Simply, because humanity cannot understand everything. 

Not everything can be explained and not everything has a logic. 

Not everything makes sense.

We do not have many answers. 

Furthermore, because we do not understand and know everything, we still do not have some of the questions that humanity may someday have. 

The information we have is limited, it is not enough.

And the earth goes around, and the universe exists.

And humanity lives.

And life goes on.