Humans have only explored 20% of oceans
We’ve mapped 100% of our oceans at 5 km resolution using satellite radar. If you account for shipping routes and scientific expeditions, we’ve mapped out about 20% of ocean bathymetry with sonar.
So that means we have oceans mapped at about 100 meters resolution which is the same as our surface maps of Venus and Mars.
The other 80%? The reality is that most of our oceans are totally untouched. Even though 70% of Earth is covered by oceans, we know little about our ocean seafloor.
Despite the need to understand ocean CO2 sequestration, nutrient recycling and untapped energy resources, the biggest drawback is the high cost of exploring oceans.