... Andromeda Island Universe . ... But without a telescope, even this immense spiral galaxy - spanning over 200,000 light years - appears as a faint, nebulous cloud in the constellation Andromeda. ... Thin Rings Around Polarized Saturn . ... How thin are the rings of Saturn? Brightness measurements from different angles have shown Saturn's rings to be about one kilometer thick, making them many times thinner, in relative proportion, than a razor blade. ... Apollo 17: Last on the Moon . ...