Those numbers people sure are fun. Mainly science nerds and math geeks, they’ve designated a bunch of calendar dates as days to celebrate math, science, and the historic figures who advanced our state of numeric-based knowledge. Remember Mole Day from last month? Or Pi Day from last year?

This month (*today actually, 11/23*) we recognize Fibonacci Day to celebrate the famous sequence of numbers and to honor Leonardo of Pisa, also known as Leonardo Bonacci (born circa A.D. 1170). Better known today as Fibonacci, the famous nickname (which loosely translates as “son of the Bonacci clan”) was bequeathed upon him in the nineteenth century by scholars who wanted to differentiate him from another well-known Leonardo of Pisa.

Fibonacci is most famous for the Fibonacci series (also called the Fibonacci sequence). He did NOT discover the sequence, despite what many sources say. No, the Fibonacci series was in use in India for centuries before Leonardo included it in a popular European math text for merchants.

The series goes like this (note that the sequence does not have to begin with zero – it can start with 1, 1, … – the results are the same):

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, …

The first two numbers of the series are given as 0 and 1. To find the next number in the series, add the first two numbers together:

0+1=1 and the series becomes 0, 1, 1, …

To find the next number in the series, add together the most recent pair of numbers found:

1+1=2 which yields 0, 1, 1, 2, …

1+2=3 and we have 0, 1, 1, 2, 3, …

2+3=5 resulting in 0, 1, 1, 2, 3, 5, …

3+5=8 …and so on. See the pattern? The next number in the sequence is always the sum of the previous two numbers.

A common way to graph the Fibonacci series looks like this:

From this arrangement, Fibonacci’s Spiral can be drawn. This curve is said to resemble many objects in nature.

Other objects that are widely, but falsely, believed to conform to Fibonacci’s Spiral include the nautilus shell, spiral galaxies, hurricanes, some plants such as certain aloe species.

The golden ratio is derived from the Fibonacci sequence and, popularly but once again falsely, believed to be a mathematical key to beauty. As such, human proportions (including Leonardo da Vinci’s drawing, “Vitruvian Man”) and architecture (the Parthenon, the Pyramid at Giza, and Renaissance designs) have all been incorrectly attributed to the golden ratio.

The Fibonacci Series does have valid applications in economics, computational analysis, science, and mathematics, but most humans aren’t really interested in any of that because it’s not easy to apply simple visual concepts like the Fibonacci spiral or the golden ratio.

I’m certain you’ve been holding your breath in complete suspense this entire time, so I’ll point this out now – today (11/23) was chosen to observe Fibonacci Day because the start of the sequence (1, 1, 2, 3, …) most closely represents today’s date. I know, you’re in awe.

Happy Fibonacci Day!

**Question of the Night:** Do you really dig math, or do you just want to bury it?