NASA破解小行星贝努岩石快速散热之谜

NASA通过分析OSIRIS-REx任务采集的小行星贝努样本，揭示了该小行星表面快速散热的真正原因1。研究人员利用X射线计算机断层扫描和锁相热成像技术对样本进行检测，发现岩石内部不仅具有高孔隙率，更关键的是存在广泛的微裂隙网络1。这些内部裂隙是导致贝努低热惯性特征的决定因素1。

OSIRIS-REx探测器于2018年抵达贝努，发现其表面被巨大的岩石块覆盖，而非光滑的细粒物质1。早在2007年，NASA Spitzer望远镜的观测已经表明贝努表面具有低热惯性特征，但其成因一直不明1。亚利桑那大学研究人员Andrew Ryan表示，这些岩石内部裂纹遍布，"这正是我们一直在寻找的缺失的拼图"1。

为了确保样本的完整性，X射线计算机断层扫描在密闭手套箱中进行，防止样本与地球环境接触1。这项研究由NASA约翰逊航天中心、亚利桑那大学和日本名古屋大学等机构联合完成，研究成果已发表于《自然通讯》2026年第17卷第1期1。研究人员Ron Ballouz指出，该发现为遥感观测与实际小行星物质的内部结构建立了重要联系1。

NASA researchers have unveiled why asteroid Bennu's surface sheds heat so quickly by analyzing samples collected during the OSIRIS-REx mission.1 The key discovery involves the internal structure of the rocks: beyond their high porosity, the samples contain an extensive network of microfractures throughout their interiors.1 These internal cracks proved to be the critical factor responsible for Bennu's low thermal inertia, according to the team's findings published in Nature Communications in 2026.1

The investigation employed advanced imaging techniques to document this phenomenon.1 Researchers used X-ray computed tomography scanning, conducted inside an enclosed glove box to prevent samples from contacting Earth's atmosphere, combined with lock-in thermography—a method that heats samples with lasers to measure how heat propagates through the material.1 "It turns out that they're really cracked too, and that was the missing piece of the puzzle," explained Andrew Ryan of the research team.1 The findings establish an important connection between remote sensing observations—such as those made by NASA's Spitzer telescope in 2007, which initially identified Bennu's low thermal inertia signature—and the actual internal structure of asteroid materials, as noted by researcher Ron Ballouz.1