Eli5: How are we so confident that cartographers know the exact shape of Antarctica underneath its ice? When in our history were we able to know that the Artic and Antarctica were made up entirely differently?

Question

Eli5: How are we so confident that cartographers know the exact shape of Antarctica underneath its ice? When in our history were we able to know that the Artic and Antarctica were made up entirely differently?

In: Earth Science

Answer 1

I don’t know when and how they found the exact shape, but small coastal parts of Antarctica are free of ice in summer, and unlike the Arctic there are mountains in Antarctica.

And we don’t really know the exact shape actually, we can only estimate where the “coast” is in some parts.

Answer 2

Just like you can look at something a long ways away and see what it looks like even though there is air in the way. Satellites can use different types of sensors (eyes) to “see” in a way that makes the ice as invisible to them as air is to us.