Topic: What makes the Earth quiver? Ringing Earth's bell: what makes our planet constantly quiver? Science News, July 4, 1998 by Richard Monastersky
Fingernails on a chalkboard. Only half joking. I'm actually surprised to find out this is a surprise. Doesn't everything have a resonant frequency at which it vibrates when stimulated?
I'm with One Raven on this. I'm more surprised that this discovery came as a surprise, then I am at the discovery itself.
Yes and no. There's this little thing called damping, and since the Earth is not a perfect solid, oscillations will and do damp out. The discovery was deemed important enough to be published in Science, and explanations were deemed important enough to be published in Nature and in other prominent journals. Kurrle, D., and R. Widmer-Schnidrig (2006), "Spatiotemporal features of the Earth's background oscillations observed in central Europe", Geophys. Res. Lett., 33, L24304, doi:10.1029/2006GL028429. We find clear seasonal variations in the direction of propagation and a striking rate of recurrence in these seasonal patterns. This seasonality provides evidence of an excitation of the background oscillations by large-scale atmospheric and/or oceanic processes which confirms previous studies. Those previous studies: Rhie, J., and B. Romanowicz (2004), "Excitation of earth's incessant free oscillations by atmosphere-ocean-seafloor coupling", Nature, 431, 552-556. 2004. Fukao, Y., K. Nishida, N. Suda, K. Nawa, and N. Kobayashi (2002), "A theory of the Earth's background free oscillations", J. Geophys. Res., 107(B9), 2206, doi:10.1029/2001JB000153. Kobayashi, N., and N. Nishida, "Continuous excitation of planetary free oscillations by atmospheric disturbances", Nature, 395, 357-360, 1998. In short, the mysterious hum is not evidence of an expanding Earth.
As soon as I read the title, I put into google "Gaia's vibrator". Here is the best result: http://en.wikipedia.org/wiki/Image:Chicago_Spire.jpg Although it is only a project, and in fact is unlikely to be built.
I thought anyone who was innovative enough to think up that phrase didn't deserve to be the person who had apparently put this thread to sleep. Please Register or Log in to view the hidden image!