The surface of Varuna is dark, with a measured geometric albedo of 0.127 based on thermal observations in 2013. Varuna's geometric albedo is similar to that of the possible dwarf planet , which has a geometric albedo of 0.109. Varuna was initially thought to have a much lower geometric albedo, as early ground observations of Varuna's thermal emissions from 2000 to 2005 estimated albedo values ranging from 0.04 to 0.07, around eight times darker than Pluto's albedo. Later thermal measurements of Varuna with space-based telescopes refuted these previous albedo measurements: Spitzer measured a higher geometric albedo of 0.116 while further thermal measurements from Spitzer and Herschel in 2013 estimated a geometric albedo of 0.127.