Discworld Magic

Magic is the principal force on the Discworld, and operates in a similar vein to elemental forces such as gravity and electromagnetism. The Discworld's "standing magical field" is basically the local breakdown of reality that allows a flat planet on the back of a turtle to even exist. The other varieties of magic are usually methods of shaping this force. It warps reality in much the same way as gravity warps space-time. Areas with larger than normal quantities of background magic tend to display unusual qualities, even for the Discworld . Very high quantities of magic can knock a hole in reality, leading to incursions from the Dungeon Dimensions, or, almost as bad, the world of the Elves. On the Discworld, reality is broken into elementary particulate fragments. These particles are known as "resons" (literally, "thingies") and high amounts of resons reflect a higher fragmentation of "thing-ness" (that is, reality) in the local area.

For special reasons the number eight, the number of the eighth colour and colour of Magic octarine, is extremely magical on the Discworld, and should never, ever, be spoken by a wizard, especially in certain places. Doing so may allow the ancient dungeon dimension creature "Bel-Shamharoth the sender of eight" to break into our dimension.

The Discworld's magical field is centred on Cori Celesti. Everyday natural forces, such as light and magnetism, are muffled by the power of the Discworld's magical field, and rather than a magnetised needle, navigators on the Discworld use a needle of octiron, which will always point towards Cori Celesti, in a compass. Light is so oddly affected by magic that, as it passes into the Discworld's atmosphere, it actually slows down from millions to hundreds of miles an hour, so that, as the Discworld has no horizon, it is actually possible to see days into the past from some of the higher mountain peaks. One odd effect of this is that the Discworld has time zones, when, as a flat world, it shouldn't. Another effect is that, as witnessed by Vimes, the red and blue-shifting of light becomes noticeable when traveling at speeds greater than one hundred and twenty miles per hour.