How do find out about something you can't see? The world of particle physics has been uncovered by scientific discoveries over the past century. These particles are too small to be seen by the naked eye. Scientists over many centuries have been creating devices to see things far away such as telescopes as well as ever more powerful microscopes. Today, large particle accelerators can create very energetic particles and scientists can watch these particles decay using complicated detectors. People throughout the millenia have always used the methods available to them to observe the universe.