Saturn’s Double Light Show

In January and March 2009, astronomers using NASA's Hubble Space Telescope took advantage of a rare opportunity to record Saturn when its rings were edge-on, resulting in a unique movie featuring the nearly symmetrical light show at both of the giant planet's poles. It takes Saturn almost thirty years to orbit the Sun, with the opportunity to image both of its poles occurring only twice during that time.

The light shows, called aurorae, are produced when electrically charged particles race along the planet's magnetic field and into the upper atmosphere where they excite atmospheric gases, causing them to glow. Saturn's aurorae resemble the same phenomena that take place at the Earth's poles.

The 2009 Hubble Advanced Camera for Surveys observations have allowed astronomers to monitor the behavior of Saturn's poles in the same shot over a sustained period of time and to analyze the planet's northern and southern lights simultaneously. The northern auroral oval appears to be slightly smaller and more intense than the southern one, implying that Saturn's magnetic field is not equally distributed across the planet; it is slightly uneven and stronger in the north than the south.

About the colours

This image was originally black and white and recorded only overall brightness. These brightness values were translated into a range of bluish hues. Such color "maps" can be useful in helping to distinguish subtly varying brightness in an image.

About the data

The image was created from Hubble data from proposals 11566 and 11984 : J. Nichols et al.

The science team comprises: J. Nichols, S. Badman, and E. Bunce (University of Leicester), J. Clarke (Boston University), S. Cowley (University of Leicester), F. Crary (Southwest Research Institute), M. Dougherty (Imperial College, London), J.-C. Gerard and D. Grodent (University of Liege), K. Hansen (University of Michigan), W. Kurth (University of Iowa), D. Mitchell (JHU/APL), W. Pryor (Central Arizona College), T. Stallard and L. Talboys (University of Leicester), and S. Wannawichian (Boston University).