Mt. Semantics

Mount Everest may be the tallest mountain on Earth, but that's only if you're measuring from sea level. Thanks to the curvature of the planet, Mount Chimborazo in Ecuador is the highest if you're measuring from the center of the Earth. In fact, by this system, Everest comes in fifth. (Via Chris Pasco-Pranger)

Maggie Koerth-Baker is the science editor at BoingBoing.net. She writes a monthly column for The New York Times Magazine and is the author of Before the Lights Go Out, a book about electricity, infrastructure, and the future of energy. You can find Maggie on Twitter and Facebook.

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adamnvillani

Mauna Kea is not on Oahu. It is on the Island of Hawaii, aka “the Big Island.” Hawaii is the largest and tallest of the Hawaiian Islands, but it is not the most populous. Hawaii includes the towns of Hilo and Kailua-Kona. Oahu is the most populous of the Hawaiian Islands and includes the city of Honolulu, but the mountains on it are not particularly tall when compared with Haleakala (on Maui), Mauna Loa, or Mauna Kea.
MrScience

I’d personally prefer to know which mountain is closest to space. It’s rather pointless, IMHO, to be the “tallest” if you’re right next to sea level… or if you’re covered by twice as much air as a mountain a few degrees north and just as tall…
- dculberson
  
  Exactly; highest to me implies closest to the KÃ¡rmÃ¡n line, the edge of space. I don’t know if Everest or Chimborazo is closer to that, but to me whatever mountain is closest to space is the highest. Of course, that’s my own personal arbitrary definition.
Frank W

Last thing I heard, the planet is mostly a drop of liquid material with a thin coating of solids on top. It makes a full rotation once every twenty-four hours,and because of that, the sphere is ever so slightly flattened. The pole-to-pole distance is shorter than the equatorial diameter. No wonder the tallest mountain sits on the equator if you choose to measure from the centre of the planet.
- Nelson.C
  
  Actually, to be pedantic, only about an eighth by volume is liquid: the outer core. The inner core is solid, as is the mantle. The mantle can be said to be fluid, but as it circulates only about as fast as your fingernails grow, it’s still solid.
Not a Doktor

Now thanks to the internet being everywhere and our post-information scarcity society everything is uncertain and pendantic assholes (think they) rule every conversation.
- djn
  
  Or, to be positive: We now get a larger concentration of possibly relevant facts on any issue than anyone before. I love this, since I find extra information of that sort quite interesting. :)
- IsolatedGestalt
  
  …pendantic assholes…
  
  Must…not…correct…(lest I prove them right…)
  - arkizzle / Moderator
    
    IsolatedGestalt,
    
    That was a big step in your development. Well done, you’re really making progress now.
    
    Lollipop?
Halloween Jack

Doesn’t distance from sea level correlate to the thinness of the air, which really determines how difficult it is to climb at altitude, which is sort of the whole point? Chimborazo isn’t as high as Camp II, or Advanced Base Camp, on Everest.
- Lobster
  
  Difficulty is the whole point if you’re a climber. I’m not. I’m more curious about bigness and mountainness. Besides, if “tallness” was just a matter of how hard it was to climb couldn’t you take a 20-foot pile of loose broken glass, cover it with oil, set it on fire, and call it the tallest mountain in the world?
Anonymous

So it’s not Mauna Kea?

http://en.wikipedia.org/wiki/Mauna_Kea

“The peak of Mauna Kea is 13,803 feet (4,207 m) above mean sea level, about 100 feet (30 m) taller than neighboring Mauna Loa and about 30,000 feet (9,100 m) above its base on the floor of the Pacific Ocean. By this measurement, Mauna Kea is the world’s tallest mountain, taller than Mount Everest, which is the highest mountain above sea level.”
- Chuck
  
  >So it’s not Mauna Kea?
  
  I’m game for some underwater mountaineering. (Gotta get me one of those old-timey diving suits.)
arkizzle / Moderator

Tangentially related: If the sea levels rise, does Everest (et al.) get shorter?
Jesse in Japan

How tall something is is a matter of the vertical distance from base to top. The base of a mountain is not the center of the earth, it’s the foot of the mountain.

So, the island of Oahu is the tallest mountain on earth.
- Moriarty
  
  How do you measure the “base” of Oahu? And what’s stopping you from saying the “base” of Everest is also on the ocean floor? At least sea level is well defined.
Abby

To be a bit more pedantic, the earth is indeed an oblate spheroid, but only slightly. The implication by the article that the shape of the planet is a *lot* more distorted than it is bugs me.
cniebla

We live on the age of information, so everything that’s labeled “…of the world” belongs to the past age, when people used to learn about everything from encyclopaedias, and so it’s this kind of knowledge is known as “encyclopedic knowledge”. Encyclopedic people (people of age / people with no access to Internet) are really annoying: they only know ONE kind of cultural representation of the world, and they like to defend it like it’s some kind of “cultural heritage” of some “great value”… I feel sorry for them… so little information and so much great appreciation for it….
Anonymous

How does this affect the gravity? Is gravity atop Everest greater or less than Earth’s gravity at the peak of Chimborazo? I assume Chimborazo would have the weakest gravity anywhere above the surface of the Earth. Anyone know?
- Alpinwolf
  
  (partly for the anonymous gravity question, also for all)
  
  (Oh, and to Chuck@12: didja see the Mythbusters’ experiment about those old-timey suits? You don’t wanna end up in the helmet. And I mean *all* of you. ;)
  
  Ah, pedantry, my old friend…
  
  Totally down with the “oblate spheroid” description, but to augment it the globe also qualifies as a “geoid”, implying a certain chunky irregularity. (Not the kind helped by Metamucil.) Google up “geopotential surface” and you’ll find that the roughly (and oblately) spherical surface at which gravity is considered constant does not at all match discrete sea level, or even average sea level.
  
  The question of gravity at the tops of the peaks is quite interesting, and non-trivial. Radius from center alone doesn’t quite do it, since one needs to consider the varying densities of the materials in the crust nearby. For illustration, (and I may be wrong, out of practice), on the summit of two otherwise equivalent peaks, if one is simply the highest spot in the middle of a vast massive mountain range, versus the other being a solitary peak much higher than surrounding terrain, the subjective gravity would be minutely greater on the former.
  
  And then there’s the centrifugal acceleration of being closer to the outermost diameter of the spinning body…
  
  I propose to compare the height of each peak above zero on the local geopotential surface, and factor in the centrifugal acceleration and proximity to the local KÃ¡rmÃ¡n line, in some kind of matrix…
  
  Only then will we be absolutely certain that the debate will never end!
  - Chuck
    
    >(Oh, and to Chuck@12: didja see the Mythbusters’ experiment about those old-timey suits? You don’t wanna end up in the helmet. And I mean *all* of you. ;)
    
    Ooooooh!
    
    Added risk!
    
    I like it. (No I don’t.)
Chuck

But if you measure from the Earth-Moon barycenter, then the tallest mountain is…

DAMN! I don’t know the name of any Moon mountains.
- Moriarty
  
  But if you measure from the Earth-Sun barycenter, then the tallest mountain is constantly changing, but always at exactly midnight (measured by daylight, not time zones) somewhere in the tropics. Unless you include the moon, in which case that’s only true half the time. Or unless you include all bodies in the solar system, in which case it’s some pebble in the outer reaches of the Oort Cloud.
  - Chuck
    
    >Or unless you include all bodies in the solar system, in which case it’s some pebble in the outer reaches of the Oort Cloud.
    
    Now we’re gettin’ the idea. (Space flight: it’s like mountaineering … with lots of big jumps.)
- Nelson.C
  
  Probably the central peak of Daedelus Crater, on the far side of the Moon.
mneptok

Oh no …

I used to think that the 2 meter tall pimple on my ankle was the largest blemish on my body. But since I now have to measure from the soles of my feet instead of skin level, that 1 nanometer zit on my scalp is larger.
schwal

The mistake in this post is confusing highest with tallest. Chimborazo is the highest, Oahu is the tallest.
- mneptok
  
  The mistake in this post is confusing highest with tallest.
  
  I used to make that mistake all the time. “Dude, don’t pass the basketball to Mike! He’s the tallest guy on the team, but he’s totally baked!”
Anonymous

Meh, Mount further out on an oblate spheroid.