Space is infinite and out of reach, while the oceans are finite and limited to our planet. Nautical exploration is as old as humans. There were sailors and sea merchants mentioned in the Bible, and maritime travel and commerce was common during the ancient period, as the Romans and Greeks both took to the seas to explore. Space exploration is much newer, yet, it seems scientists have made more progress. In space, we can see out great distances, and using powerful telescopes scientists can make discoveries about the vast universe around our solar systems because they are both endless we cant go to the bottom of the ocean because we would freeze to death and we can't go to the end of space because the space ship would explode so we don't no what is at the end of space or what is at the bottom of the ocean they both hold many mysteries that's why we cant explain aliens UFOs black holes sea monsters mermaids city of Atlantis because we don't no what is on the other end and we may never know.