How can we conclude that “Challenger Deep” is the deepest part of the ocean. Does that mean we have explored all parts of the ocean?

Question

How can we conclude that “Challenger Deep” is the deepest part of the ocean. Does that mean we have explored all parts of the ocean?

In: 15

Answer 1

Scientists have used downward-facing radar for decades, doing a rough mapping of the ocean floor. So, they have a ‘general’ idea of what the deepest parts of the ocean are.