Vesta is the brightest asteroid and the second most massive object in the asteroid belt. It is named for the ancient Roman goddess of the hearth and is the only asteroid ever visible with the naked eye. Found on March 29, 1807, by Heinrich Olbers, it was the fourth minor planet to be discovered. It revolves around the Sun in 3.6 terrestrial years and has an average diameter of about 520 km (320 miles). Its surface composition is basaltic.

Up to 1995 getting a good portrait of Vesta was difficult. Using the Hubble Space Telescope the best images ever of Vesta were captured in May 1996 because of its close proximity to Earth. The first space mission to Vesta will be NASA's Dawn probe, which will enter orbit around the asteroid for nine months in 2010-2011.

Vesta is the most geologically diverse asteroid, it shows light and dark features much like our Moon. The surface of Vesta features a giant crater which is 459 km (285 miles) across  and is evidence of an impact with another object. Vesta's age is about the same age as the Sun (4.5 billion years).

Huge Crater on Vesta

The huge crater on Vesta was found by using the Hubble Space Telescope's Wide Field Planetary Camera 2. Measuring about 460 kilometres (285 miles) in diameter  the dent is considerable, in relation to the size of the potato-shaped Vesta, which is about 330 miles in diameter.

Tailing Vesta through space is a family of smaller asteroids with similar geochemical make-up which had previously puzzled astronomers. But with the discovery of the huge crater astronomers can now deduce that the smaller objects, some small fragments of which eventually reach Earth as meteorites, ultimately originated from this blast of the ancient past.

Researchers believe these chips off the old asteroid account for a low percentage of the volume carved out. However, the minor planet is believed to be the origin of basaltic achondrite HED meteorites, which have evidence of a variety of volcanic materials. These materials are similar to the basalts that cover the ocean floors of the Earth and many surface volcanoes such as on Hawaii. These distinctive meteorites comprise six percent of all meteorites that fall to the Earth; thus it is possible that this one giant crater has indirectly supplied a noticeable fraction of the meteoritic material reaching earth in recent times.

Interesting Books

Beyond: Visions of the Interplanetary Probes by Michael Benson
From Amazon.com, Amazon.co.uk, Amazon.Ca

Impact!: The Threat of Comets and Asteroids by Gerrit L. Verschuur
From Amazon.com, Amazon.co.uk

Asteroid Impact by Douglas Henderson (Illustrator), Toby Sherry (Editor), Doug Henderson
From Amazon.com, Amazon.co.uk

Encyclopaedia of the Solar System by Lucy-Ann McFadden
From Amazon.com, Amazon.co.uk

Did you know?

Vesta was the virgin goddess of the hearth, home, and family in Roman mythology. Though she is often mistaken as analogous to Hestia in Greek mythology; she had a large, albeit mysterious role in Roman religion long before she appeared in Greece. Vesta was much more important to the Romans than Hestia was to the Greeks. Little is known about the goddess, as unlike other Roman deities, she had no distinct personality, was never depicted and went without mention in myths. Vesta's presence was symbolized by the sacred flame that burned at her hearth and temples.

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Updated: Saturday 28th, September, 2010