Friday, December 5, 2008

Anniversary: Uncertainty

Werner Heisenberg was born on this day in 1901. Heisenberg is a giant of theoretical physics - he helped establish quantum mechanics and is best known for his uncertainty principle. Uncertainty asserts that you cannot precisely know both the momentum and position of a particle. Measuring one variable will change the other. Against our intuition, the universe is fundamentally uncertain. Hazy probabilities underlie everything. In fact, there's an exceedingly remote, but nonzero, chance that you can walk straight through a wall like a superhero. You'll never actually do it, but it's nice to think you might.

(image credit: Heisenberg circa 1926, Fritz Hund, The Niels Bohr Archives,