50 points! why is the ocean harder to explore than outer space, besides the water pressure? : d

Going that deep into the water it can get very hot in the submarine  , whether you believe it or not , it also causes problems when you come back to the surface. The gravity is not the same under water as it is on land . 

In some parts of the ocean the Carbon levels are really high.

In the ocean there are many unknown species and we do not actually know what is down there or what could attack us.

Although we can make lots of forms of light , down in the ocean it is very dark so we can't see basically anything , unless there is a fish that can glo , in the ocean there are many of those .

Also we do not "yet" have a way for gas of a fan powered sub to run for multiple hours
 ( months or days)

I hope this helps

Based on precise facts, scientists have only studied 1% of the Ocean. Imagine that. Why is this so?

This is on the grounds that investigating the seas is more troublesome than investigating the Moon and space. It's genuinely simple to construct a little spaceship to hold weight. The world is full of water. About 70%. So imagine going deep down into the water and exploring all parts of the globe. Scientists haven't created a good equipment to dive deep down into the ocean.