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.
Titan has three large seas. However, the seas of Titan are not filled with water, but are filled instead with swirling liquid hydrocarbons. All three of Titan's exotic seas are close to its north pole, and they are surrounded by many smaller hydrocarbon-filled lakes in the northern hemisphere. Until 2004, no spacecraft had visited Saturn for more than twenty years. Pioneer 11 took the very first close-up images of Saturn when it flew past in 1979. After that flyby, Voyager 1 had its rendezvous about a year later, and in August 1981 Voyager 2 had its brief, but glorious, encounter. Nearly a quarter of a century then passed before new high-resolution images of this beautiful, ringed planet were beamed back to Earth. When President John F. Kennedy stated in 1960's that the US will go to the moon in less than a decade, most people were extremely skeptical. The reason for this stemmed from the fact that USSR had shown more accomplishments in the space race after the launch of Sputnik, which was the world's first satellite. Naturally, the skepticism was unfounded, since the US put all of its efforts in to the Moon program as billions of dollars were put in to it. The development of the Saturn rocket as well as the development of the Apollo lunar module took less than a decade, since the whole heart and soul of the American public was put into the Lunar program. Even the various tragedies such as the loss of Astronauts in the Apollo fire tragedy didn't deter the public. As a result, 1969 was an important year in the human history as mankind stepped into Lunar soil for the first time. Sadly, the program was discontinued and since the 1970's, no man has even stepped into the Lunar soil ever again.