One example is the Madhava series, which says π=4(1-1/3+1/5-1/7+1/9…), but it takes a lot of terms to produce correct decimal values. Techniques changed dramatically after the 17th century, with the development of calculus and infinite series, and processes were discovered that could get closer and closer to the true value of pi. It has been suggested that the ancient Egyptians used 22/7, while Archimedes used geometry to prove that 223/71< π<22/7 in the 3rd century BCE. Babylonian mathematics usually set pi as 3, which was sufficient for the architectural projects of the time, although one tablet from the time offered a value of 25/8. And, of course, there’s its links with circles – pi is the ratio of a circle’s circumference to its diameter, and that fact enables us to calculate the circumference of some incredibly large bodies, from the Earth and the Milky Way to the observable universe.Īs a result, scientists throughout history have approximated and found closer values of pi. It is also something known as a transcendental number, meaning it cannot be defined through any simple equation featuring whole numbers, something known as early as 1768. If you wanted to express a number like 1/7 decimally, you could write 0.1428571428571… and so on, but that’s not possible with pi. What makes pi special? It’s an irrational number, meaning that it needs infinitely many decimals to express it, but it’s also an irrational number with no repeating patterns. The digits may not be scientifically useful, but there are lots of reasons that mathematicians and computer scientists are awaiting the details of this calculation. Given that we only need 65 decimal places to know the size of the observable universe to within a Planck length (the shortest possible measurable distance), one question to ask is why bother at all. The previous world record pi calculation achieved 50 trillion digits, but now a team of Swiss researchers have claimed a new world record for calculating the digits of pi – an incredible 62.8 trillion figures. But it’s hard to conceptualise just how long the number is. P i ( π) is a number that everyone is broadly familiar with – if you did maths at school, no doubt the value of 3.14 was drilled into you.