Scientists use lasers to create a 3-D model of asteroid Eros.
Not all asteroids look the same. In fact, the appearance of an asteroid can vary depending on factors like its age, composition and how it evolved. In 2000, after a four-year journey from Earth, NASA’s NEAR Shoemaker spacecraft began circling Eros, the second-largest near-Earth asteroid. Researchers believe that Eros is a pristine leftover from when the solar system formed 4.6 billion years ago. To learn more about Eros, a laser rangefinder instrument aboard the spacecraft pinged the 20-mile-long chunk of rock with approximately 8 million infrared pulses over the course of a year. The light-based measurements yielded information about the height and shape of features on the asteroid’s surface, allowing scientists to construct a detailed 3-D model of its topography. The model helped scientists study the asteroid’s many craters and offered insights into its internal structure. Watch the video for a tour of Eros.