Dawn mission to Ceres
The Dawn mission, when a probe orbited Ceres, found that these were patches of sodium carbonate. These had probably formed when salty water bubbled up from Ceres' "muddy" interior, the water then sublimating into space.
Judging from the amount of mixing the surface gets from meteorites, the percolation of brine to the surface is still happening, meaning Ceres is still volcanically active.
You can see Ceres. It's a bit of a challenge, though.
Ceres is magnitude 7.7, so you're going to need a medium sized telescope, a tracking mount and a camera. You'll need to figure out where it's going to be by using Stellarium, Cartes du Ciel or some similar planetarium program. Ideally, you'll be doing this at the time of year when Ceres rises at about sunset sets at about sunrise, which would mean it's well-placed for observation. If you've got a go-to mount, it can be very useful to find closest star with an SAO catalogue number - that way you can find that star with your mount.
To see Ceres, take an exposure of about 30 seconds while your mount is tracking. Then about an hour later, come back and take another one. Better still, keep taking images for a few hours. Ceres will be the dot that moves slowly across the face of the other stars. And I do mean slowly. My field is about 1.8° wide, and Ceres takes about 10 days to cross this.
...and apologies to Douglas Adams.