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Sizing Up Space Rocks: Vesta – a Clear Winner!

July 19th, 2011

Image Credit: NASA/JPL-Caltech/JAXA/E

After nearly four years traveling through space, the NASA Dawn spacecraft reached its destination and entered orbit around the asteroid Vesta on 16 July 16th.

Scientists will create detailed maps and elevation models of this celestial body, which is located in the main asteroid belt between Mars and Jupiter.
Dawn’s data gathering is expected to shed light on the history of the Solar System.

With a mean diameter of 520 kilometers, the irregularly shaped Vesta is one of the larger asteroids.

In previous images – for example, those acquired by the Hubble Space Telescope – scientists discovered a large, circular depression with a diameter of roughly 460 kilometers with a vast mountain in the centre at the asteroid’s South Pole.

This deep “hole” is probably the result of a collision with another asteroid. The fragments resulting from impacts on Vesta orbit the Sun as meteorites; some have even made their way to Earth.

This composite image shows the comparative sizes of nine asteroids.

Up until Dawn’s arrival at Vesta, Lutetia — with a diameter of 81 miles (130 kilometers) — was the largest asteroid visited by a spacecraft, which occurred during a flyby.

As you can see, Vesta dwarfs all other small bodies in this image!

By Leonard David