If light takes 1 year to reach a destination, and it takes a ship 2 years to reach the same destination, how fast is the ship going? Is a question like this possible to answer without more information? I'm looking at the Lorentz transformations, and am finding all sorts of ways to be confused. The equations are undefined when v = c, and distances change in the moving frame depending on the values of v. What is the distance for between points for light? Does this question have meaning?