Pluto may have been stripped of its full planetary epaulettes, but not of its ability to deliver surprises, and 'new' images from the Hubble delivered one. (Commenter Ferrard Carson alluded to this in a comment to the last post.) Pluto is undergoing seasonal changes on its surface, and with startling abruptness, considering that Plutonian seasons are about 62 years long. UV light from the Sun breaks up methane ice, leaving a dark sludgy stuff called tholin.
The methane ice and tholin put me in mind of Pluto in Heinlein's Have Spacesuit, Will Travel.
'New' is in scare quotes because the Hubble imagery was obtained in 2002-2003, but it has taken until now to process the information - far below the nominal resolution even of the Hubble - to tease out the information. The level of detail they were able to recover, as a rather charming aside, is comparable to our naked eye view of the full moon. Evidence of surface changes comes from earlier Hubble imagery dating back to 1994.
So Pluto now joins Earth and Mars among
planets bodies whose surfaces change dramatically as a result of seasonal changes in surface ice.
Though from another perspective this behavior is also a bit comet-like, a reminder that the displaneting of Pluto, however much it crushed schoolkids (most got over it), was a byproduct of all we are starting to learn about the outer Solar System.
When I was a kid, Pluto was the lonely outer sentinal. Beyond was only interstellar night, and a few tumbling comets (though rocketpunk SF was fond of adding a tenth planet, often called Proserpina). Now Pluto is instead the king of the Kuiper Belt - Eris, slightly larger and three times farther out, belongs to a separate class of remote objects, the 'scattered disk.'
Instead of being the end of the Solar System is the near shore of an entire realm, orbiting in the solar twilight, only just starting to be known.
Related post: I contemplated the immense outer system last year.