There's been talk about changes in other planets. The following is from BBC news:

"Something unexpected is happening on distant Pluto - the outermost planet. Although it is receding from the Sun, its atmosphere is getting thicker, puzzling astronomers who expect it to "freeze-out" and contract in about 10 years. The recent changes were noted as a result of a rare cosmic alignment last year. Pluto passed in front of two faint stars whose light was dimmed by its atmosphere before being cut-off by its disc.

Data from these events indicate that Pluto's tenuous atmosphere has become swelled in the past 14 years since the last time such an occultation was observed.

What is happening on the planet will only be answered by the arrival of the Pluto-Kuiper Express mission, Pluto's first probe. It is due for launch in 2006, to reach Pluto about a decade later."