Racing high over the Sahara at 5 miles per second, protected from the desert’s parched endlessness and soaking in its sere beauty, I saw Khartoum, the city where the White and Blue Nile rivers meet. I turned my head left and followed the river downstream to Cairo and the Mediterranean. Twisting weightlessly back to my right, I could pick out sunlight glinting off the waters of Lake Tana and Lake Victoria, the Nile’s headwaters. Explorers from the early Greeks to Queen Victoria’s David Livingstone had toiled and failed to find what I could see at a glance. Impressive on its own—even more so since I had been over Winnipeg, on the edge of the Canadian prairies, just 20 minutes earlier.
Circling Earth so fast makes you think. When you look out the window of a spaceship, you see entire countries, vast swaths of continents. One turn of the head covers what once took thousands of years to traverse at ground level. Historians and archaeologists estimate that human beings started migrating from Africa to Asia about 70,000 years ago, and to Australia 20,000 years after that. We went to the New World of the Americas about 30,000 years ago. All told, from the first dissatisfied teenager’s steps away from home, it took about 50,000 years to walk to the far corners of the planet.
Technology helped us pick up the pace. By the 1870s, new railways across the US and India and the opening of the Suez Canal made it seem completely plausible that the fictional Phileas Fogg and his valet could circle the world in 80 days. In 1911, Roald Amundsen reached the farthest end of Earth and stood atop the South Pole; 50 years later, the Soviet Union sent Yuri Gagarin around that same world in a little more than 80 minutes. And since November 2000, astronauts on the International Space Station have circled our planet 16 times a day—that’s about 75,000 times around and counting.