GMT complex take Literature and history are a bit ambiguous. Another one is millisecs but this is very rare. Theory of Relativity The Special and General theories of Relativity are taken into account by GPS receivers found in planes, cars and mobile phones and Earth-orbiting satellites to synchronize their time within a nanosecond range. This is illustrated in the next code listing. Therefore the maximum difference between 2 local times on Earth is 26 hours. The formal one would be ms. The next code listing demonstrates these classical approaches.