(Gravity puts its pants on one leg at a time just like everyone else.) NerdNiteChicago2011October Thursday, October 20th, 201
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The Ghost of Ted Fujita!–Mike Renkosiak When Skilling gets giddy predicting nasty weather, do you feel his excitement? Does distant thunder draw your eyes skyward? Do you set your DVR for the Discovery Channel on Sunday nights at 9? If any of these things describe you or if you wonder why there are now so many weather weenies out there, come check out the world of storm chasing. Mike Renkosiak is a member of Chicago’s Community Emergency Response Team and a meteorological hobbyist. His interest in weather goes back almost 40 years when a funnel cloud chased his family from a picnic. Then there was the science fair project on devising homemade weather instruments using simple things like empty white gas cans, conduit, and hair (which he wishes he had back) When it was a first place winner he knew he was on to something. Now a professional and a seasoned storm chaser, you can follow him @WindyCityWxMan. Hot Rocks: Naturally Occurring Nuclear Piles–Bo Jayatilaka The first artificial nuclear reactor, Chicago Pile-1, was constructed at the University of Chicago, by a team led by Enrico Fermi, in late 1942. The first sustained nuclear fission chain reaction on Earth was about 1.7 billion years ago, in what is now the nation of Gabon. Neutron-multiplying critical masses of Uranium-235 catalyzing their own nuclear fission? Yep, nature had already thought of that one. (Suck it, Leó Szilárd.) Bo Jayatilaka is not the kind of doctor who can fix broken bones, he’s the other kind. The science kind. Warped Space-Time and Pants–Jim Pivarski Years before I studied it in college and grad school, General Relativity was high on the list of things that I had to know about before I die. Somehow, space and time are curved, which just sounds trippy and seems to open the door to wormholes and warp drive. I got a working understanding of it from three semesters of classwork, but I didn’t really have the “Aha!” moment until I learned to sew. Sewing (as well as knitting/crocheting) demands an intuitive understanding of intrinsic curvature; it should be a prerequisite for Riemannian Geometry 101. This talk addresses the question, “What does it mean to say that space-time is curved?” I’ll present the picture that I wish I had in mind before learning the subject formally. We’ll use hand-sewn cloth models of space-time manifolds to help us visualize how curvature and gravitation are related, as well as some morphologically correct pictures of the time-evolution of the universe. Jim Pivarski is sometimes a particle physicist at Fermilab, sometimes a statistical programmer, and sometimes a science writer for Fermilab Today and his own website, Coffeeshop Physics. Be there AND be square!
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In addition, time and space dimensions should not be viewed as exactly equivalent in Minkowski space-time. One can freely move in space but not in time. Thus, time and space coordinates are treated differently both in special relativity (where time is sometimes considered an imaginary coordinate) and in general relativity (where different signs are assigned to time and space components of spacetime metric ).