cosmological-models

In this introduction, Charles Sheffield outlines his strict definition of hard science fiction, emphasizing the necessity of scientifically accurate and plausible elements, particularly adhering to the speed of light as an absolute limit. He discusses how evolving scientific understanding, especially regarding cosmology and the universe's expansion, has necessitated significant revisions to his work, and reflects on the potential impact of future discoveries such as faster-than-light travel on his storytelling approach.