... Put a satellite in a circular orbit about 42,000 kilometers from the center of the Earth (36,000 kilometers or so above the surface) and it will orbit once in 24 hours. ... WISE Infrared Andromeda . ... The small world is near opposition (opposite the Sun in the sky) and closest to Earth. ... This past weekend, humanity's Saturn-orbiting Cassini spacecraft passed as close to Saturn's small moon Calypso as it ever has, and imaged the small moon in unprecedented detail. ... Waterway to Orbit . ...