Time Debt is a reference to the amount of standard time that would have passed for a person travelling at speeds approaching and passing light speed, had they remained at standard velocities. For example, travelling via Hawking Drive time progresses roughly 20 times slower; two weeks' "ship-time" travel correspond to roughly one standard year.
Time debt is considered something most people try to avoid, as it can cause problems when family and friends age far more rapidly than their loved ones. This is made clear in Hyperion during the Consul's story "Remembering Siri", where Merin Aspic experiences only 5 years of time while traveling, while Siri experiences over six decades in her home world of Maui-Covenant.
Another example is in "The Priest's tale" where Father Lenar Hoyt narrates his journey to Hyperion to accompany Father Duré. Before accepting the journey, Hoyt laments its time-debt which "would return him to Pacem eight years behind his former classmates in the quest for Vatican careers and missionary postings."
- ↑ The Rise of Endymion. 1997. Chapter 14