All its other instruments were turned off to conserve the meager power from its solar panels. Eventually, astronomers at Johns Hopkins University expect to analyze the data from NEAR and produce detailed measurements of Mathilde's density, volume, and mass. In the meantime, the preliminary conclusions are startling enough. Some, like Mathilde and Eros, NEAR's final destination, have all or part of their orbits inside of Mars. They are the so- called NEAs, Near Earth Asteroids.
Asteroids range from a few miles to hundreds of miles wide.
Given the chance, these hunks of rock probably would have clumped together by gravity to form a planet outside of Mars billions of years ago. What remains are the leftovers from planetary formation, nearly pristine examples of the raw materials of our solar system. At 32 mile wide, Mathilde is somewhat smaller than expected. It is also irregularly shaped, battered and torn by dozens of impacts with rocky bodies smaller than itself. At least five of its craters are larger than 12 miles in diameter and are the results of impacts with bodies a mile or more wide.