Hubble Space Telescope images of Jupiter’s and Saturn’s ultraviolet (UV) auroras
 
 
These images of Jupiter’s northern UV auroras were obtained using the Advanced Camera for Surveys onboard HST in February 2007. Image credit: Boston University and NASA.
 
 
 
These images of Saturn’s southern UV auroras were obtained using the Advanced Camera for Surveys onboard HST in January 2007. Image credit: Boston University and NASA.
 
 
 
And these images of both Saturn’s northern and southern auroras were obtained during a rare opportunity in 2009, when the view from Earth was nearly in the equatorial plane due to the planet’s equinox.  For more information, visit ESA’s Hubble website for a “Hubblecast” about these images:
 
 
Image credit: University of Leicester, NASA, ESA, Jonathan Nichols.
 
 
Here are a few selected stills:
 
Image credit: Boston University and NASA.
 
 
 
 
Image credit: University of Leicester, NASA, ESA, Jonathan Nichols.
 
 
 
Image credit: University of Leicester, NASA, ESA, Jonathan Nichols.
 
 
Exoplanets
 
An artist’s impression of a Jupiter-like exoplanet with a volcanic moon internal to the magnetosphere.  The centrifugally-driven outflow of plasma from the moon generates electric currents which flow around the magnetic field and generate auroras in the polar upper atmosphere, and radio waves which are emitted in beams away from the polar magnetic field. I showed in a MNRAS paper that fast-rotating planets orbiting stars that shine brightly in the Extreme Ultraviolet (EUV) may be detectable using next-generation radio telescopes, such as LOFAR.  Image credit: Emma Cowley.