NASA's "Fundamental Physics in Space" program uses the special "microgravity" conditions of space to test out new ideas about the laws of nature.
Scientists working on these questions are doing some very strange things! In one set of experiments, they will be testing the most accurate clocks ever made.
Like the moving balls of your Newtonian Physics Machine, the atoms and molecules that make up all matter are moving constantly. The faster the atoms in a material are moving, the hotter it is.
Scientists have found a way to super-cool atoms by slowing them down using laser beams. Lasers are a particular kind of "well-organized" light. The light acts kind of like very fast moving particles with . . . you guessed it . . . momentum! The light particles slow down the atoms that come at them from the opposite direction. If the lasers are pointing toward the same spot from several different directions, the atoms can't go much of anywhere.
Once the atoms are moving very slowly, it is much easier to use another kind of light, called microwaves, to measure the time it takes for the atom to go from one state to another. This time is so tiny, yet so constant, that if we can learn to measure it, we will be able to make clocks that are accurate to .000000000000001, or one-quadrillionth of a second!
For a couple of reasons, these experiments need to be done in space. They will be done on the International Space Station. In orbit around Earth, the Space Station and everything in it are in free fall, so the atoms in the experiments will not be disturbed by the effects of gravity. Also, the pull of Earth's gravity really is less the farther from Earth one goes. As you will see, this fact is an important part of these experiments.
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