Weight is caused by gravity and objects in space are never free of gravity. Objects orbiting the Earth are actually being pulled toward the Earth by gravity. Since these objects are falling at the same rate, they appear to be floating. This accepted value for the density of water is measured at 4 o C, when water is most dense. Our galaxy has a spiral shape.
Earth is located near the end of an arm at the outer edge of the Milky Way galaxy.
Our solar system has 9 known planets.