Ever felt like cursing whoever came up with the seven-day week? Why choose an awkward prime number that seems to lack any correlation to the average 30-day month and 12-month year? Well, look no further, as those responsible for all three of these values are identified here.

With the naked eye, five planets (Mercury, Venus, Mars, Jupiter and Saturn) are visible from Earth. Combining this with the sun and the moon, you have seven celestial bodies, and ergo a seven-day week. The Babylonians believed that the night sky was the channel of communication between the heavens and the earth. In order to honour this gift, they paid very close attention to what was going on above our heads and allowed it to dictate practically everything from timekeeping to religion. Often heralded as the beginnings of true civilisation, their astronomical culture has had a significant impact on modern day-to-day life.

“The Babylonians believed that the night sky was the channel of communication between the heavens and the earth”

They took meticulous observations over extended periods which allowed them to identify emerging patterns that could benefit the whole civilisation. The sky varies on a yearly cycle, meaning certain stars would appear before seasonal weather patterns, which the Babylonians could use to determine their agricultural cycle. These celestial ‘events’ were seen as omens, and if the floods and dry spells could be predicted based on them, why not other things? Alongside records of the sky, smaller events such as political and social ones began to appear in the cuneiform tablets.

“Alongside records of the sky, smaller events such as political and social ones began to appear in the cuneiform tablets”

Taking this hypothesis to the extreme, they attempted to predict the course of their own personal lives and their personalities. Essentially, the Babylonians allowed their fates to be written and read in the stars, and hence the practice of astrology was born. In 410 BCE, the position of the planets was noted at a child’s birth and the tablet reads: ‘things will be good for you’, marking the first known horoscope. It’s not a stretch to imagine a standard Babylonian horoscope probably read slightly differently to the typical modern day one – more maize, less ‘expect big changes in your love life’. They are also responsible for not only the zodiac but also the identities of several of the signs, with Capricorn being the earliest named and noted constellation.

“The Babylonians allowed their fates to be written and read in the stars, and hence the practice of astrology was born”

Love it or hate it, our lives are unavoidably saturated with maths, and we owe several intrinsic ideas to the Babylonians. Through their extreme number of observations, they displayed the first recorded attempts to analyse nature using maths, and so their mathematical ability was developed to support their astronomy. They were the first to introduce positional notation using tens, hundreds and thousands, far more practical than the clunky Roman numeral system. While we use the base number of ten because of our fingers, Babylonian maths was characterised with multiplication and division tables to deal with a larger base number of 60. It is believed that they chose 60 due to its high number of factors, with a similar decision giving us 360º in a full rotation. They had estimated a value of pi as 3.125, could solve quadratic and cubic equations and could calculate the hypotenuse of a right-triangle – Pythagoras eat your heart out! Greek astronomer and mathematician Hipparchus is often credited with the invention of trigonometry, but evidence has exposed that the majority of the numbers he based his theories on came from Babylonian tablets, and in 2017 Australian researchers claimed a tablet from the 2nd millennium BCE contained a trigonometric table, so perhaps he was introduced to the idea from another source.

In conjunction with the seven-day week, we can thank the Babylonians for our whole calendar. Their choice of base number also provides us with 60 seconds in a minute, 60 minutes in an hour, 24 hours a day and 12 months in a year. The study of the moon has provided us with the roughly 30-day month structure as one lunar cycle is around 29.5 days, and this influence formed the basis of both the Jewish and Christian calendars. Unfortunately, this did provide a 354-day year, but they reconciled this with a 13th month every 3 years, which operates on the same principle as our leap year.

In summary, next time mercury is in retrograde and you’re stressed out about your Thursday-Wednesday because there’s not enough hours in a day, you know who to blame.