NASA G-Force



Earth's mysterious large Moon is our nearest neighbor in space, dominating our clear night sky with its beguiling and bewitching cold golden glow. Earth's Moon is the only body beyond our planet that we have visited, leaving our footprints embedded in its alien dust. Despite its close proximity to our planet, our mysterious Moon has still managed to keep some ancient secrets from us very well. However, in October 2014, using data derived from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, a team of planetary scientists announced that they may have solved a lunar mystery almost as old as our Moon itself. The precise chemical composition of these very alien lakes and seas remained unknown until 2014, when Cassini's radar instrument detected Ligeia Mare, now known to be Titan's second-largest hydrocarbon-filled lake. Ligeia Mare is brimming with an abundance of sloshing methane, and this enormous liquid reservoir is approximately the same size as two of Earth's Great Lakes combined--Lake Michigan and Lake Huron. Many planetary scientists think that the seabed of Ligeia Mare may be blanketed with a thick layer of sludge that is composed of organic-rich compounds. The Solar System forms a tiny part of the Milky Way Galaxy, a vast conglomeration of stars and planets. What makes astronomy so thrilling is that despite its size, the Milky Way is not the only galaxy in the universe. There are hundreds of billions of galaxies out there, probably more. The closest galaxy to our own Milky Way is Andromeda. Now, brace yourself for the distance: it is 2.3 million light years away. One of the most exciting phenomena for astronomers is the black hole. It is an area of the universe where the concentration of mass is so massive (no pun intended) that the gravitational pull it generates sucks in everything around it. Everything includes light. Remember that the escape velocity for any object in the universe is the speed required to escape the objects gravitational pull. The escape velocity for the Earth is slightly over 11 kilometers per hour while for the Moon is 2.5 kilometers per second. Well for a black hole, the escape velocity exceeds the speed of light. That is how strong the pull is.