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What Does the Fourth Dimension Actually Look Like?
Reporting by Quanta MagazineRead the original at quantamagazine.org
Executive Summary
Facts Only
* Topology is the study of abstract spaces.
* Topology differs from geometry as it focuses on global connectedness rather than measurement.
* The Möbius strip demonstrates a topological property: cutting the strip does not separate it.
* Maggie Miller researches knots, surfaces, and four-dimensional spaces at the University of Texas at Austin.
* Three-dimensional space is defined by three perpendicular directions (forward, backward, left, right, up, down).
* Topologists do not have a notion of distance, focusing instead on whether spaces are continuously deformable into one another.
* The statement "two plus two equals four" is related to the failure of intuition when moving from three to four dimensions regarding certain topological theorems.
* Knots in three dimensions can be understood via Dehn surgery on knots within the 3-sphere, which can generate more complicated spaces.
* In four dimensions, knotted loops become trivial (all the same) because there is one extra dimension of freedom.
* Seifert surfaces are surfaces that live within three-dimensional space and have a boundary, which is a knot.
Full Take
From the original · Quanta Magazine
Introduction We know all about how things exist in the three dimensions of length, width, and height. Physicists often talk about time as a fourth dimension, but what if there were a fourth spatial dimension — another direction entirely?Read the full story at quantamagazine.org
