Happy Phi Day: The Last Day to Match the Golden Ratio for a Century

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iStock

Math whizzes may have noticed something particularly pleasing about today's date. According to Bloomberg, June 1, 2018 (formatted as 1/6/18 in many parts of the world) is Phi Day, a date that matches the first four digits of the golden ratio.

Represented by the 21st letter of the Greek alphabet, the golden ratio, which comes out to roughly 1.618 when rounded, is the number you get when you divide a line into two parts so that the longer part divided by the smaller part is the same as the total length divided by the longer part (or simplified: When the smaller is to the larger as the larger is to the whole).

Non-mathematicians might know it better as the number that appears constantly in nature, art, and architecture. The Pyramids at Giza, Leonardo da Vinci's "Vitruvian Man," nautilus shells, sunflower seed heads, and spiral galaxies all feature the golden ratio.

The golden ratio is also closely related to the famous Fibonacci sequence. In this series of numbers beginning with zero or one, each subsequent number equals the sum of the previous two (i.e., 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, etc.). The ratio of any two successive numbers in this sequence comes very close to the golden ratio. Shapes made with Fibonacci dimensions are considered pleasing to the eye, which is why they so often appear in art, either unintentionally or by design.

Unlike other math holidays such as Pi Day, Phi Day only comes once a century. You can celebrate the once-in-a-lifetime occasion by taking a walk outside and seeing how many examples of the golden ratio you can spot in your neighborhood.

[h/t Bloomberg]

If March 15 Is the Ides of March, What Does That Make March 16?

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iStock.com/bycostello

Everyone knows that the soothsayer in William Shakespeare's Julius Caesar was talking about March 15 when he warned the Roman emperor to "beware the Ides of March." We also all know Caesar's response: "Nah, I gotta head into the office that day." But if March 15 is the Ides of March, what does that make March 16?

At the time of Caesar's assassination, Romans were using the Julian calendar (introduced by Julius Caesar himself). This was a modified version of the original Roman calendar, and it is very similar to the one we use today (which is called the Gregorian calendar). A major difference, however, was how Romans talked about the days.

Each month had three important dates: the Kalends (first day of the month), the Ides (the middle of the month), and the Nones (ninth day before the Ides, which corresponded with the first phase of the Moon). Instead of counting up (i.e., March 10, March 11, March 12), Romans kept track by counting backwards and inclusively from the Kalends, Ides, or Nones. March 10 was the sixth day before the Ides of March, March 11 was the fifth day before the Ides of March, and so on.

Because it came after the Ides, March 16 would’ve been referred to in the context of April: "The 17th day before the Kalends of April." The abbreviated form of this was a.d. XVII Kal. Apr., with "a.d." standing for ante diem, meaning roughly "the day before."

So, had Julius Caesar been murdered on March 16, the soothsayer's ominous warning would have been, "Beware the 17th day before the Kalends of April." Doesn't have quite the same ring to it.

This story first ran in 2016.

Google Engineer Calculates Pi to 31 Trillion Digits, Sets New World Record

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iStock.com/sovika

Pedantic math whizzes may insist that Pi Day should really be called Pi Approximation Day. The ratio of a circle's circumference to its diameter is commonly shortened to 3.14, but the sequence is actually infinite. Just in time for Pi Day on March 14 (3/14), a Google engineer has set a new record for the most pi digits ever calculated, Business Insider reports.

The previous record for the known digits of pi stood at 22.4 trillion digits. As Google announced on Pi Day 2019, Emma Haruka Iwao, a cloud developer advocate who's been with the company for three years, has added 9 million digits to that figure.

Working out of a lab in Osaka, Japan, she used Google's cloud-computing service to crunch 170 terabytes of data. For comparison, a single terabyte can hold 40 days worth of video. The process required 25 virtual machines running the y-cruncher program over four months.

According to Google, this marks the first time cloud computing has been used to calculate a record number of pi digits. Haruka Iwao has been working on cracking new pi sequences since she first downloaded software to calculate the number on her home computer at age 12. She's the third woman to break the pi record, and she's interested in discovering even more digits.

Anyone can download the full sequence onto their computer from Google. Memorizing all 31,415,926,535,897 digits may be impossible, but you can memorize at least the first 100 with this basic technique.

[h/t Business Insider]

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