If you stand on a California beach and look out at the ocean–imagining where you’d end up if you travel long enough in a straight line–you might guess Japan.
That’s what a simplified map showing what’s across the ocean indicated a few years ago; by latitude, the two places line up. But if you actually went straight, you might not even end up in Asia. Because of jagged coastlines and the fact that the Earth is round, the opposite point from many coasts is in a completely unexpected place.
If you sailed straight from certain points in California, you could end up in Australia, Antartica, and even Africa.
“To me the most interesting thing is just an overall surprise at how far a straight line can go without hitting land, like from the U.S. East Coast to Australia or Asia,” says Andy Woodruff, who designed a new set of maps showing what’s really straight ahead from every coast. “Even as someone who works with maps for a living, I hadn’t realized it was possible. Most of the maps we see every day just don’t provide a good sense of the true geometry of the Earth.”
Woodruff calculated the direction from points along each coastline–leaving out those that pointed back at the same continent–and then centered each point in the same type of map that’s often used to calculate flight distances.
“On that kind of map, a straight line from the center point is a ‘straight’ line on the globe, i.e. a great circle,” he says. “So then I could draw a straight line in the right direction for each point, then find where it hit land.” Then he converted the data back into pretty–and fascinating–maps that show what’s across from every continent.