Comet and Aurora Over Alaska . ... Just to the lower left, however, well in the background, is something harder to spot: Comet Ikeya-Zhang , the brightest comet of recent years. Although the aurora faded in minutes, the comet is just now beginning to fade . ... The comet is actually a giant dirt-covered snowball that spends most of its time in the outer Solar System -- to where it is now returns. The above photograph was taken on March 20 when Comet Ikeya-Zhang was near its brightest. ...