Viewed from afar, Earth is a strong emitter of radio waves in the range from below 100 kHz to nearly 1 MHz, peaking around 300 kHz. This naturally occurring Auroral Kilometric Radiation (AKR) is stronger than any man-made transmissions at such frequencies, averaging 10 million watts and sometimes peaking at a billion watts. The AKR is not, however, detectable at ground level, being reflected by the ionosphere’s E-layer at 110 km altitude. Several of the other major planets of the Solar System also have their own auroral signatures. Observation of these is beyond amateur means, but it is of interest to compare the aurorae that occur at, say, Jupiter and Saturn, with that of our homeworld.
KeywordsSolar Wind Hubble Space Telescope Auroral Oval Galilean Satellite Auroral Activity
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