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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?

#21

Post by wallace_f »

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…

>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

What? This does not make sense, if I am not mistaken? Topographic prominence would place Mauna Kea as the tallest (highest peak from base contour line), but it would certainly not be the second highest above the Challenger Deep... And the Challenger Deep is not the base contour line of any mountain..?

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

#22

Post by vesinisa »

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…

Yes, that is correct. At almost 20,000 km, the dry prominence of Everest is by definition the maximum possible on Earth. You only get to claim Kea more prominent if you use a different standard to measure it!

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

#23

Post by njarboe »

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…

From your link, the lower elevation of a dry prominence of Everest would be the lowest contour that encircles Everest. That won't be nearly as deep as Challenger Deep but a quick google search does not find the correct dry prominence for me.

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

#24

Post by vesinisa »

njarboe wrote: post #23
jake-low wrote: post #11

Earlier quoted context omitted.

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…

From your link, the lower elevation of a dry prominence of Everest would be the lowest contour that encircles Everest. That won't be nearly as deep as Challenger Deep but a quick google search does not find the correct dry prominence for me.

The lowest bottom of the Challenger Deep encircles the Everest. Think of the "outside" of the circle being the deepest point, and the "inside" of the circle being all rest of the Earth.

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

#25

Post by thefifthsetpin »

vesinisa wrote: post #22
jake-low wrote: post #11

Earlier quoted context omitted.

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…

Yes, that is correct. At almost 20,000 km, the dry prominence of Everest is by definition the maximum possible on Earth. You only get to claim Kea more prominent if you use a different standard to measure it!

I'm not seeing why that is true. If one were to imagine a deep moat around Kea, wouldn't that increase its prominence w/out impacting that of Everest? Or are you suggesting that Everest's dry prominence would be measured from whatever the deepest point on Earth is? Or something else?

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

#26

Post by njarboe »

vesinisa wrote: post #24
njarboe wrote: post #23

Earlier quoted context omitted.

From your link, the lower elevation of a dry prominence of Everest would be the lowest contour that encircles Everest. That won't be nearly as deep as Challenger Deep but a quick google search does not find the correct dry prominence for me.

The lowest bottom of the Challenger Deep encircles the Everest. Think of the "outside" of the circle being the deepest point, and the "inside" of the circle being all rest of the Earth.

Got me on that one.

Seems to me "topographic prominence" is useful for people talking about peaks in a mountain range. Not so much when the spherical shape of the Earth starts to be significant.

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

#28

Post by SilasX »

vesinisa wrote: post #24
njarboe wrote: post #23

Earlier quoted context omitted.

From your link, the lower elevation of a dry prominence of Everest would be the lowest contour that encircles Everest. That won't be nearly as deep as Challenger Deep but a quick google search does not find the correct dry prominence for me.

The lowest bottom of the Challenger Deep encircles the Everest. Think of the "outside" of the circle being the deepest point, and the "inside" of the circle being all rest of the Earth.

Reminds me of the joke where the mathematician is told to use a fixed length of fencing to enclose the biggest area possible and builds a tiny corral and stands inside and says "I define myself as outside the corral".

(Legit point on your part, though.)

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

#29

Post by jake-low »

wallace_f wrote: post #21
jake-low wrote: post #11

Earlier quoted context omitted.

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…

>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 What? This does not make sense, if I am not mistaken? Topographic prominence would place Mauna Kea as the tallest (highest peak from base co…

Think about it this way: imagine standing at the bottom of the Challenger Deep. Draw a small circle around yourself on the ocean floor. Now step outside the circle. Because you're standing on a spherical object (Earth), the area outside your circle isn't infinite like it would be on a plane. It's another finite region, which covers almost the entire Earth, and contains both yourself (standing just beside the lowest point of the Challenger Deep) and also the peak of Mount Everest. Therefore the circle is a base contour line for Everest, and Everest's wet prominence can be measured from the circle.

However, this same contour line cannot be used for the wet prominence measure of Mauna Kea, since it contains every mountain on Earth, many of which are taller. Mauna Kea's lowest contour line that doesn't contain another taller mountain would probably enclose a sizeable portion of the floor of the Pacific Ocean, but wouldn't include the Andes, Japan, or the Sierra Nevada, since those peaks are taller. The contour line would therefore be deep below the ocean surface, but not as deep as the Challenger Deep.

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