https://youtu.be/sNhhvQGsMEc?t=57s


They always make the same mistake when talking about high-speed travel.
Really fast spaceships would appear to take billions of years to reach another galaxy, for observers stuck on Earth. However, the occupants in a relativistic spaceship could experience something completely different: their destination arrives at the blink of an eye, and it (the galaxy) undergoes accelerated ageing, while the passengers stay young.

It seems like a pretty bad side-effect of interstellar travel when everything else gets old around you. And every journey is a one-way trip into the unknown.