Dr. Gordon Emslie: Spinning Pliers, the Chaotic Obliquity of Mars, and the Existence of Extraterrestrial Life

Gordon Emslie, provost and vice president for Academic Affairs and professor of physics and astronomy at Western Kentucky University, gives a lecture, "Spinning Pliers, the Chaotic Obliquity of Mars and the Existence of Extraterrestrial Life." The basic principles of rigid body rotation have been known for over two hundred years; yet the resulting motion is sometimes quite surprising. A movie from a Space Shuttle mission shows this quite vividly: while the rotation of an astronaut is straightforward (like a spinning ice skater), the motion of a set of pliers is quite fascinating and totally unexpected. I will discuss how these surprising motions come about. The rotation of planets offers equally surprising behaviors. As a striking example, the tilt angle of Mars undergoes dramatic transitions, so that the seasonal variation of temperature on the Martian surface is quite different now than in the distant past. Why has the Earth not suffered such dramatic changes in tilt? The surprising answer to this question means that we may have to drastically reduce our estimates for the number of habitable planets in the Galaxy. This perhaps explains why a recently-completed five year search, in ten million radio channels, produced not a single example of a signal from our galaxy that is attributable to extraterrestrial life.

Lai'Anna D Martin

2/28/2014 10:30:00 PM