1. The problem statement, all variables and given/known data Two momentarily coincident observers approach a small and distant object. One measures the object to be twice as large as the other's measurement. Find their relative velocity. 2. Relevant equations Lorentz Transforms [itex] L/L_0 = \sqrt(1 - \beta^2) [/itex] 3. The attempt at a solution I tried using the length contraction formula, but it seems way too easy... I thought length contraction is only perceived in the direction of motion. So if we are approaching the object, how can we see any length contraction between the two reference frames? It just seems too easy for an assignment question, and my intuition is usually right. If it is, can you explain to me the flaw in my reasoning? Thanks for your time!