Ah, the "hum of the earth that is not a hum at all". Apparently, our planet (and all other planets for all we know) emits electromagnetic radiation where the wavelength is the same as the planet's circumference. It's not a sound as many people tend to believe, it's a kind of electromagnetic radiation, much like light, nuclear radiation and x-rays only extremely low frequency (ELF). Exactly what it is is hard to say. It may be a gravity thing or some kind of radiation exhaust or leftovers from the nuclear processes inside the Earth's nucleus or core, or a host of other things. Since people ha