According to Lorentz, time is always dilated. So think of two twins, Speedo and Goslo. - Goslo stays on Earth and drinks tea. - Speedo gets into a rocket, zooms off into outer space and zooms back. Imagine YOU are Speedo. You zoom off, and when you return to Earth, you find that Goslo is 20 years older than you. Both of you were the same age when you left, but now he's way older. This means he must have aged faster. But how could Goslo appear to age faster, when time is always dilated?!. Discuss this but only consider Speedo's point of view. Because if you are Speedo, what would you see?