If you experience any technical difficulties with this video or would like to make an accessibility-related request, please send a message to [email protected]. For more information, see this video: http://www.youtube.com/watch?v=Ja886GtHlcE University of Chicago physicists have succeeded in creating a vortex knot—a feat akin to tying a smoke ring into a knot. Linked and knotted vortex loops have existed in theory for more than a century, but creating them in the laboratory had previously eluded scientists.