Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. (42301) 2001 UR163, also written as 2001 UR163, is a very likely dwarf planet that resides in the scattered disc. It was discovered on October 21, 2001 by the Deep Ecliptic Survey program at Kitt Peak. Light-curve-amplitude analysis shows only small deviations, suggesting that 2001 UR163 is a spheroid with small albedo spots and hence a dwarf planet. 2001 UR163 has the reddest color index of any object in the Solar System. On October 31, 2002, the 3.6 meter Canada-France-Hawaii telescope observed 2001 UR163 set a record red reading of B-R=2.28.