When is an Asteroid Not an Asteroid? - NASA Jet Propulsion Laboratory

When is an Asteroid Not an Asteroid? - NASA Jet Propulsion Laboratory Please take the time to read this. Long thought to be an asteroid, Vesta is actually a highly developed, complex world, illustrating once again that there is far more diversity in our solar system and others than ever assumed. As stated in an earlier entry, Vesta and Pallas are quite different from asteroids and most Kuiper Belt Objects, and as such, should be classed in a category of their own. The suggested term for these two worlds is "protoplanets," meaning planetary embryos, or objects that were in the process of becoming planets when their development was halted, possibly due to the gravitational influence of Jupiter. More information is coming, as the Dawn mission will arrive at Vesta in July 2011.