Primary evidence for dark matter comes from calculations showing that many galaxies would fly apart, or that they would not have formed or would not move as they do, if they did not contain a large amount of unseen matter. Other lines of evidence include observations in gravitational lensing and in the cosmic microwave background, along with astronomical observations of the observable universe’s current structure, the formation and evolution of galaxies, mass location during galactic collisions, and the motion of galaxies within galaxy clusters. In the standard Lambda-CDM model of cosmology, the total mass–energy of the universe contains 5% ordinary matter and energy, 27% dark matter and 68% of an unknown form of energy known as dark energy. Thus, dark matter constitutes 85%[a] of total mass, while dark energy plus dark matter constitute 95% of total mass–energy content.
Simply put, resistance to the creation of a space frontier originates with the insecurities of Western leaders. First, it is clear that everything changes with the emergence of a frontier. Established power structures are usually shaken, not reinforced. (If this is not clear, try reading Walter Prescott Webb's The Great Frontier, particularly the last chapter, and Divided We Stand: The Crisis of a Frontierless Democracy, by the same author.)
Titan's atmosphere is approximately 95% nitrogen. However, in a way that dramatically differs from Earth's own mostly-nitrogen atmosphere, Titan's atmosphere has very little oxygen. Indeed, the remainder of Titan's atmosphere is almost entirely composed of methane--along with small qunatities of other gases, such as ethane. At the extremely cold temperatures that are found at Saturn's great distance from the heat of our Star, Titan's methane and ethane can accumulate on its icy surface to form pools of liquid.
Earth's Moon is enchanting; bewitching. The face of the "man"--that some cultures see etched on its brilliant surface--is really composed of the dark areas of the lunar maria (Latin for "seas"), and the lighter highlands of the Moon's surface. Some cultures tell of other examples of strange images seen on the Moon's lovely disk, such as the "Moon Rabbit".