Acquired in March 2007, this eerie image from Hubble’s Advanced Camera for Surveys’s ultraviolet camera show glowing auroral emissions, always present in Jupiter’s polar regions.
The aurora is hundreds of kilometers wide and about 250 kilometers above the planet. It is caused by electrically charged particles striking atoms in the upper atmosphere from above, the same process involved in Earth’s aurorae (except that Jupiter’s magnetic field is orders of magnitude more powerful than Earth’s!)
And here’s a look at Jupiter’s southern aurora as well:
These images were taken as New Horizons was passing by Jupiter, grabbing some momentum to head out toward Pluto. It is currently 22 AU away from Earth, the closest to Pluto any human spacecraft has ever gone.
Jupiter’s giant aurorae had also been previously imaged by the Galileo spacecraft.
NASA’s Juno spacecraft, currently en route to Jupiter to arrive in 2016, will study Jupiter’s magnetic field in depth, as well as aspects of the giant planet’s atmosphere.
Image credits: NASA, ESA, J. Clarke (Boston University), The Hubble Heritage Team (STScI/AURA), and J. Spencer (Southwest Research Institute).