This settling process, called sedimentation, causes layers to form as the metals cool into a solid. In microgravity, sedimentation is reduced, and IML scientists were able to form alloys of metals that are almost impossible to combine on Earth. IML scientists grew larger crystals of proteins and viruses in microgravity than they can on Earth. The larger crystals make it easier for scientists to determine the molecular structure of the proteins and viruses, and this information can be used to design disease-fighting drugs. The force of Earth's gravity extends far into space.
Weight is the force with which a body is attracted to the Earth.
Any object in a state of freefall experiences microgravity, or near weightlessness. An orbiting spacecraft is actually falling around the Earth. The spacecraft's altitude and speed cause its fall to match the curvature of the Earth, so that it never hits the Earth but continually orbits the planet. All objects carried by an orbiting spacecraft are also in a state of freefall.