According to ScienceDaily, a giant crater on Mars' moon Phobos may hide a dense region of compressed material. The feature is significant because it could help resolve a long-standing question about how Phobos formed.
Scientists have proposed two main possibilities: the moon is an asteroid that Mars captured, or it is debris assembled from an ancient impact on Mars. The presence or absence of a compressed zone beneath the crater would support one of these explanations, according to the source.
Japan's upcoming MMX sample return mission could provide the measurements needed to examine the crater's interior. If successful, it would offer physical evidence about the moon's structure and, ultimately, its origin.