Adrian Dennis / AFP / Getty Images
A. Ivanov / Popova et al. / Science
MarsScientific.com / Clay Center Obs.
Michael Tackett / Warner Bros. / New Line Cinema via AP
NASA / JPL / SwRI / Ken Kremer / Marco Di Lorenzo
Raymond M. Alf Museum of Paleontology
Greg du Toit / Wildlife Photographer of the Year
Chuck Ruehle / Telescopes to Tanzania