You specify the accuracy you need. Let's say, 1 millimeter. (9.3e10 light years) / (0.001 meter) = 8.79 × 10^29 log2(8.79 × 10^29) = 99.471 So you need 100 b

You specify the accuracy you need. Let's say, 1 millimeter. (9.3e10 light years) / (0.001 meter) = 8.79 × 10^29 log2(8.79 × 10^29) = 99.471 So you need 100 bits to represent each coordinate at that precision.