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Sounds like The Slow Path. In regards to the object itself, Traveling Landmass or Orbital Bombardment might cover it, depending on the context of whether it's an inhabited island or an unidentified ship with heavy weaponry respectively.
Silver and gold, silver and gold
Just want to note, The Slow Path is specifically about when time travel is involved, that Alice (a time traveler) can hop into her time machine, flip a switch, and advance to the year 2050, while Bob (not a time traveler) wants to meet Alice in 2050 but must take The Slow Path by letting time pass at the normal rate. It needs that "slow compared to time travel" element rather than just "waiting a long time".
^ I kind of figured, but I took the hypothetical as involving an object that's "suited" for time travel even if people don't (want to) use it. Like how in Stargate: Continuum they each have a preferred window of time travel, but don't tell each other about it because they can see Ba'al's death coming.
Only other thing I can think of is Medieval Stasis, but that's about society's control over tech rather than control over object travel.
Edited by Coachpill Silver and gold, silver and gold
As the title says itself. What is the trope where an object has been travelling for a long time, like the real-life Voyager 1 and 2 space probes?