Dawn Mission Achieves First-ever Orbit around a Dwarf Planet

This year is truly the Year of the Dwarf Planet! Earlier today, NASA’s Dawn spacecraft slipped into orbit around dwarf planet Ceres and settled in for a long-term study of this little world. Think about what this achievement means. First, this isn’t the first world the spacecraft has orbited. It also studied the asteroid Vesta for about a year. That makes it the only spacecraft (so far) to orbit two extraterrestrial targets.

Second, it will be the first of two missions this year to give us up-close looks at dwarf planets. The long-awaited New Horizons mission to Pluto and beyond will finally show us some high-resolution details of Pluto, the infamous dwarf planet that is at the heart of so much controversy about what the word “planet” means. I hope for all our sakes that the science we get from these two missions FAR overshadows the controversy. These are worlds. They ARE planets. The term “dwarf” in their  names is not an insult — it’s a descriptor loaded with a LOT of meaning to planetary scientists, who should know what planets are (despite the best efforts of the IAU to dictate to them otherwise). Just as there are types of stars (dwarfs, giants, etc.) and types of galaxies (dwarfs, lenticulars, spirals, etc.), there are types of planets. The cosmos is big enough to contain all the types we want. We just need to recognize that and move on.

Already, Ceres is tantalizing us with a bright spot, a cratered surface, and various other characteristics. This tells ME that this little world, as well as Pluto, has some secrets to share, and that those secrets will enlarge our understanding of the solar system. Knowing our own neighborhood is an important first step toward understanding worlds far beyond our own star, and it helps us “get” where we are in the cosmos. So, stay tuned. Ceres has a lot to show us, and in a few months, Pluto will take its place on center planetary stage and continue the show of a lifetime.