Advances | Technology See Inside Traveling Salesman: A Seemingly Unsolvable Problem Offers a Glimpse of the Limits of Computation A seemingly unsolvable problem offers a glimpse at the limits of computation By William J. Cook | May 18, 2012 Image: Illustration by Thomas Fuchs Is it hopeless to try to compute the shortest route to visit a large number of cities? Not just a good route but the guaranteed shortest. The task is the long-standing challenge known as the traveling salesman problem, or TSP for short. Finding a method that can quickly solve every example of the TSP would be a stunning breakthrough in mathematics. Using complexity theory, such a method would allow us to solve efficiently any computational problem for which answers can be ... Continue reading →

Love Code: A twist of light only mantis shrimp can see By Davide Castelvecchi From Science News, March 22nd, 2008; Vol.173 #12 (p. 179) For love, some would twist the laws of physics. Short of doing that, mantis shrimp communicate with the other sex by spinning light waves, biologists find. The feat seems to be unique to this animal. Light is made of electromagnetic waves. These are electric and magnetic fields that wiggle perpendicular to each other and to a light ray’s direction. Many invertebrates have sophisticated eyes that can detect wavelengths of light invisible to humans. Some, including bees, can also distinguish linearly polarized light. That’s when a light ray’s electric field wiggles not in varying directions, but rather in one precise direction that ... Continue reading →

David Bowser for the Texas Tribune A plant that produces roughly 30 percent of the planet’s helium rises from the prairie about 20 miles northwest of Amarillo. At Wally’s Party Factory, a 32-store chain based in the North Texas town of Ennis, balloons no longer contain 100 percent helium — the total is down to 60 percent — and an additive is pumped in to help certain types float better. Expanded coverage of Texas is produced by The Texas Tribune, a nonprofit news organization. To join the conversation about this article, go to texastribune.org. David Bowser for the Texas Tribune A weather vane at the plant. The space shuttle program, which ended last summer, was a major user of helium produced here. “We’re doing a ... Continue reading →

Bertrand Arthur William Russell Born: 18 May 1872 in Ravenscroft, Trelleck, Monmouthshire, Wales Died: 2 Feb 1970 in Penrhyndeudraeth, Merioneth, Wales Click the picture aboveto see eight larger pictures Show birthplace location Bertrand Russell published a large number of books on logic, the theory of knowledge, and many other topics. He is one of the most important logicians of the 20th Century. Russell's Mathematical Contributions Over a long and varied career, Bertrand Russell made ground-breaking contributions to the foundations of mathematics and to the development of contemporary formal logic, as well as to analytic philosophy. His contributions relating to mathematics include his discovery of Russell's paradox, his defence of logicism (the view that mathematics is, in some significant sense, reducible to formal logic), his introduction ... Continue reading →