Oh Jacki, this is a hard question. . . If i have to choose, and can't do both i'd choose deep sea diver. They have discovered everything the current technology has made possible to discover in space. But the ocean is still mostly undiscovered. Sure, space is way bigger than the oceans but technology makes it possible to see greater distances than you can in the ocean. In the ocean you have to physically cover ground yourself. I don't believe in aliens, i do however believe in strange sea creatures.