The Number Phi

1.618

Langdon turned to face his sea of eager students. “Who can tell me what this number is?”

A long-legged math major in back raised his hand, “That’s the number PHI.” He pronounced it fee.

“Nice job Stettner,” Langdon said. “Everyone, meet PHI.”

…
“PHI is generally considered the most beautiful number in the universe.”

As Langdon loaded his slide projector, he explained that the number PHI was derived from the Fibonacci sequence—a progression famous not only because the sum of adjacent terms equaled the next term, but because the quotients of adjacent terms possessed the astonishing property of approaching the number 1.618—PHI!

Despite PHI’s seemingly mystical mathematical origins, Langdon explained, the truly mind-boggling aspect of PHI was its role as a fundamental building lock in nature. Plants, animals, and even human beings all possessed dimensional properties that adhered eerily exactitude to the ratio of PHI to 1.

“PHI’s ubiquity in nature,” Langdon said, killing the lights, “clearly exceeds coincidence, and so the ancients assumed the number PHI must have been preordained with the Creator of the universe."
- Dan Brown. The DaVinci Code. DoubleDay: New York, 2003. pg 93-94

I don't know how much of this is based on fact. A quick Google search on "phi" didn't turn up much. But I really do like this idea. It seems to suggest an order to the universe.

It kind of sounds like the theory of Intelligent Design. Brown has Langdon state a few other natural occurrences of PHI that I will succinctly list here,

1. divide the number of female bees by the number of male bees in any beehive in the world and you always get the same number – PHI
2. nautilus – a cephalopod mollusk that pumps gas into its chambered shell to adjust its buoyancy. The ratio of each spiral’s diameter to the next is PHI
3. Sunflowers grow in spirals and the ratio of each rotations diameter to the next is PHI
4. Human bone structure –distance from tip of head to the floor, then divide that y the distance from your belly button to the floor – PHI
5. Humans cont. – distance from your shoulder to your finger tips, and then divide it by the distance from your elbow to your finger tips – PHI
6. Humans cont. – Hip to floor divided by knee to floor. Finger joints. Toes. Spinal divisions. PHI. PHI. PHI