- On the dimensionality of spacetime (space.mit.edu)
Some superstring theories have more than one effective low-energy limit corresponding to classical spacetimes with different dimensionalities. We argue that all but the (3 + 1)-dimensional one might correspond to ‘dead worlds’, devoid of observers, in which case all such ensemble theories would actually predict that we should find ourselves inhabiting a (3 + 1)-dimensional spacetime. With more or less than one time dimension, the partial differential equations of nature would lack the hyperbolicity property that enables observers to make predictions. In a space with more than three dimensions, there can be no traditional atoms and perhaps no stable structures. A space with less than three dimensions allows no gravitational force and may be too simple and barren to contain observers.
- Three Fingers (Washington) (Wikipedia)
The Three Fingers is a mountain which is located in Snohomish County, Washington. At a height of 6,859 feet (2,091 m), it is the 12th most prominent peak of the state, and is also part of the Cascade Range.“Three Fingers” refers to the mountain’s three summits. The Three Fingers is a prominent and recognizable landmark in northern Snohomish County.