Why is the pope's cassock white?

Why is it that our pope’s “normal” garments (clothes – I’m sorry, I don’t know the exact English terms) have the color white, while the clothes of many other clergymen are often darker, even black?

The custom of popes wearing white cassocks and clerical garb dates to Pope St. Pius V, a Dominican who chose to continue to wear the Dominican white habit as pope. Successive popes continued the custom until it became the traditional color of the pope’s clothing.

DISCLAIMER: The views and opinions expressed in these forums do not necessarily reflect those of Catholic Answers. For official apologetics resources please visit www.catholic.com.