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What is the highest point on Earth as measured from Earth's center?

oceanservice.noaa.gov

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Re: What is the highest point on Earth as measured from Earth's center?

#11

Post by jake-low »

SilasX wrote: post #2

>You may be surprised to learn that Everest is not the tallest mountain on Earth, either. That honor belongs to Mauna Kea, a volcano on the Big Island of Hawaii. Mauna Kea originates deep beneath the Pacific Ocean, and rises more than 33,500 feet from base to peak. Can someone explain this? How do you differentiate "the mountain" from "the rest of the earth that it comes out of"? (Side note: the issue of "tallest mou…

The article is likely referring to the estimated dry prominence of Mauna Kea. Topographic prominence [1] measures the height of a peak relative to its lowest surrounding contour line (that doesn't also contain another, taller peak). Usually the ocean's surface is considered "flat ground" when computing this measure (called a "wet prominence"), but one can alternatively imagine the Earth to have no water, and compute a "dry prominence" that permits the lowest surrounding contour line to be below sea level.

[1]: https://en.wikipedia.org/wiki/Topographic_prominence

The above Wikipedia article specifically mentions the dry prominence of Mauna Kea, estimating it to be 9330m which is taller than Everest's conventional height of 8848m. However, an apples-to-apples comparison would use the dry prominence of Everest too, which is the distance from the bottom of the Challenger Deep (-10,911m) to the summit. This would make Mauna Kea the second tallest mountain by topographic prominence if the Earth had no oceans.

Re: What is the highest point on Earth as measured from Earth's center?

#13

Post by ashtonbaker »

SilasX wrote: post #2

>You may be surprised to learn that Everest is not the tallest mountain on Earth, either. That honor belongs to Mauna Kea, a volcano on the Big Island of Hawaii. Mauna Kea originates deep beneath the Pacific Ocean, and rises more than 33,500 feet from base to peak. Can someone explain this? How do you differentiate "the mountain" from "the rest of the earth that it comes out of"? (Side note: the issue of "tallest mou…

Yeah that has always seemed a bit jumbled to me. It's not clear to me why that point, 33,500 feet below the peak of Mauna Kea, is appropriate to use as a basis of measurement for the mountain. And why not a lower point? And why can that point not be used to measure the height of Mount Everest as well?

Anyway, I think what you're asking can usually be described by the concept of Topographic Prominence[1], one definition of which is "the height of the peak’s summit above the lowest contour line encircling it but containing no higher summit"

[1] https://en.wikipedia.org/wiki/Topographic_prominence

Re: What is the highest point on Earth as measured from Earth's center?

#15

Post by simcop2387 »

Which center? The centroid of the spheroid that is the earth (i.e. the point that's as close to equidistant from all points as possible)? The center of mass? The gravitational center (I think this would be the same as the center of mass, but i'm not positive)?

I'd be curious how the different centers change the results.

Re: What is the highest point on Earth as measured from Earth's center?

#16

Post by carleverett »

magduf wrote: post #3
SilasX wrote: post #2

>You may be surprised to learn that Everest is not the tallest mountain on Earth, either. That honor belongs to Mauna Kea, a volcano on the Big Island of Hawaii. Mauna Kea originates deep beneath the Pacific Ocean, and rises more than 33,500 feet from base to peak. Can someone explain this? How do you differentiate "the mountain" from "the rest of the earth that it comes out of"? (Side note: the issue of "tallest mou…

When comparing the actual height of a mountain, they're measured from their base (which is whatever elevation the ground they sit on is) to their peak, rather than just looking at their peak altitude. This is how you compare mountains on other planets, and why Mons Olympus on Mars is the tallest mountain in the solar system. For Mauna Kea, the mountain is taller than it looks because its base sits at the bottom of th…

I had to look this up, but apparently "sea level" on Mars (called "topographic datum") is decided using the average elevation near the equator.

http://passporttoknowledge.com/lfm/ask/terrain-geo/Determini...

Re: What is the highest point on Earth as measured from Earth's center?

#17

Post by SilasX »

jake-low wrote: post #11
SilasX wrote: post #2

>You may be surprised to learn that Everest is not the tallest mountain on Earth, either. That honor belongs to Mauna Kea, a volcano on the Big Island of Hawaii. Mauna Kea originates deep beneath the Pacific Ocean, and rises more than 33,500 feet from base to peak. Can someone explain this? How do you differentiate "the mountain" from "the rest of the earth that it comes out of"? (Side note: the issue of "tallest mou…

The article is likely referring to the estimated dry prominence of Mauna Kea. Topographic prominence [1] measures the height of a peak relative to its lowest surrounding contour line (that doesn't also contain another, taller peak). Usually the ocean's surface is considered "flat ground" when computing this measure (called a "wet prominence"), but one can alternatively imagine the Earth to have no water, and compute…

Thank you, that's the kind of concept I was looking for.

Re: What is the highest point on Earth as measured from Earth's center?

#20

Post by spurgu »

simcop2387 wrote: post #15

Which center? The centroid of the spheroid that is the earth (i.e. the point that's as close to equidistant from all points as possible)? The center of mass? The gravitational center (I think this would be the same as the center of mass, but i'm not positive)? I'd be curious how the different centers change the results.

I would assume all of these (add center of volume) to be quite close to each other for all practical intents and purposes, given how smooth Earth's surface is in the big picture:

https://what-if.xkcd.com/46/

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