Time traveling

PBS Nova
How could we use time to measure time? We are stuck in it, each of us time travels into the future, one year, every year. None of us to any significant precision does otherwise. If we could travel close to the speed of light, then we could travel further into the future in a given amount of time. It is one of those concepts that is profoundly resistant to a simple definition, said Carl Sagan, the astronomer, Pulitzer Prize-winning author, and legendary popularizer of science.