Relativistic time dilation is a well-established consequence of special relativity where time passes more slowly for a moving traveler compared to a stationary observer, effectively reducing the elapsed proper time for interstellar journeys.
The claim is a fundamental, well-known consequence of special relativity (time dilation reduces proper travel time for high-speed travelers). Because it is a basic consequence of established physical theory, it is common knowledge, though paper [8] directly discusses time dilation as a constraint on interstellar expansion.