APOD: January 23, 1998 - Jovian Aurora (original) (raw)

Astronomy Picture of the Day

Discover the cosmos!Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

January 23, 1998

Explanation: These two recentlyreleased Hubble Space Telescope close-ups show theNorthern and Southern lights ...on Jupiter.Like aurora on Earth, these Jovianaurora are caused by charged particles funneled into the atmosphere above the planet's North (right) and South poles bymagnetic fields. But Jupiter's magnetic field is extremely large and ionized material expelled fromthe volcanic moon Iois trapped in it creating light shows 1,000 times more intense thanEarth's auroral storms. Charged particles released by Io are also funneled along magnetic flux tubes which form a direct "bridge" to the Jovian atmosphere. The result is auroral hot spots - magnetic footprints 600 or more miles across which race overJupiter's cloud tops. A hot spot is visible in both images as a comet-like feature just outside the polar auroral rings. In these false color ultraviolet images, Jupiter's limb (edge) appears dull brown whilethe auroral displaysare shades of white and blue.