The scientists think those white, vein-like growths inside the pit could indicate geologic activity in the "recent past," which still means a few million years ago or so. Dawn's other images also show that Ceres doesn't have as many large impact craters as scientists thought, and that there's one particular crater called Haulani that's composed of different materials than the rest of the dwarf planet.
Besides taking photos, the spacecraft used its Gamma Ray and Neutron Detector (GRaND) to measure Ceres' elemental composition. The instrument detected fewer neutrons near its poles, indicating a big amount of hydrogen concentration. It's a possible proof that there's ice -- the same ice made of water we're used to -- in its polar regions. NASA discusses these findings (and more) in the video below, while showing more photos of the largest object in the asteroid belt.