I just started thinking about it. Why is space exploration even that necessary? They're spending so much money on it when we have so much problems in our own planet..
Solving problems for the sake of solving them yields great joy (and unexpected benefits). You don't need to have a stable job to solve a sudoku or crossword once in a while.
If not for space exploration, we'd not have soo many technologies. We'd not have pushed so many boundaries that a lot of advances would have happened way too late than we did.