Dwarf Planets

Here are the biggest mysteries about the dwarf planet Ceres, according to the principal investigator of NASA's Dawn mission, which is studying the intriguing world up close.

Both the dwarf planet Ceres and Pluto's moon Charon may be covered with material similar to the graphite in a pencil.

The discovery of strange halo-like craters on Pluto has raised a new mystery about how the odd scars formed on the icy world.

See photos and illustrations of the distant icy dwarf planet Makemake.