Slashdot Mirror
Earth's Constant Hum Explained
MattSparkes writes "It has been known for some time that there is a constant hum that emanates from the Earth, which can be heard near 10 millihertz on a seismometer. The problem was that nobody knew what caused it. It has now been shown that it is caused by waves on the bottom of the sea, and more specifically 'by the combination of two waves of the same frequency travelling in opposite directions.'"
I had a constant 50Hz hum emanating from my loudspeakers once. Swapped the brown and blue wires going to the turntable and that cured it. Reckon somebody at the factory didn't understand that the live wire should be on the INSIDE of a motor stator or transformer whenever there is sensitive electronic equipment nearby. Of course, on the Continent, they could just reverse the plug in the socket with the same effect. What's worse is I've known someone wire a high-impedance (50K ohm) mic to a preamp with about five metres of unshielded cable, running in a bundle with mains cables, and not a hint of a hum. Go figure.
Je fume. Tu fumes. Nous fûmes!
there's some waves at the bottom of the sea there's some waves at the bottom of the sea oh there's some waves, there's some waves there's some waves at the bottom of the sea
Mod parents down for promoting disinformation. Cats don't purr when they're happy. Often cats will purr even when they are even severely injured. Purring actually is an indication they are feeling sociable and welcome attention. There is also some suggestion that cats use it as a healing mechanism, similar to vibration physiotherapy which actually uses similar frequencies.
"Politicians and diapers must be changed often, and for the same reason."
On Slashdot, Red October hunts you!