So, even though “100,000 light years” means “it will take 100,000 years to travel this distance at the speed of light,” those traveling won’t experience it as 100,000 years, but rather a much shorter time period? How long would the travelers experience that as?
To be clear I’m not talking about “almost light speed,” I’m talking about traveling at exactly the speed of light (ignoring for a moment whether that’s possible).
At exactly the speed of light you would experience no duration at all. But it would take infinite energy to get going that fast, and infinite energy again to stop, and would still take 100,000 years as seen by anybody watching at either end.
To be clear I’m not talking about “almost light speed,” I’m talking about traveling at exactly the speed of light (ignoring for a moment whether that’s possible).