This video is built up from still images taken as NASA's Dawn spacecraft closes in on Vesta, its target asteroid. Vesta is big enough to be classed as a "protoplanet" - that is, is almost had enough mass to become the center of a planet. Dawn will do a close inspection of Vesta from orbit and then fly to an even bigger target, Ceres. As NASA puts it, "Dawn's goal is to characterize the conditions and processes of the solar system's earliest epoch by investigating in detail two of the largest protoplanets remaining intact since their formations. Ceres and Vesta reside in the extensive zone between Mars and Jupiter together with many other smaller bodies, called the asteroid belt. Each has followed a very different evolutionary path constrained by the diversity of processes that operated during the first few million years of solar system evolution."
COMMENT: One translation is that we are visiting the biggest and oldest rocks in the solar system. We think they have a lot to tell us about how the solar system formed, and "we" are almost certainly right on that one. On to Vesta!