This seems like an easy question. It is at the top of Mount Everest, of course. But is it that simple? It depends on how you define highest. If you mean the height above sea level, then yes, that is the correct answer. But the Earth is not a perfect sphere. It bulges at the equator, making it what we call an oblate spheroid. So if we define tallest by the distance from the center of the Earth, then we have to also take into account the fact that sea level near the equator is ‘higher’ than at points away from the equator.
If that is taken into account, then the highest point becomes the top of Mount Chimborazo in Ecuador, even though it is just 20,500 feet above sea level, compared to the 29,035 feet above sea level of Everest, though there is disagreement about the exact values depending on how it is measured and the shifts due to plate tectonics.
The Himalayan mountain is actually beaten by Chimborazo, in Ecuador. But Everest still wins on the traditional metrics: it’s nearly 9,000m above sea level, thousands more than any of its closest rivals.
But it’s not actually the furthest up, or the closest to space. Ecuador’s mountain tops it on that measure, and it’s all because of the Earth’s funny shape.
Everest only wins when measured from sea level. But if instead you measure out from the centre of the Earth, Chimborazo wins easily – and Everest wouldn’t even get into the top 20 mountains.
This is a highly political issue because of the tourism benefits that come along with bragging rights. Also apparently Chimborazo is much easier to climb than Everest and thus does not have the same cachet, and so I do not expect Everest’s fame to be diminished.
I’m not going climbing on either one….
Once on a family camping trip, I tried to climb to the top of a 14,000 foot mountain (starting from the highway pass a couple hundred feet lower). I couldn’t make it. Just plain ran out of breath so I had to stop after every couple steps until I just couldn’t go on.
Of course, I wasn’t acclimated at all, being a visitor from the lowlands. Worse, I had injured my hand a day or two before, and had lost a good bit of blood in the process.
All of which makes me extra impressed by the (crazy) people who summit on Everest without oxygen. Talk about pushing the envelope!
Rob Grigjanis says
The height of…silliness. The natural global definition of height would be relative to a surface of equipotential, which is what the mean sea level is.
Since the Kármán line is defined relative to sea level, this is nonsense.
Tabby Lavalamp says
What is the highest point on Earth?
Canada on July 1st.
False. Laughably, easily verifiably false. There are fourteen summits above 8000m. The difference between Everest and its closest rival is 237m, not “thousands”. It’s still quite a margin, but that error is a bit baffling when it’s so easy to check.
Marcus Ranum says
Doesn’t “sea level” bulge with rotation and tides? So ‘which sea level?’ comes to mind.
Rob Grigjanis says
Marcus @6: For mean sea level, tides are ignored, but rotation isn’t. That’s what determines the shape of the Earth’s surface, closely approximated by the reference ellipsoid, and more closely approximated by the geoid.
I am unable to find it right now, but I have a book by Isaac Asimov where he devoted an entire chapter to this question (and the opposite -- what is the lowest point on earth?)
My students love this one:
What is the tallest mountain on Earth?
The island of Hawaii. When measured from summit to base, Hawaii is taller than Everest or K2 when those mountains are measure in the same way.
By the way, I seem to recall that sometime in the ’70s there was a laser measurement from an orbiting satellite using reflectors on both K2 and Everest and K2 came out slightly higher. Does anyone know if those measurements are still valid?
Colorado after Prop 64!
Rob Grigjanis says
hyphenman @8: I think the K2 story was an April Fools joke.
Emory K. says
“Chimborazo is much easier to climb.”
Not when it’s erupting.