
What is the highest point on Earth as measured from Earth's center? - DoreenMichele
https://oceanservice.noaa.gov/facts/highestpoint.html
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SilasX
>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 mountain", as discussed here, is a great
example of dealing with an ambiguous concept and clarifying it by asking what
you're trying to do with the answer.)

~~~
jake-low
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](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.

~~~
njarboe
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.

~~~
vesinisa
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.

~~~
SilasX
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.)

~~~
starbeast
In Douglas Adams''So Long And Thanks For All The Fish', Wonko the Sane resided
either outside or inside, depending on your point of view, an inside-out house
that he had built as an asylum for the world, after reading the instructions
on a packet of toothpicks.

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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.

~~~
spurgu
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/](https://what-if.xkcd.com/46/)

~~~
Svexav
You would be wrong.

Make the problem simpler by thinking in 2 dimensions. Where's the center of
the United States? There are an infinite number of different answers. Think
about how many different map projections there are.

Now where is the center of the Earth? The point furthest from sea level? The
point furthest from the surface? Do you include mountains, ocean basins, ocean
trenches, etc.? What % of a substance has to be water before it doesn't count
as part of the earth? The point furthest from the edge of the atmosphere? How
do you determine where that is? Or is the center of mass? These are all going
to give you wildly different answers.

Humanities questions cannot be easily solved scientifically.

~~~
dikei
The variation cause by mountain or sea trench is absolutely tiny compared to
the earth diameter, as explained by his xkcd's link.

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krupan
"That makes Chimborazo the closest point on Earth to the stars."

That statement sold me. If I want to be on the top of any mountain now, it's
that one.

~~~
ghaff
It's not an easy mountain but it's of a substantially lower degree of
difficulty than the high Himalayan peaks. It's harder than the lower Ecuador
volcanoes for reasons of elevation and other factors and has glaciers, etc.
like they do but the weather tends to be better than mountains much further
north or south. (I've climbed other volcanoes there but only made it part way
up Chimborazo.)

ADDED: i.e. so it's not unthinkable for a person in good physical shape who
gets some winter hiking experience, has a fair bit of experience hiking up
mountains overall, gets some glacier skills, and goes on a guided climb. Of
course, people react to altitude a lot differently.

~~~
justinator
Looks like a few hours walk and $250 for a guide:

[https://www.mountainproject.com/route/110735330/standard-
rou...](https://www.mountainproject.com/route/110735330/standard-route)

~~~
saiya-jin
From the description I see on net this is indeed true, with big IF - you
already have prior acclimatization to 5000m+. Without it, its almost
impossible to make it to the top and back at that altitude, unless you have
some super genes. And descriptions mention still 10 hours of hiking and
altitude difference of some 1300m.

Even though the air around equator is thicker, you would most probably already
feel very bad at the carpark at 4800m, if you would come up straight from the
capital. I'd say some 5-7day acclimatization prior to this should be enough
for most fit people.

~~~
ghaff
Right. It's not "hard" in the grand scheme of things of climbing 8000m peaks
in the Himalayas, highly technical climbs, or even a peak like Denali.
However, it's also a far way from pull up to a parking lot and get a little
exercise for the vast majority of people. Altitude makes a big difference for
most. As you say, there's acclimatization. And also there's a world of
difference climbing at 5000m+ relative to climbing relatively near sea level
for almost everyone.

~~~
mkeespiet
I can confirm it is difficult. Not in terms of climbing, but in terms of
breathing. The higher, the smaller your steps. Above 6.000m do you 3 steps and
10 seconds of gasping for air or more. But the view on the summit, that was
the most beautiful one I have every seen. You could see the shadow of the
mountain, see below. In my case there where some clouds, which made it even
more beautiful.
[https://80d2853cc4def76b377d-54344bc01a8b066c84096a8e7a3499a...](https://80d2853cc4def76b377d-54344bc01a8b066c84096a8e7a3499ac.ssl.cf1.rackcdn.com/original/369902.jpg)

~~~
athenot
That is beautiful! And thanks for the feedback.

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saifsadiq1995
Chimborazo in Ecuador has an altitude of 6,310 meters (20,703 feet). Mount
Everest has a higher altitude, and Mauna Kea is "taller." However, Chimborazo
has the distinction of being the "highest mountain above Earth's center."

This is because Earth is not a sphere - it is an oblate spheroid. As an oblate
spheroid, Earth is widest at its equator. Chimborazo is just one degree south
of the equator. At that location, it is 6,384 kilometers (3,967 miles) above
Earth's center, or about 2 kilometers (about 1.2 miles) farther from Earth's
center than Mount Everest.

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blendo
So is the peak of Chimborazo the point on Earth with the lowest delta-v to
orbit?

Compared to a sea level equatorial launch,
[https://space.stackexchange.com/questions/8486/where-is-
the-...](https://space.stackexchange.com/questions/8486/where-is-the-optimal-
location-to-launch-payloads-to-outer-space) claims a 0.2% gravitational
advantage due to height, and a 0.1% advantage due to rotational velociy.

Small, but not nothing.

~~~
alanbernstein
Maybe, but how are you going to carry a rocket up there? Even building a
rocket sled up a mountain seems infeasible.

~~~
informatimago
You don't carry it!

You dig a tunnel (Boring Company), you vacuum it (hyperloop), and you propulse
a rocket (Space X) in it with electromagnets, and lots of batteries (Tesla).

Theorically, you can also come back from space the same way, but 1- you still
need to slow down from orbit, 2- you need to be very precise to enter the
tunnel. This would allow to reload the battery using electromagnetic braking.
Unfortunately, you would need to reverse the orbital speed to come back the
way you came from! This is the costly part. This is why Space X lands on sea
platforms, not where they took off from.

~~~
alanbernstein
I think that's what I meant by "rocket sled", is it really feasible to dig a
tunnel all the way up a mountain?

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gweinberg
If you measure height from the bottom, the tallest building on earth is
probably a shack on top of a mine, and the tallest structure of any sort is an
oil well.

~~~
dmurray
Or maybe a road system.

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stigi
Isn‘t the summit of Chimborazo the farthest point from earths center?

[https://en.wikipedia.org/wiki/Chimborazo](https://en.wikipedia.org/wiki/Chimborazo)

~~~
outside1234
I see you didn't read the article :)

