Underneath Antarctica

Dear Dr. Science, Underneath Antarctica, is there land or ocean?

———- from Emily Secrest of Mill Valley, CA

Neither. Antarctica itself is a gelatinous mass frozen into near solidity. Underneath it, a hollow tunnel descends through the very center of the Earth and beyond it, all the way to the Arctic, which is simply an immense iceberg floating haphazardly somewhere north of Canada. Flying saucers routinely use this tunnel as a sort of terrestrial dumb waiter to slip from one end of the globe to the other, thereby confusing the producers of the X Files and its many imitators.