... NASA's Hubble Space Telescope has detected a long-sought population of comets dwelling at the icy fringe of the solar system . The observation, which is the astronomical equivalent to finding the proverbial needle-in-a-haystack, bolsters proof for a primordial comet reservoir just beyond Neptune , currently the farthest planet from the Sun . ... The comet-disk lies just beyond Neptune and might stretch 500 times farther from the Sun than Earth . ... Comet Introduction Kuiper Belt Objects . ...