A recent essay by NASA's chief historian Steven J. Dick reveals that even within NASA, there is substantive disagreement about the origin of Phobos and Deimos, Mars' only moons:
"a great deal remains unknown about the moons of Mars, including even their basic composition and their origin. The attendees at the First International Conference on the Exploration on Phobos and Deimos discussed what was known, what was unknown, and how to find out more. Most continue to believe the moons are captured asteroids, but the capture mechanism is unknown and the scenarios unlikely."
Well, duh. See our previous blog post, guys.
On the Web:
Under the Moons of Mars
Lunar and Planetary Institute, First International Conference on the Exploration of Phobos and Deimos, Nov. 5-7, 2007