spacetoday.net: Clouds mark change in seasons on Neptune

Posted: Tue, May 20, 2003, 10:32 AM ET (1432 GMT)
Neptune image from HST in 2002 (U. Wisc.)

Planetary scientists have spotted a change in cloud patterns on Neptune that they believe is linked to changing seasons on the distant planet. Hubble observations of Neptune over the last six years have shown that the planet has progressively brightened because of an increase in banded cloud formations in the planet's southern hemisphere. The seasonal change is somewhat surprising because the planet is thirty times farther from the Sun than the Earth, and thus receives 1/900th the radiant energy; that energy drives the weather patterns on Earth and presumably Neptune as well. While the planet also has an internal source of energy, the combination is still too small to adequately describe the dynamics of Neptune's atmosphere, according to University of Wisconsin scientists