Sunday, July 29, 2007

Steampunk Science: The Luminiferous Ether, part II

Original diagram of Ether measureing device

There are two different kinds of waves: longitudinal and transverse. Sound is a longitudinal wave: air molecules move forward, bunching up and forming small volume at high pressure, and recoil backward, while the new molecules they pushed moved forward in turn. Each bit of air moves backwards and forward along the direction the sound wave is moving. On the other hand, if a guitar string is plucked, each section of the guitar string moves up and down, at right angles to the length of the string down which the wave travels; that is, the motion of the string is a transverse wave.

Engine room of a Ether-based flyer (ok - another excuse to use a Space 1889 pic - last one, I promise!)

A fluid such as air or water can only carry longitudinal waves. A solid such as steel or diamond can carry both longitudinal and transverse waves. But light is a purely transverse with no longitudinal aspect. So the ether can’t be a gas, or even an ordinary solid, but it is much more rigid than diamond, as diamond is more rigid than water. The high speed of light indicates that the ether has very high stiffness, very low density, or both.

Finally, the ether does not interact with ordinary matter through any sort of mechanical impact; the two pass right through each other. Only electricity charged matter can influence the ether.

Stoddard, W.H. (2000) - Gurps Steampunk, pg. 95, SJG:Austin
[edited for removal of game specific content]

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