After Heaviside’s attempts to generalize Maxwell’s equations, Heaviside came to the conclusion that electromagnetic waves were not to be found as longitudinal waves in “free space” or homogeneous media. But Maxwell’s equations do lead to the appearance of longitudinal waves under some circumstances, for example, in plasma waves or guided waves. Basically distinct from the “free-space” waves, such as those studied by Hertz in his UHF experiments, are Zenneck waves. The longitudinal modes of a resonant cavity are the particular standing wave patterns formed by waves confined in a cavity. The longitudinal modes correspond to those wavelengths of the wave which are reinforced by constructive interference after many reflections from the cavity’s reflecting surfaces. Recently, Haifeng Wang et al. proposed a method that can generate a longitudinal electromagnetic (light) wave in free space, and this wave can propagate without divergence for a few wavelengths.
For all its romance inspiring awesomeness, the moon has another side to its personality. Werewolves, mood swings and even wild behavior are often blamed on the full moon. How many times have you heard the question acrimoniously asked, "is it a full moon tonight?"
It is not a very expensive stone and is made into necklaces or bigger pieces for jewelry purposes. I especially like the deep, dark blue version with golden pyrite sprinkles creating very unique patterns mined only in Afghanistan. The lighter blue, grayish variety is found in Chile.
"There's an assumption we do have to make, which is that there's no changes in the material itself, and that all of the bumps we're seeing (in the gravity field) are from changes in the porosity and the amount of air between the rocks," Dr. Soderblom continued to explain in the September 10, 2015 MIT Press Release.