NASA probe Dawn reveals secrets of Vesta, an asteroid older than Earth

In what could possibly be the last vestige of the original rocky matter that came to form the planet earth, the asteroid, Vesta, is being described by scientists as the last of its kind.

According to a new study published in the magazine, Science, scientists at NASA using data from the probe, Dawn, have discovered that much like Earth and other planets in the solar system, Vesta has a metal-rich core and is one of the last examples of the kind of rocky material that bound together to form the planets of the solar system.

Vesta itself is one of the largest asteroids in the asteroid belt, measuring well over 500 kilometres and according to the new NASA findings, the metal core of the asteroid represents 40 per cent of the asteroid’s radius and 18 per cent of its mass, being 220 kilometres across.

From Dawn’s detailed 10-month study of the asteroid, researchers have surmised that Vesta is possibly one of the oldest bodies in the solar system, forming roughly two million years ago, even before the formation of the planets. It is believed that other ‘debris’ like Vesta went onto contribute to the formation of the planets, while Vesta remained.

Commenting upon this ‘reassessment,’ Dawn's deputy principal investigator from NASA's Jet Propulsion Laboratory, Dr. Carol Raymond said, "This mission at Vesta has been a spectacular success. It's transformed Vesta from a fuzzy orb into a planetary body, which has exceeded our expectations in many ways."

Dr. Raymond also shed light on Vesta’s ‘singular’ status, "Vesta is special because it has survived the intense collisional environment of the asteroid belt for billions of years, allowing us to interrogate a key witness to the events at the very beginning of the Solar System."

The researchers were also able to establish a direct link between Vesta and the occurrence of HED (howardite-eucrite-diogenite) class meteorites, saying that it accounted for all the HED meteorites that fall to earth and this association will now allow researchers to directly study materials that existed from before the creation of the solar system from the HED samples that they have.

The probe, Dawn will continue to study Vesta until august of this year, when it will embark on its journey to study bigger brother, Ceres. Dawn will next try to study the asteroid’s north pole. Speaking about this, Dr Jim Green, head of planetary science at NASA said, "With Dawn's ion engines, which are running much better than predicted, it really enables us to stay at Vesta longer. We're very excited about that because it will enable us to map the unknown region. That region is very important to look at now that we know about the Rhea Silvia impact basin. How that impact might affect the northern hemisphere will now be revealed."

(http://www.bbc.co.uk/news/science-environment-18027933)