Geology of 433 Eros

By Emerson Speyerer1, Mark Robinson1, and Peter Thomas2


Space rocks, better known as asteroids, orbit the sun at thousands of miles an hour. Too small to be called planets, asteroids are finally getting the attention they deserve. A heightened interest in asteroids and comets arose after the comet Shoemaker-Levy 9. In July of 1994 the comet split in to 21 large pieces and impacted the planet Jupiter. This was the first impact to be observed. If it was possible for a comet hit Jupiter, it was also possible that one can hit Earth.

Since the Galileo flew by Gaspra and Ida and NEAR flew by Mathilde and orbited Eros, researchers and the public have learned many new things about these small bodies. Eros was chosen to be the destination of NEAR because it is a typical near-Earth asteroid, with an odd shape (34 x 13 x 13 km), tilted axis, and elongated orbit (Yeomans 1995). However, most of all, Eros was chosen because of its size. In fact, Eros is one of the largest known near-Earth asteroids, which means more area to cover and a few more features than a small asteroid would have.

On the following pages are examples of features that can be seen in the mosaics, frames, and the orbital movies with summaries of what they are and why the features are important. The features have been broken down into three categories: broad, intermediate, and small scale.

-Broad Scale

  • Tilted Axis
  • Shape
  • Large Craters
  • -Intermediate Scale

    • Grooves
    • Ridges
    • Craters

    -Small Scale

    • Boulders
    • Slides
    • Streamers
    • Ponds

    Images used:

    Default: 146336532-146337216

    Broad Scale: 146336718-146337090

    Intermediate Scale: 129892867

    Small Scale: 135614739-135615999

    1 Northwestern University- Department of Geological Sciences

    2 Cornell University- Space Sciences