... Martian Moon Deimos from MRO . ... Mars has two tiny moons, Phobos and Deimos. Pictured above, in a recently release image by HiRISE camera onboard the Mars-orbiting Mars Reconnaissance Orbiter (MRO), is Deimos, the smaller moon of Mars. Deimos is one of the smallest known moons in the Solar System measuring only about 15 kilometers across. ... A solar prominence is a cloud of solar gas held above the Sun's surface by the Sun's magnetic field. ... Hickson Compact Group 90 . ...