Vesta is now seen as the only known layered, iron-cored, planetary building block to survive the solar system earliest days, forming in a similar way to the terrestrial planets and Earth’s moon.
The so-called Dawn spacecraft, launched by NASA, has yielded to researchers the very first orbital analysis to be obtained about giant asteroid Vesta, providing stunning new insights into the way it came into being. and how, materially speaking, it resembles both the Earth and the moon in composition.
Now revealed by satellite data to be a massive, special early solar system fossil – the surface much more diverse and varied than had been contemplated – scientists confirming several ways in which Vesta, more than other asteroids, bears close resemblance to a small planet or our moon, as told in the latest Science magazine.
The inspection of the asteroid by satellite Dawn confirmed the broad theories held about the history of the body, helping fill in details impossible to know without the close visit, the satellite resident around Vesta of nearly a year – enabling researchers to more clearly gauge the planet-like qualities.
Vesta is now seen as the only known layered, iron-cored, planetary building block to survive the solar system earliest days, with a geologic complexity attributable to a process separating it into crust, mantle and iron core – some 68 miles wide – around 4.56 billion years ago, forming in a similar way to the terrestrial planets and Earth’s moon.
Dawn observed a pattern of minerals exposed by deep gashes created by space rock impacts, which may support the idea the asteroid once had a subsurface magma ocean. A magma ocean occurs when a body undergoes almost complete melting, leading to layered building blocks that can form planets. Other bodies with magma oceans ended up becoming parts of Earth and other planets.
One distinct group of meteorites found on Earth did, it is now confirmed come originally from Vesta, these objects representing some 6% of all meteorites falling onto the Earth, their chemical signatures of pyroxene, matching those of rocks on the surface of the asteroid, making it one of the largest single Earth meteorite sources.
The central peak on Vesta, in the southern hemisphere Rheasilvia basin is much higher and wider than the central peaks on bodies like the moon, the asteroid bearing similarities to the small icy moons of Saturn, a surface of light and dark markings not matching the predictable patterns seen on our moon surface.
Satellite Dawn Imagery has revealed how Vesta has been battered throughout its history and the details of details of ongoing collisions, the data enabling researchers to can date two giant impacts that rocked the asteroid between one and two 2 billion years ago. Dawn was launched in 2007, and began exploring Vesta middle of 2011, due to depart the asteroid on August 26 heading for next study target - dwarf planet Ceres -which it is hoped it will reach in 2015.