Here was a sense of being utterly alone in what are perhaps the earth’s most remote reaches: the Arctic Ocean, at the edge of the summer pack ice. I thought I had sensed something like this before, on passages crossing the world’s other oceans, but this seemed to be of a greater — and lonelier — scale. The only human sound was the creak of our boom. The feeling that that was it, for many, many miles, was palpable. All around was a watery, icy horizon. I heard the crackling of melting growlers and a tinkling as our bow pushed icy flakes aside. Clouds gathered overhead and cast the sea in a silver pallor. The ocean heaved in a long, steady swell, lifting and dropping the white floes. Atop the swell, I saw an unbroken line of chaotic ice, parts of it pushed up into strange looming forms after a winter of grinding pressure and wind. At first glance it looked like landfall, but of course it wasn’t: It was the polar sea itself, stretching for miles across the top of the world and touching again on the shores of Siberia.