Why Mathematicians Can’t Find the Hay in a Haystack. Kevin Hartnett. www.quantamagazine.org . Sep 17, 2018. Irrational numbers occupy most of the number line. If you were to pick a number on the number line at random, there is literally a 100% chance that it will be irrational (probabilities with inifinities are spooky). Yet, we almost never encounter irrational numbers for we can’t write them down....