why?

why do we concentrate so hard on exploring the stars when we haven't even mastered the seas? there is so much down there. so much history. so many tombs. so much unknown. shouldn't we learn to understand, and to save, our own planet, before heading out exploring others? how much money have we spent sending people to the moon, or on the mars probe, or on probes that were sent decades ago, and still haven't reached their destination?
this doesn't make any sense to me.