NASA Captures Stunning Images Revealing Complex History of Two Near-Earth Asteroids

Asteroid Didymos and its moonlet Dimorphos, 2.5 minutes before DART impact [Image: NASA]

NASA's DART spacecraft captured high-resolution images of asteroids Didymos and Dimorphos before intentionally colliding with the latter in a groundbreaking planetary defense test. These images have provided valuable insights into the complex history of these two rocky bodies and shed light on the formation of binary asteroid systems.

Analysis of crater patterns and surface strength suggests that Didymos formed around 12.5 million years ago, while Dimorphos formed approximately 300,000 years ago. Researchers believe that Didymos originated in the asteroid belt between Mars and Jupiter before being propelled into the inner solar system.

Examination of the largest boulders on both asteroids reveals that they are composed of rocky fragments formed from the catastrophic destruction of a parent asteroid.

The two asteroids, classified as "rubble piles," are composed of loosely held-together rocky fragments. Their surfaces are littered with enormous boulders, with the largest ones comparable to a school bus and a soccer field in size. Olivier Barnouin, a planetary geologist, noted that the surfaces of both asteroids are incredibly weak, even softer than loose sand.

Further analysis revealed that Dimorphos likely originated from material ejected from Didymos' equatorial region due to its rapid rotation in the past. Didymos currently rotates once every 2.25 hours.

On September 26, 2022, the DART spacecraft successfully collided with Dimorphos at a speed of approximately 14,000 miles per hour, demonstrating the ability to deliberately alter an asteroid's course. Notably, Didymos and Dimorphos do not currently pose a threat to Earth.

In addition to changing its course, the collision also caused a slight deformation of Dimorphos's shape, providing scientists with valuable information and a deeper understanding of binary asteroid systems.

According to Barnouin, binary asteroid systems, which consist of a primary asteroid and a smaller companion, account for a significant proportion of near-Earth asteroids, specifically around 10-15%. He emphasized that every new observation and discovery in this field provides valuable insights into the formation and evolution of asteroids, especially the smaller ones, ultimately expanding our knowledge of these celestial bodies.