Presentation: Tom Lugar will present "Special and General Theory of Relativity Concepts of Time Dilation (Twin Paradox) and Distance/Length Contraction; How not to Understand It".  Tom will discuss the concept of time dilation using the example of the Twin Paradox which involves twins, one of whom remains on Earth while the other twin travels in a spaceship close to the speed of light to a distant star system. On return to Earth, the astronaut twin will be much younger than the twin who stayed on Earth. Time dilation must be taken into account for our GPS systems to operate accurately. Misconceptions explaining the concepts in articles and books for the general public and even in college science textbooks for non-science majors will be debunked.