I do not understand the difference between separation in space and separation in time. Could someone please explain the following positions to me? I would be very thankful and appreciative if so. Position of event 1: Separation in time (lightyears) = 20. Separation in space (lightyears) = 0 I think of light years as a measure of distance. So if separation in space is zero, then that must be my exact location, so how can it be 20 light years away in time? Position of event 2: Separation in time = 25. Separation in space = 15. If I think of light years as distance, how can the two be different? Position of event 3: Separation in time = 52. Separation in space = 48. Same confusion as #2. Position of event 4: Separation in time = 101. Separation in space = 99. Many thanks!