentially no method of exact time synchronization in two remote places before 17th century. The method of observation at noon at two places only works UNDER ...
user avatar
  • 37.3k
13 votes

Why of all units is Time standard?

Why does everyone use seconds/minutes/hours today? These units were adopted in the west in ancient times, by the Greeks, who borrowed it from their middle eastern neighbors, the Babylonians, who had ...
user avatar
  • 6,739
13 votes

When were the first timezones established?

Sir Sandford Fleming invented Worldwide Standard Time between 1876 and 1879: After missing a train in 1876 in Ireland because its printed schedule listed p.m. instead of a.m., he proposed a single 24-...
user avatar
12 votes
Accepted

Where was the dateline before the concept of the International Dateline?

The general concept of a date line preexists Caroll. By the 17th century possible locations for the line had been proposed See Here. People living at the same general time also recognized the notion ...
user avatar
12 votes

What does BPE/PE in some archaeology journals stand for?

"BPE" stands for "Before Present Era", and is equivalent to the more familiar BP (Before Present = 1950). It is a new "standard" abbreviation that I have seen appearing over the last decade or so (...
user avatar
  • 76.2k
11 votes
Accepted

What time was it in Dawson Creek, BC at 1900-01-01 00:00:00 +0000?

What time was it in Dawson Creek, BC at 1900-01-01 00:00:00 +0000? The pedantically correct answer, based on the IANA Timezone Database, is that it was 1899-12-31 16:00:00 (-0800) at 1900-01-01 00:00:...
user avatar
  • 2,397
11 votes

When were 'time zones' (or at least time difference) discovered?

I point out that the survivors of the Magellan expedition were startled by a date discrepancy. Twenty crewmen died of starvation by 9 July 1522, when Elcano put into Portuguese Cape Verde for ...
user avatar
  • 16.7k
10 votes

When were 'time zones' (or at least time difference) discovered?

There is no recorded moment, but the time difference in places with different longitude was discovered as soon as people realized that the Earth is round, and that Sun rotates about it (or vice versa, ...
user avatar
  • 37.3k
9 votes
Accepted

What is the origin of Indian weekday names?

None of the Hindu mythological books or puranas mention the names of the week , today what we use as VAAR ( Ravi , Som , Mangal, Budh . Brihaspati, Shukra, and Shani ) are the translated version of ...
user avatar
9 votes
Accepted

Why does clock time start in the middle of the night?

Some societies use sunset as the end of one day, and the start of the next: this is recorded in Genesis, chapter 1; for example, the Athenians, or see the Jewish civil day Some traditional ...
user avatar
  • 6,739
9 votes

When did the current 7-day week cycle begin?

Timothy is somewhat correct with identifying Babylon, however the Babylonians only borrowed the system. Most of our time keeping dates all the way back to ancient Sumeria (2600BC-ish?) and is ...
user avatar
  • 2,689
9 votes

How did people wake up on time before alarm clocks?

Where I live in South Germany the village church rings its bells at 6 am every day. This used to be to wake people up to come to early service. Later when early service stopped being a thing they ...
user avatar
  • 666
8 votes

What is the origin of Indian weekday names?

The ancient Hindus did not regularly use "days of the week" (although they are attested). The reason for this was that the Hindu calendar before 1100 AD used mean times (called madhyama) and this can ...
user avatar
  • 37.2k
8 votes

How did people wake up on time before alarm clocks?

In some towns and cities people were woken by waits (also spelt waites). Waits, who were present in "every British town and city of any note", were (usually) salaried bands of musicians who had a ...
user avatar
8 votes

What does BPE/PE in some archaeology journals stand for?

BPE means Before Present Era. Now we know the words behind the acronym, we still don't know the meaning of those words. 21.12 dates Note: non-religious alternatives to BC (before ...
user avatar
  • 73.7k
7 votes
Accepted

When did humans start numbering years?

When did humans start to keep track of years with unique identifiers for each year? [...] My questions is: when was that "later point"? When did we start "numbering" the years to ...
user avatar
7 votes
Accepted

How did people in Athens 500 BCE refer to Homer's era?

Your question could mean a couple of different things. The ancient Greeks didn't date historical events by use of a calendar. They had local calendars to regulate events during the year, but: By ...
user avatar
  • 3,667
6 votes

How was the current month and day disseminated to the townspeople of Medieval Europe?

This question is very vague, but I assume you are asking about the Middle Ages in Western Europe, though there is no reason why it should not be about Byzantium, Islam, India, China or any other ...
user avatar
  • 9,473

Only top scored, non community-wiki answers of a minimum length are eligible