Phi: The Golden Ratio
Reference Article: Facts about phi, the golden ratio.
The number phi, often known as the golden ratio, is a mathematical concept that people have known about since the time of the ancient Greeks. It is an irrational number like pi and e, meaning that its terms go on forever after the decimal point without repeating.
Over the centuries, a great deal of lore has built up around phi, such as the idea that it represents perfect beauty or is uniquely found throughout nature. But much of that has no basis in reality.
Definition of phi
Phi can be defined by taking a stick and breaking it into two portions. If the ratio between these two portions is the same as the ratio between the overall stick and the larger segment, the portions are said to be in the golden ratio. This was first described by the Greek mathematician Euclid, though he called it "the division in extreme and mean ratio," according to mathematician George Markowsky of the University of Maine.
You can also think of phi as a number that can be squared by adding one to that number itself, according to an explainer from mathematician Ron Knott at the University of Surrey in the U.K. So, phi can be expressed this way:
phi^2 = phi + 1
This representation can be rearranged into a quadratic equation with two solutions, (1 + √5)/2 and (1  √5)/2. The first solution yields the positive irrational number 1.6180339887… (the dots mean the numbers continue forever) and this is generally what's known as phi. The negative solution is 0.6180339887... (notice how the numbers after the decimal point are the same) and is sometimes known as little phi.
One final and rather elegant way to represent phi is as follows:
5 ^ 0.5 * 0.5 + 0.5
This is five raised to the onehalf power, times onehalf, plus onehalf.
Related: The 11 Most Beautiful Mathematical Equations
Phi is closely associated with the Fibonacci sequence, in which every subsequent number in the sequence is found by adding together the two preceding numbers. This sequence goes 0, 1, 1, 2, 3, 5, 8, 13, 21, 34 and so on. It is also associated with many misconceptions.
By taking the ratio of successive Fibonacci numbers, you can get closer and closer to phi. Interestingly, if you extend the Fibonacci sequence backward — that is, before the zero and into negative numbers — the ratio of those numbers will get you closer and closer to the negative solution, little phi −0.6180339887…
Does the golden ratio exist in nature?
Though people have known about phi for a long time, it gained much of its notoriety only in recent centuries. Italian Renaissance mathematician Luca Pacioli wrote a book called "De Divina Proportione" ("The Divine Proportion") in 1509 that discussed and popularized phi, according to Knott.
Pacioli used drawings made by Leonardo da Vinci that incorporated phi, and it is possible that da Vinci was the first to call it the "sectio aurea" (Latin for the "golden section"). It wasn't until the 1800s that American mathematician Mark Barr used the Greek letter Φ (phi) to represent this number.
As evidenced by the other names for the number, such as the divine proportion and golden section, many wondrous properties have been attributed to phi. Novelist Dan Brown included a long passage in his bestselling book "The Da Vinci Code" (Doubleday, 2000), in which the main character discusses how phi represents the ideal of beauty and can be found throughout history. More sober scholars routinely debunk such assertions.
For instance, phi enthusiasts often mention that certain measurements of the Great Pyramid of Giza, such as the length of its base and/or its height, are in the golden ratio. Others claim that the Greeks used phi in designing the Parthenon or in their beautiful statuary.
But as Markowsky pointed out in his 1992 paper in the College Mathematics Journal, titled "Misconceptions About the Golden Ratio": "measurements of real objects can only be approximations. Surfaces of real objects are never perfectly flat." He went on to write that inaccuracies in the precision of measurements lead to greater inaccuracies when those measurements are put into ratios, so claims about ancient buildings or art conforming to phi should be taken with a heavy grain of salt.
The dimensions of architectural masterpieces are often said to be close to phi, but as Markowsky discussed, sometimes this means that people simply look for a ratio that yields 1.6 and call that phi. Finding two segments whose ratio is 1.6 is not particularly difficult. Where one chooses to measure from can be arbitrary and adjusted if necessary to get the values closer to phi.
Attempts to find phi in the human body also succumb to similar fallacies. A recent study claimed to find the golden ratio in different proportions of the human skull. But as Dale Ritter, the lead human anatomy instructor for Alpert Medical School (AMS) at Brown University in Rhode Island, told Live Science:
"I believe the overarching problem with this paper is that there is very little (perhaps no) science in it … with so many bones and so many points of interest on those bones, I'd imagine there would be at least a few" golden ratios elsewhere in the human skeletal system.
Related: Photos: Large Numbers That Define the Universe
And while phi is said to be common in nature, its significance is overblown. Flower petals often come in Fibonacci numbers, such as five or eight, and pine cones grow their seeds outward in spirals of Fibonacci numbers. But there are just as many plants that don't follow this rule as those that do, Keith Devlin, a mathematician at Stanford University, told Live Science.
People have claimed that seashells, such as those of the nautilus, exhibit properties in which phi lurks. But as Devlin points out on his website, "the nautilus does grow its shell in a fashion that follows a logarithmic spiral, i.e., spiral that turns by a constant angle along its entire length, making it everywhere selfsimilar. But that constant angle is not the golden ratio. Pity, I know, but there it is."
While phi is certainly an interesting mathematical idea, it is we humans who assign importance to things we find in the universe. An advocate looking through phicolored glasses might see the golden ratio everywhere. But it's always useful to step outside a particular perspective and ask whether the world truly conforms to our limited understanding of it.
Additional resources:
 Here's a helpful explainer video on the golden ratio from Tipping Point Math.
 Read more about the myth behind the golden ratio in nature from GoldenNumber.net.
 Watch the Khan Academy's explanation of the golden ratio.
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Adam Mann is a freelance journalist with over a decade of experience, specializing in astronomy and physics stories. He has a bachelor's degree in astrophysics from UC Berkeley. His work has appeared in the New Yorker, New York Times, National Geographic, Wall Street Journal, Wired, Nature, Science, and many other places. He lives in Oakland, California, where he enjoys riding his bike.

jeanna Many people still think the golden ratio is found all over nature and represents perfect beauty  that is a myth. Even so, phi is a pretty cool math concept. For instance, it's related to the Fibonacci sequence: If you take the ratio of successive Fibonacci numbers, you get closer and closer to phi.Reply
Also, like Pi, the golden ratio is irrational and goes on forever! 
Reeii Education The Golden Ratio, also called Divyank Ratio, is the most economical algorithm of Nature with which the perfect and most beautiful objects of the universe and Nature are designed.Reply
It is designated as Phi.
To comprehend the fundamental of the Divyank Ratio, let us contemplate on the following.
Fibonacci sequence:
It is represented as, 1123581321345589144 and so forth.
It is primarily observed in the plant kingdom, like, the branches of a tree, the arrangement of leaves, flowers, fruits, seeds of pineapples, and the pine cone etc. It is also observed in the family tree of honeybees and rabbits etc.
In reality, the Golden Ratio is seen between the tenth and eleventh sequence (89/55=1.618...) of Fibonacci sequence.
The Golden Ratio:
It is a linear number and represents the two dimensions of an object.
It is also an irrational number with neverending infinite numbers of digits, 1.618033988749895..., which are highly confusing and misleading.
It is calculated with the help of the following manmade mathematical formula.
½+√5/2=1.618033988749895…
The universe may be infinite but every object of Nature is limited.
Hence, there should be limited numbers of digits.
This confusion is resolved by Divyank Ratio of 1:1.618034.
Divyank Ratio: 1:1.618034.
It represents the most approximate decimal value of the Golden Ratio.
According to Akhand Sutra, every object of Nature is represented with two complementary and inseparable components, the central core (Shakta) and the dynamic force (Shakti).
The exact value of Shakta is 38.1966% and the precise value of Shakti is 61.8034%.
The Real Beauty of Divyank Ratio:
The square of 61.8034 is equal to 3819.66 (a hundred times the value of Shakta).
Such a precise representation is not seen in the known Golden Ratio.
Divyank Sequence:
It is represented by 61.8034, 100.00, 161.8034, 261.8034 and so forth.
Divyank Sequence is much better than the Fibonacci sequence or the Golden Ratio.
Now, let us raise another question.
What is the Ultimate Divine Design of Creation of Objects of Nature?
The answer to this natural question is not found in the available literature.
It is established that every object of Nature is formed in three critical stages, namely, the first stage of creation, the second stage of development, and the third stage of maturation.
What are the exact values of three stages of formation of the Golden Ratio?
The world is not aware of the answer.
The ultimate divine design is called Divyank, the Divine Constant.
Divyank reveals the exact mathematical values of the three critical stages of formation of objects of the universe and Nature, namely, the first stage of creation, the second stage of development, and the third stage of maturation.
Divyank is represented as ((22/21)10.34419) = 1.618034.
The number, 22/21 represents the first stage of creation.
The number 10 represents the ten stages of development.
The five digits, 0.34419, represent the last stage of maturation.
The sum, 1.618034 represents the most approximate decimal value of the Golden Ratio, the most economical algorithm of Nature.
Divyank can be called The Mother of the Golden Ratio.The Scientific Proof of Divyank:
1. The Formation of Red Blood Cells: The irregular and spherical pluripotent hemopoietic stem cells, which lead to the production of mature red blood cells, are 21 microns in size and have a volume of 900 cubic microns. The size increases to 22 microns and then goes through ten stages of development to become a concavely shaped cell in 21 days and the volume reduces to 90 cubic microns.
2. The Perfect Double Helix: The length of Double Helix is 21 Angstrom. Each spiral is 22 Angstrom and there are 10.34419 strands. The length and breadth are in the ratio of 38.1966% and 61.8034%.
Is the above knowledge a mere coincidence?
The Scientific Applications of Divyank Ratio:
1. With the absolute values of Divyank Ratio, we can easily calculate the single and most reliable value of every vital biophysical parameter of the perfect adult human anatomy, physiology, and biochemistry etc.
2. If we can maintain these values for life, we can curtail aging, prevent the most common ailments, and make optimum of the human birth, life, brain, mind, consciousness, and potentials etc.
3. With the help of Divyank, Divyank Ratio, and Divyank Sequence, we can eliminate the confusion created by the wide spectrum of values of different aspects of biophysical parameters of the body.
4. With that, we can simplify medical education, research, and treatment modules.
5. Only perfectly healthy, wealthy, wise, and happy human beings and human society can create harmony, equilibrium, and peace in the world, the urgent need of the day. 
RachelRA Reeii Education said:This confusion is resolved by Divyank Ratio of 1:1.618034.
Divyank Ratio: 1:1.618034.
It represents the most approximate decimal value of the Golden Ratio.
According to Akhand Sutra, every object of Nature is represented with two complementary and inseparable components, the central core (Shakta) and the dynamic force (Shakti).
The exact value of Shakta is 38.1966% and the precise value of Shakti is 61.8034%.
The Real Beauty of Divyank Ratio:
The square of 61.8034 is equal to 3819.66 (a hundred times the value of Shakta).
Such a precise representation is not seen in the known Golden Ratio.
Divyank Sequence:
It is represented by 61.8034, 100.00, 161.8034, 261.8034 and so forth.
Divyank is represented as ((22/21)10.34419) = 1.618034.
The number, 22/21 represents the first stage of creation.
The number 10 represents the ten stages of development.
The five digits, 0.34419, represent the last stage of maturation.
The sum, 1.618034 represents the most approximate decimal value of the Golden Ratio, the most economical algorithm of Nature.
Divyank can be called The Mother of the Golden Ratio.The Scientific Proof of Divyank:
1. The Formation of Red Blood Cells: The irregular and spherical pluripotent hemopoietic stem cells, which lead to the production of mature red blood cells, are 21 microns in size and have a volume of 900 cubic microns. The size increases to 22 microns and then goes through ten stages of development to become a concavely shaped cell in 21 days and the volume reduces to 90 cubic microns.
2. The Perfect Double Helix: The length of Double Helix is 21 Angstrom. Each spiral is 22 Angstrom and there are 10.34419 strands. The length and breadth are in the ratio of 38.1966% and 61.8034%.
Is the above knowledge a mere coincidence?
The Scientific Applications of Divyank Ratio:
1. With the absolute values of Divyank Ratio, we can easily calculate the single and most reliable value of every vital biophysical parameter of the perfect adult human anatomy, physiology, and biochemistry etc.
2. If we can maintain these values for life, we can curtail aging, prevent the most common ailments, and make optimum of the human birth, life, brain, mind, consciousness, and potentials etc.
3. With the help of Divyank, Divyank Ratio, and Divyank Sequence, we can eliminate the confusion created by the wide spectrum of values of different aspects of biophysical parameters of the body.
4. With that, we can simplify medical education, research, and treatment modules.
5. Only perfectly healthy, wealthy, wise, and happy human beings and human society can create harmony, equilibrium, and peace in the world, the urgent need of the day.
Why?
>According to Akhand Sutra, every object of Nature is represented with two complementary and inseparable components, the central >core (Shakta) and the dynamic force (Shakti).
>The exact value of Shakta is 38.1966% and the precise value of Shakti is 61.8034%.
This is where the problem lies. What is the shakta and the shakti? Where do these values come from? Also, you can completely skip half of those steps. 61.8034 over 38.1966 IS 1.6180340659; how you arrived at ((22/21)10.34419) is just needless fantasy. It doesn't even make sense as I am trying to understand it. How do you conclude the 1.61 value from that? It is a division followed by a product; the answer is 1.0476190476.
Yes, frankly, it is a coincidence. More than that, it's just doing maths for fun. In fact, I looked at this post at 6:38AM my time. 61.8034 contains the numbers 6, 3, and 8. Remove the other numbers and separate them and you have 638 and 140. The ratio of those two numbers is 4.5571428571
If you then divide that by the number of potential deities within Christianity (3, give or take 2), you get 1.519047619.
Its sqrt is 2.1347465557
1.6180340659
1.519047619
1.0476190476 (i guess this repeats?). the 047619 repeats forever; so naturally, this makes it a rational number, I'm afraid.
the numbers I made up are better. because i said so.
if we all accept my numbers then we can solve causality and also find me a 6800xt 
Randy Evangelista The Golden Ratio is insignificant on its own. Why is it common in nature? Now that’s a more interesting question. It cannot be denied that the Golden Ratio is observed in nature but for some reason, it is difficult to comprehend its importance. It’s like the air that we breathe, we know it’s there because it's keeping us alive, otherwise, we will be in a different place, but we cannot see or touch it.Reply
We use patterns to describe nature and if we look hard enough, we can even create a mathematical equation for the pattern. This does not mean that the pattern follows the equation. It’s the other way around, the equation follows the pattern.
Keep in mind that the equations we use to describe the patterns are mental constructs, it’s all in our mind. We create these mental constructs to make sense of what we see. Nature can work fine without the equations.
Below link is an example of the Golden Ratio as part of an equation that describes the rotation and arrangement of planets.
Liber Abaci Revisited (1202  2021)