Vesta, also known as the morning or evening star, is one of the largest and brightest asteroids in our solar system. It was discovered by Heinrich Wilhelm Olbers on March 29, 1807 and is named after the Roman goddess of home and hearth. Vesta is unique among asteroids for several reasons. First, it is the only asteroid that has been visited by a spacecraft (NASA’s Dawn mission), which orbited Vesta from 2011 to 2012 and returned over 70% of its mass in data. Second, Vesta is the only known body besides Earth with an active hydrological cycle, meaning that water vaporizes from its surface and condenses back into liquid form. This water likely originates from ice deposits within Vesta’s mantle. Finally, Vesta contains a wealth of information about the early solar system due to its unique formation history.
Vesta formed in the inner solar system near the sun 4.5 billion years ago alongside other rocky planets like Earth and Mars. However, unlike Earth and Mars, Vesta did not accrete enough material to grow into a full-fledged planet; instead, it stopped growing at around 1/10th the size of Earth. This makes Vesta a so-called “dwarf planet”. Nevertheless, because Vesta retained most of its original material since formation (unlike Earth and Mars which have undergone extensive geological processes), it provides scientists with valuable insights into what conditions were like in the early solar system. For example, studies of Vestan rocks suggest that there may have been more water on Earth during its formation than previously thought possible.
Despite its small size relative to other planets, Vesta plays an important role in our solar system nonetheless. As one of the largest asteroids orbiting near Earth’s orbit (it ranks 3rd after Ceres and Pallas), collisions between Earth and objects like Vesta are thought to have played a role in delivering water to our planet early in its history – a theory supported by evidence of ancient hydrothermal activity on Vestan surfaces! Additionally, because Vestan rocks are some of the oldest surviving materials in our solar system – dating back 4 billion years – they provide clues about how planets first formed around stars similar to our own sun