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发帖数: 1994 | 1 Credit: G. Neukum (FU Berlin) et al., Mars Express, DLR, ESA
Explanation: Why is this small object orbiting Mars? The origin of Phobos,
the larger of the two moons orbiting Mars, remains unknown. Phobos and
Deimos appear very similar to C-type asteroids, yet gravitationally
capturing such asteroids, circularizing their orbits, and dragging them into
Mars' equatorial plane seems unlikely. Pictured above is Phobos as it
appeared during last week's flyby of ESA's Mars Express, a robotic
spacecraft |
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