Pi is Exactly 3
Historically there have been numerous attempts to square a circle, including an attempt in 1894 to pass legislation in the United States that would definitively and erroneously signify Pi as exactly 3.

Schrödinger’s Cat is Dead
Schrödinger’s cat is a thought experiment, sometimes described as a paradox, devised by Austrian physicist Erwin Schrödinger in 1935. The scenario presents a cat which may be simultaneously both alive and dead, as a result of being linked to a random subatomic event that may or may not occur.

Hail Double Knob Children of Mars
In an attempt to share his controversial findings with colleagues while shielding them from the authorities, Galileo developed a code of anagrams. This was sent to Kepler in confidence, unfortunately Kepler was unable to decode the message correctly and created this garbled text.