Which mountain peak is closest to space?

Everest is the highest mountain on Earth. Everybody knows that. But if you want to stand on the spot where you are farthest from the centre of the planet, you need to pack your bags for Ecuador.

The short answer

The summit of Mount Chimborazo, an inactive volcano in Ecuador, is the farthest point on Earth’s surface from the planet’s centre. Its peak sits about 6,384.4 km from the core, roughly 2.1 km farther than Everest’s summit. That is despite Chimborazo being only about 6,263 m above sea level, compared with Everest’s 8,849 m.

The real story

The secret is that Earth is not a perfect ball. Because it spins, it bulges outward slightly at the equator, a bit like a ball of dough flattening as it is twirled. The US National Oceanic and Atmospheric Administration describes the planet as a bit thicker at the equator than at the poles.

That bulge means that sea level itself is farther from the centre of the Earth near the equator than it is further north or south. Chimborazo sits only about one degree south of the equator, right where the bulge is greatest. Everest, by contrast, sits well north of the equator. So even though Everest rises much higher above its local sea level, Chimborazo starts from a much higher launch pad.

Chimborazo has an impressive history of its own. In 1802 the explorer Alexander von Humboldt, with Aimé Bonpland and Carlos Montúfar, tried to climb it and reached about 5,875 m before altitude sickness forced them back. That was higher than any European had recorded at the time. The first confirmed ascent came on 4 January 1880, by the English climber Edward Whymper.

The volcano is capped with glaciers that supply water to the surrounding provinces. For generations, local ice harvesters known as hieleros have cut blocks of its glacial ice to sell in nearby markets. Its last eruption is thought to have happened around 550 AD.

Why people get it wrong

Mountain heights are almost always quoted as height above sea level, and by that measure Everest wins easily. It is a fair and useful measure, so the idea that Everest is the top of the world sticks.

The catch is that sea level is not the same distance from the centre everywhere. Most of us picture Earth as a perfect sphere, so we never think about the equatorial bulge. Change the question from how high above the sea to how far from the middle, and the crown quietly moves to a snow-capped volcano in the Andes. For good measure, there is a third contender too: measured from its base on the ocean floor, Hawaii’s Mauna Kea is the tallest mountain of all.

“Everest gets the fame, Chimborazo gets the view. It’s all about where you start, mate.”