Tl;dr: it's a smallish squarish rock. There is, however, a genuinely impressive monolith on Mars' moon Phobos. It's about the size of a 30-story building. htt

Tl;dr: it's a smallish squarish rock. There is, however, a genuinely impressive monolith on Mars' moon Phobos. It's about the size of a 30-story building. http://en.wikipedia.org/wiki/Phobos_monolith http://en.wikipedia.org/wiki/Phobos_monolith