data – n. facts about something that can be used in calculating, reasoning, or planning

tilt – v. to move or shift so as to slant or tip

axis – n. the imaginary straight line that something (such as the Earth) turns around

spin – v. to turn or cause someone or something to turn around repeatedly

rotation – n. the action or process of rotating on or as if on an axis or center

reflection – n. an image that is seen in a mirror or on a shiny surface

galaxy – n. any of the very large groups of stars and associated matter that are found throughout the universe

diameter – n. mathematics : the length of a straight line through the center of an object or space

greenhouse effect – n. warming of the lower atmosphere of the earth that occurs when radiation from the sun is absorbed by the earth and then given off again and absorbed by carbon dioxide and water vapor in the atmosphere gases

mission – n. a definite military, naval, or aerospace task