# Does earth itself emit electromagnetic waves?

(.... and if so, of what frequency and amplitude)?

This Skeptics.SE question about nonsense called 'geopathic stress' made me wonder if and how earth itself emits electromagnetic waves.

We need moving charges for that, and I can hardly imagine that things like moving magma or 'moving' radioactive minerals would 'emit' anything, but maybe I'm missing something?

I'm not asking about atmospheric phenomena, or about externally introduced electrical currents (man made, lightning).

• To anyone answering this question, the key is electromagnetic WAVES which would be different from the electromagnetic field, made by Earth's solid inner core spinning in the molten outer core that creates the Earth's magnetic field lines (used by compasses) and gives rise to the van Allen Radiation Belts. Think of the Earth equivalent to brain waves that can be detected by an Electroencephalogram. – Fred Jun 3 '15 at 7:37
• @Fred Thanks, good distinction. Although if regular ('higher' frequency) fluctuations in that field existed, they would qualify as waves, wouldn't they? – Jan Doggen Jun 3 '15 at 10:13
• Also infra-red (which the Earth most definitely emits!) is an electromagnetic wave. I think you mean something of longer wavelength, but even then black body radiation will emit some of the wavelengths longer than the infra red peak (eg. microwaves) – winwaed Jun 3 '15 at 13:00
• All matter emits electromagnetic radiation, which would certainly include Earth. – b1nary.atr0phy Aug 27 '19 at 2:51

## 1 Answer

Yes, the earth emits electromagnetic radiation.

It emits infrared radiation with wavelengths of about 1 µm to 1 mm. This is heat, essentially, and much of it radiates into space:

Most if not all of the earth's rocks are radioactive (e.g. because of minerals containing isotopes in the uranium decay chain, such as potassium-40) and emit gamma radiation with wavelengths around $10^{-12}$ m. I'm not sure how much of this radiation would make it through the atmosphere.

You said you're not interested in atmospheric phenomena, but I wonder what the relative contributions of subsurface and atmosphere (e.g. the auroral kilometric radiation), as well as manmade sources, would be to the total signature. The planets emit radio waves (ask a radio astronomer), but I suspect most of that energy is from their atmospheres, since Jupiter and Saturn are especially bright. This book by Vázquez, Pallé and Montañés Rodríguez (2010; Springer) looks like it might address some of this, e.g. in Chapter 4.