Science Puzzle
Which Mountain Top Is Furthest from Earth’s Centre?
Mount Everest is the highest mountain above sea level, at 8,849 metres. K2 comes second at 8,611 metres. Chimborazo, a volcano in Ecuador, is only 6,263 metres high, but it stands almost on the equator.
Which of the three summits is furthest from the centre of the Earth?
The Answer
Chimborazo. Its summit is about 6,384 kilometres from the centre of the Earth, roughly 2 kilometres further out than the top of Everest, because the Earth bulges at the equator.
Earth spins once a day, and the spin makes it bulge around its middle. Sea level at the equator is about 21 kilometres further from the centre than sea level at the poles. Chimborazo starts from that bulge. Everest is 28 degrees north and K2 is 36 degrees north, both on less bulging parts of the planet, so their extra height above sea level isn't enough to make up the difference.
"Highest mountain" depends on how you measure. Above sea level, it's Everest. From its own base to its summit, much of it under the sea, it's Mauna Kea in Hawaii. Furthest from the centre of the Earth, it's Chimborazo, which makes its summit the closest you can stand to outer space.
The principle: The equatorial bulge. Earth's spin makes it bulge at the equator, so places near the equator sit further from Earth's centre than places at the same height further north or south.