Asteroid Vesta is one of the handful of asteroids visited by a spacecraft. Asteroids are believed to be debris left over from the formation of our Solar System. Understanding these small bodies will help us understand the formation of the Solar System and the existence of greater terrestrial bodies. A spacecraft hovering near an asteroid yields a lot of information about the body like its mass and density. Some of the most useful information provided by the spacecraft are the spectacular photographs of the body which help us understand its history.
NASA's Dawn Spacecraft was launched in 2007 to study the two largest bodies of the Asteroid Belt, Vesta and Ceres (the dwarf planet). The mission has provided us with a lot of information about Vesta and will fly by Ceres in 2015.
Impressive new information about Vesta was just released by NASA. The principal investigator Chris Russell in a recent interview said that Vesta resembles a terrestrial dwarf planet more than an asteroid. He suggests this is due to the fact that not only is the body differentiated (all terrestrial planets are differentiated), but it also contains an iron core and has surface features like that of the terrestrial planets.
Here is the link to the article from Space Daily for more information: http://www.spacedaily.com/reports/Is_Vesta_the_Smallest_Terrestrial_Planet_999.html
