Pi is a unique number that is the ratio of the circumference of a circle to its diameter. Since this number is irrational, it cannot be written down. Instead, it is infinitely long, with a series of non-repeating numbers, of which mathematicians number in the trillions.
But how exactly was this irrational number discovered? And after a huge number of scientists have spent thousands of years studying pi, does this number still have any secrets and secrets? From the ancient origins of number to its unexplored future, here are some of the most surprising facts about pi.
How to remember pi?
The record for the largest decimal representation of pi, memorized by heart, belongs to Indian citizen Rajvir Vellore, who recited 70 thousand decimal places of pi from memory on March 21, 2015. His achievement is noted in the Guinness Book of Records.
Previously, the record was held by Chao Lu from China, who learned a little less than decimal values and recited 67,890 digits from memory in 2005, according to the same book.
Promotional video:
The unofficial record holder is Akira Haragachi, who videotaped the listing of one hundred thousand decimal places of pi in 2005, and later increased that number to 117 thousand decimal places, according to The Guardian.
Pi enthusiasts and lovers are learning more and more decimal places. To do this, many people use memory enhancers and mnemonic tricks such as pyphylology. They often use verses in which the number of letters in each word corresponds to the digit in the decimal value pi.
There is a special pi language
A couple more words about that same "pyphylology": lovers of literature and mathematics invented a dialect known as Pilish, in which the number of letters in successive words corresponds to the digits of the decimal values of pi. For example, Mike Keith has written an entire book in this mathematical-literary dialect.
Pi increase
Since pi is an infinite irrational number, people are unlikely to ever be able to determine absolutely all decimal values of pi. However, the number of decimal places calculated for pi has grown significantly since its first use. The Babylonians thought the values 3 and 1/8 were sufficient for use four thousand years ago. In ancient China, they were content with using the whole number 3. But by 1665 Sir Isaac Newton had calculated 16 decimal places for pi. By 1719, the French mathematician Thomas Fante de Lani had calculated 127 decimal places.
The development of computers has greatly improved people's knowledge of pi. Between 1949 and 1967, the number of known decimal places for pi skyrocketed from 2,000 to 500,000. Late last year, Peter Trub, a scientist at the Swiss company Dectris Ltd., used a multi-threaded computer program to calculate the 22,459,157,718,361 digits of pi in 105 days.
It is noteworthy that no one needs such a long number of pi. Even if we assume that our universe is a sphere, scientists would need no more than 39 decimal values of pi to calculate its volume.
Even the most accurate calculations of cosmologists and space engineers use no more than 15 decimal values of pi. According to experts, there are no realistic physical calculations that require a more accurate, and therefore long, value of pi.
Pi can be calculated using the old method
If you want to calculate pi literally by hand using the old-fashioned technique, you need a ruler, jar and thread, or a protractor and pencil. It is important that the jar is perfectly round, and you would be good at wrapping the thread around this very circle.
You can also draw a circle with a protractor and then measure its diameter or radius with a ruler.
A more accurate method involves using geometry. Break the circle into multiple segments (imagine a pizza cut into eight or ten slices). Then calculate the length of a straight line that would make the segment an isosceles triangle with two sides of equal length. Adding all the sides of such a triangle results in the approximate value of pi.
Opening pi
Numerous ancient cultures known for their scientific achievements knew about pi. The ancient Babylonians knew about the existence of pi almost 4 thousand years ago. The Babylonians calculated an approximate pi value of 3.125. Egyptian mathematical papyrus dating from 1650 BC e., that is, the most famous Egyptian mathematical document, states that pi is 3.1605. The King James Bible gives the approximate value of pi in cubits, that is, in an archaic unit of length corresponding to the length of the forearm from the elbow to the tip of the middle finger (approximately 46 centimeters). The Greek mathematician Archimedes (287-212 BC) calculated pi using the Pythagorean theorem.
Name
Before the association of this number with the symbol "pi", its name was practically unpronounceable. From the Latin language, the name of the number was translated as "a number that, when multiplied by the diameter, leads to the length of a circle."
The irrational number skyrocketed to fame when the Swiss mathematician Leonhard Euler used it in 1737 in his research on trigonometry. But the famous name of the number did not come from Euler. Pi as such was first mentioned in a book by a lesser known mathematician, William Jones, who used it in 1706 in his book. Jones probably used the pi symbol to denote the periphery of the circle.
Normal number?
Pi is definitely an unusual number, but the question is, is it normal? Although mathematicians have successfully solved many of the mysteries of this irrational number, there are still some unanswered questions.
Mathematicians still don't know if pi is a so-called normal number, since it is infinite. At least based on the first 2.24 trillion digits, pi can be considered a normal number. Of course, given that pi has an infinite number of digits, it is almost impossible to prove this for sure.
Downgrade pi
While mathematicians around the world are fascinated by the number pi, the resistance movement is growing in popularity every year. Some argue that it's time to stop using pi altogether, and not because it is inaccurate, but because it is inconvenient. The tau number (twice pi), for example, is a more intuitive and simpler mathematical constant and an irrational number.
It directly relates a circle to its radius, rather than its diameter, like pi, and works better in trigonometric calculations. According to many scientists, the circle is precisely defined by the radius, not the diameter.
Pi is a very long number
And in the most literal sense of the word. If it was possible to print pi down to the billionth decimal place using the usual 12th font, the sheet would come out two thousand kilometers long. This number would stretch from Moscow to Yekaterinburg.
Marathon pi
In countries with the English system of measures, fans of the number celebrate Pi Day, which falls on March 14 (3/14) with a five-kilometer run. The fact is that five kilometers is a convenient number that is easy to remember, plus, converting it to miles, you can get the number closest to pi (3.10686 miles, to be exact).
Birthday cake
It is already a long tradition among mathematicians around the world: there is a pie on Pi Day. It can be any kind of pie: sweet, meat or even pizza. The main thing is the form. The pi-horn must be round!
Hope Chikanchi