If the Earth is 4.5 billion years old, why is it 2023? This is a question that may have crossed your mind as you consider the vastness of time and the relatively short history of human civilization. The answer lies in the way we choose to measure and number the passing of years.
The Earth is indeed around 4.5 billion years old, as estimated by scientists using a variety of methods. However, the system of numbering years that we use today only goes back a few thousand years. The system we use is based on the Christian era, also known as the Common Era or Anno Domini (AD). This system counts the years since the birth of Jesus Christ, with the year 1 AD being the year of his birth. Therefore, the year 2023 AD is exactly 2023 years after the year 1 AD.
But why do we use this system? The numbering of years based on the Christian era was first proposed by the monk Dionysius Exiguus in the 6th century AD. Before this, different cultures had their own systems for numbering years. Dionysius proposed his system as a way to standardize the dating of historical events across different cultures. It wasn’t until the 8th century that the system was widely adopted by the Western world, and it wasn’t until the 11th century that it became the dominant system for numbering years.
So, while the Earth may be much older than the 2023 years that have passed since the birth of Jesus Christ, our current system of numbering years only goes back a few thousand years. This is why it is currently the year 2023. It’s a way of keeping track of the passing of time, and a way of placing ourselves in the larger context of human history.
Is It BC or AD?
In addition to the Common Era (CE) or Anno Domini (AD) system, there is also the Before Common Era (BCE) or Before Christ (BC) system for numbering years. This system counts the years before the birth of Jesus Christ, with the year 1 BC being the year before his birth. Therefore, the year 2023 AD is the same as the year 4046 BC.
The BCE/BC system is often used as an alternative to the AD/CE system, particularly in contexts where the reference to Jesus Christ as the starting point for numbering years may be considered inappropriate or unnecessary. Both systems are used widely around the world, and it is generally up to the individual or organization to choose which system to use.
One important difference between the AD/CE and BC/BCE systems is the way in which “0” is counted. In the AD/CE system, the year 1 AD is immediately followed by the year 2 AD. There is no year “0” between 1 BC and 1 AD. This means that the year 1 BC is immediately followed by the year 1 AD. In contrast, the BC/BCE system includes a year “0” between 1 BC and 1 AD.
When using the Before Common Era (BCE) or Before Christ (BC) system to number years, it’s important to understand that the closer you get to the birth of Jesus Christ, the lower the year number becomes. This can be confusing at first, as we tend to think of time as moving forward and of more recent events having higher numbers.
For example, an event that took place in 100 BC is more recent than an event that took place in 200 BC. This is because 100 BC is closer to the year 1 BC (the year of Jesus’ birth) than 200 BC is. Similarly, an event that took place in 1 BC is more recent than an event that took place in 2 BC.
It’s also important to note that the BCE/BC system includes a year “0” between 1 BC and 1 AD (the year of Jesus’ birth). This means that the year 1 BC is immediately followed by the year 1 AD. In contrast, the Anno Domini (AD) or Common Era (CE) system, which counts the years after the birth of Jesus, does not include a year “0”. The year 1 AD is immediately followed by the year 2 AD.
To give an example of how the BCE/BC system works, let’s consider the following timeline of events:
- 250 BC: An event takes place.
- 100 BC: A different event takes place.
- 1 BC: Yet another event takes place.
In this timeline, the event that took place in 1 BC is the most recent, followed by the event in 100 BC, and then the event in 250 BC. It’s important to understand that the BCE/BC system counts backward from the birth of Jesus, and the lower the year number, the more recent the event.
How About the Calendar Year?
The length of a year – the time it takes for the Earth to make one orbit around the sun – is approximately 365.24 days. However, the length of a year as defined by a calendar – a system used to organize and mark the passing of time – is not always exactly 365.24 days.
The ancient Egyptians were among the first to develop a calendar based on the solar year. They divided the year into 12 months of 30 days each, with an additional 5 days added on at the end. This resulted in a year that was 365 days long, which is quite close to the actual length of the solar year.
Other ancient civilizations, such as the Babylonians and the ancient Greeks, also developed calendars based on the solar year. However, their calendars were not as accurate as the Egyptian calendar, and they often included additional months or days to keep the calendar in line with the seasons.
It wasn’t until the Julian calendar, introduced by Julius Caesar in 45 BC, that a calendar with a year of exactly 365 days became widely used. The Julian calendar was an improvement over earlier calendars, but it was still not perfectly accurate. It introduced the concept of a leap year, with an extra day added to February every 4 years to account for the extra quarter day in the solar year. This resulted in a year that was 365.25 days long, which is very close to the actual length of the solar year.
The Gregorian calendar, which is the most widely used calendar today, was introduced in 1582 as a further refinement of the Julian calendar. It slightly adjusted the rules for determining leap years, resulting in a year that is 365.24 days long – much closer to the actual length of the solar year.
How About The Names Of The Month Of The Year?
The names of the months of the year have a long and interesting history. Most of the month names we use today are derived from Roman mythology and the calendar of the Roman Republic.
The Roman calendar originally had only 10 months, with the year beginning in March. The months were named Martius, Aprilis, Maius, Junius, Quintilis, Sextilis, September, October, November, and December. The names of the first six months were based on the names of Roman officials, with Martius named after the god of war, Mars, and Aprilis named after the goddess of love, Venus. The last four months were named after their position in the calendar, with September being the seventh month, October being the eighth month, November being the ninth month, and December being the tenth month.
The Roman calendar was later modified to include two additional months, January and February. January was named after the god of beginnings and gates, Janus, and February was named after the purification ritual Februa. The names of these two months were added to the end of the calendar, so the year still began in March.
The Roman calendar was used throughout the Roman Empire, and its month names were eventually adopted by other cultures and languages. However, the month names were modified to fit the local language and customs. For example, the month of September, originally the seventh month in the Roman calendar, became the ninth month in many cultures due to the addition of two new months at the beginning of the year.
Names Of the Days of the Week
Most of the day names we use today are derived from the names of the gods and planets in Roman mythology.
The Romans divided the week into seven days, with the first day of the week being Sunday and the last day being Saturday. The names of the days were as follows:
- Sunday (dies solis): Named after the sun, which the Romans believed was a deity.
- Monday (dies lunae): Named after the moon, which the Romans believed was a deity.
- Tuesday (dies Martis): Named after Mars, the god of war.
- Wednesday (dies mercurii): Named after Mercury, the messenger of the gods.
- Thursday (dies jovis): Named after Jupiter, the king of the gods.
- Friday (dies veneris): Named after Venus, the goddess of love.
- Saturday (dies Saturni): Named after Saturn, the god of agriculture.
The Romans based their calendar on the movements of the sun, moon, and planets, and believed that each day of the week was ruled by a particular deity. The names of the days of the week reflected this belief, with each day named after a deity associated with a celestial body.
The Roman calendar and the names of the days of the week were eventually adopted by other cultures and languages. However, the day names were modified to fit the local language and customs. For example, the day of the week named after the sun in Latin, dies solis, became dimanche in French and Sonntag in German, both of which mean “Sunday.”