Universe is expanding. We can't travel the whole space it's just impossible. And so scary too at the same time. And we live in vacuum is another scary.
Even if Universe sometime in future stop expansion then also we can't travel because there are too many variables
1) Our life span is short
2) Radiation
3) Even without expansion, universe is still so huge then we need thousands of years just to travel through milky way with speed of light ( speed which we can never achieve)
I am not scared of this fact that we are so fuckn alone.
I am scared that I know I will never learn how universe began and what lies before Big Bang.