Why is New York almost as far away from Berlin as the center of the Earth?

Here’s a number that seems impossible at first glance.

From Berlin to the center of the Earth: about 6,371 kilometers. That’s the Earth’s mean radius—the distance from the ground beneath your feet to the molten core of our planet.

From Berlin to New York: about 6,381 kilometers.

The difference between “drilling halfway through the Earth” and “flying across the Atlantic”: ten kilometers.

Why this is so hard to believe

Our brains are excellent at estimating horizontal distances—at least roughly. We drive these distances, we walk them, and we see them on maps. A transatlantic flight takes nine hours and feels correspondingly long.

Vertical distances, on the other hand, are almost unimaginable to us. We live on the surface of a planet, not inside it. The journey down—through rock, the mantle, the outer and inner cores—is something no human has ever traveled or will ever travel. We have no intuitive reference for it.

Yet this journey, in plain kilometers, is barely longer than a long-haul flight.

What this says about Earth

Earth feels huge. It is—compared to everything we know in our daily lives. But on a cosmic scale, it is a rather small rocky sphere. Its diameter at the equator is just under 12,756 kilometers. That is less than the distance between Sydney and London. Our entire biosphere—the thin layer in which all life exists—is comparable, on a globe, to the condensation from a breath on a soccer ball.

On your next long-haul flight, when you look down into the clouds or at the dark earth, you’re traveling just as far as it would be to the center of the Earth. Only horizontally.