NASA’s OSIRIS-REx mission found Bennu’s surface covered in large boulders that cool quickly, defying earlier expectations. Detailed analysis of rock samples has now uncovered intricate cracks inside these boulders, solving a long-standing puzzle about the asteroid’s thermal behavior.
- Bennu’s surface is dominated by large, cracked boulders.
- Hidden cracks explain the asteroid’s low thermal inertia.
- Advanced imaging and thermography techniques confirmed findings.
What happened
The OSIRIS-REx mission encountered asteroid Bennu in 2018 and was surprised to find it covered mainly in huge boulders rather than smooth regolith expected from previous observations. This rocky terrain presented challenges for sample collection and raised questions about the asteroid’s thermal properties.
Earlier measurements from NASA’s Spitzer Space Telescope showed Bennu’s surface heats up and cools down quickly, a trait termed low thermal inertia. Typically, large solid rocks retain heat for longer periods, so Bennu’s rapid heat loss was puzzling given its boulder-strewn surface.
Why it feels good
The samples returned by OSIRIS-REx gave scientists a chance to examine Bennu’s surface materials in detail. Researchers discovered that the boulders are far more porous than expected and contain widespread networks of tiny internal cracks. This unexpected structure increases the surface area and pathways for heat to escape, explaining the asteroid’s unusual thermal behavior.
Collaborative studies involving Japanese scientists using lock-in thermography confirmed these findings by showing how heat quickly spreads through and dissipates from these cracked rocks. This breakthrough clarifies a key aspect of Bennu’s nature, enhancing our understanding of small body surfaces in space.
What to enjoy or watch next
NASA continues to analyze Bennu’s samples using sophisticated X-ray computed tomography, which allows 3D imaging of rock fragments without contamination. This method helps researchers visualize the complex internal cracks in greater detail and refine models of heat transfer in asteroid materials.
Future missions and ongoing analysis will build on these findings to better comprehend the evolution and surface processes of Bennu and other asteroids. These insights not only inform planetary science but also aid planning for asteroid exploration and mining efforts.