Image of IMAGE in space

IMAGE Discovers a One-Sided Theta Aurora

Theta Aurora

Although most observers prefer to marvel at the spectacular curtains and drapes of an aurora from lower-latitude locations, it has been known for over 100 years that inside the polar auroral oval, there are also a variety of interesting phenomena to watch for. One of these, and rather rate at that, is the theta aurora. From space, the auroral oval sports a band of light parallel to lines of longitude, which ties opposite parts of the oval together into the greek letter Theta. It has also been known for decades that the north and south pole auroras are very similar during a storm event; a phenomenon called Conjugacy. The IMAGE FUV instrument studies the theta aurora formed during November 5, 2001 and April 18, 2001 and discovered that these theta aurora did not have partners on the other pole!

(2003: Ostgaard et al.)

Related IMAGE Discoveries

Additional Information

Auroral Oval - The shape that the aurora borealis or aurora australis takes when viewed from space. AUrora occur in two ring-like zones that encircle the polar regions.

Auroral COnjugacy- Because Earth's magnetic field is generally symmetrical, aurora should have a similar shape in each hemisphere. COnjugacy implies that the shapes may be overlain are are congruent in shape.

IMAGE experiments
Useful Web Resources

Return to the IMAGE Discoveries page


Dr. S. Odenwald,, +1-301-286-6953
NSSDC, Mail Code 630, NASA Goddard Space Flight Center, Greenbelt, MD 20771
NASA Approval: J. L. Green,
Rev. 1.0.0, 24 July 2004, EVB II