University of Leicester | 04 Aug 2010
Variation of Saturn's UV aurora with SKR phase - JD Nichols et alSpace researchers illuminate ‘one of the most perplexing puzzles in planetary science’
An international team of scientists led by Dr Jonathan Nichols of the University of Leicester has discovered that Saturn’s aurora, an ethereal ultraviolet glow which illuminates Saturn’s upper atmosphere near the poles, pulses roughly once per Saturnian day.
The length of a Saturnian day has been under much discussion since it was discovered that the traditional ‘clock’ used to measure the rotation period of Saturn, a gas giant planet with no solid surface for reference, apparently does not keep good time.
Saturn, like all magnetised planets, emits radio waves into space from the polar regions. These radio emissions pulse with a period near to 11 h, and the timing of the pulses was originally, during the Voyager era, thought to represent the rotation of the planet. However, over the years the period of the pulsing of the radio emissions has varied, and since the rotation of a planet cannot be easily sped up or slowed down, the hunt for the source of the varying radio period has become one of the most perplexing puzzles in planetary science.
Now, in a paper to be published in Geophysical Research Letters (August 6), Nichols et al. use images from the NASA/ESA Hubble Space Telescope of Saturn’s auroras obtained between 2005-2009 to show that, not only do the radio emissions pulse, but the auroras beat in tandem with the radio.
- Geophysical Research Letters (in press) DOI: 10.1029/2010GL044057
