New Horizons is approaching Pluto! Let's see its timeline of approaches and discoveries: * July12th UTC 11 AM:A ring, designed R/2015(134 340)Pluto 1, is discovered. * July12th UTC 1 PM:The new data suggests the mass and diameter of Pluto is (1.3157±0.0012)×1022 kg and 2386.45±0.97km. * july13thUTC 2AM:A photograph suggests a ring arc around Styx.(Ring arcs are not necessarily rings. These are the so-called proto-rings, which are not that disrupted by the host planet/space object's gravity yet(in this case, Pluto). The ring arc is always formed by an big asteroid impact on a moon that throws(more like blast) materials outward from the moon.) This is the first such system around a minor planet. * July 13th UTC 3AM: a moon is discovered and named S/2015(134 340)Pluto I. It is t