
Why Are Mountains So High? Mysterious Anomaly Exposes Limits of Theory - hhs
https://scitechdaily.com/why-are-mountains-so-high-mysterious-anomaly-exposes-limits-of-conventional-theory/
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atlantictopacif
It seems like the headline should be "Why Aren't Mountains Higher?" If I'm
reading it right, once mountains hit an certain height, the erosion increases
unpredictably, meaning height is reduced beyond what is expected.

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_nalply
I theorize that there are two factors: First glaciers are efficient at gnawing
at mountains, and second rock is brittle therefore mountains tend to set in
the timespans of millenia even if there are no landslides. The second one
might be the one that is unpredictable.

In Switzerland there's a tiny town, Brinzauls, which is setting as a whole
together with the slope it sits on about three or six feet a year, because in
the depth of a few hundred feet there's water flowing through the cracks of
the bedrock. There are plans to bore a tunnel along the water-carrying stratum
to drain it to stop the movement downwards.

This is just an example of one of the many things that might happen to crop
down mountains.

The setting movement is unpredictable because it also depends on the climate.
In oceanic climates water could quite literally be dissolving mountains from
below.

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yxhuvud
Freezing temperatures and wetness during winters are also important as the
power of freezing water in cracks are so great.

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_nalply
Yes, generally this is true, but for the special case in Switzerland is it
not, because the cracks are so deep underground (several hundred feets).

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mcguire
" _The researchers analyzed samples from a broad range of mountain landscapes
across the tropics, including Venezuela, Brazil, Guatemala, Costa Rica and
Taiwan, controlling for rock type and climate conditions to assess parallel
comparisons. They found that after mountains reach a certain elevation,
channels between mountains suddenly become extremely sensitive to subtle
changes in their inclines, thereby limiting the height of the mountains above.
They added data from hundreds of mountain ranges worldwide and found they
followed a similar pattern: the height, or relief, of the landscape is capped
after crossing a threshold driven by channel steepness._ "

Could someone walk through this pattern in simplified English? I'm not making
heads nor tails of the article.

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klingonopera
" _The researchers looked at samples from a big number of mountain landscapes
[...], comparing their rock types and climate conditions. They found that once
mountains pass a specific height, the channels_ [they mean the area between
mountain peaks/ridgelines, basically the path e.g. a glacier "rides" on]
_become very sensitive to even the smallest changes in their steepness, and
that limits the heights of the mountains around them. After adding more data
from hundreds of mountain ranges, they could confirm this pattern, that
mountain height is limited once its channel 's steepness crosses a certain
value._"

Not sure if I understood "mountain channel" correctly, I don't know much about
geology, please correct me if I'm wrong.

EDIT: Think I got "channel" correct though, there's e.g. the English Channel,
if you imagine it without water, England and France could be seen like
mountains.

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skrebbel
Uh, the English Channel is only 174m deep.

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bartread
I seem to remember reading somewhere recently - and, annoyingly, I can't find
it so have no idea whether it was a "reputable" source - that gravity itself
imposes a hard limit on the maximum height of mountains. I guess it makes
sense given that the larger a mass in space is, the more gravity forces it
into a spherical configuration. Still, happy to be told I'm wrong.

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OnlineCourage
Probably not correct since the earth is pear shaped not spherical, and the
size of mountains are quite small relative to the earth's curvature. However
from the article erosion of mountains seems to be impacted by water, limiting
height, so on a smaller similar planet by material and water composition it
would stand to reason that force of water given the same mass would be less so
perhaps mountains would erode more slowly relative to continental drift and
therefore be higher.

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perl4ever
I was reading about extraterrestrial mountains once, and what I retained was
that there aren't any mountains on other planets/moons that are really
amazingly higher than earth. By which I would infer that water erosion
probably isn't the overwhelming limiting factor.

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webnrrd2k
Umm... not true.

"The highest mountain on Mars is also the highest mountain and volcano in the
entire solar system. It is called Olympus Mons and is 16 miles (24 kilometers)
high which makes it about three times higher than Mt. Everest"

My knowlege is old, but iirc I think the reason for Martian mountains being
(potentially) higher than earth is the the rock is physically stronger due to
lower water content. On earth, the water that eventually makes its way into
rocks reduces it's strength, but, on Mars, the relative lack of water makes
the rocks physically stronger.

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perl4ever
1\. You're telling me what _I_ mean by "really amazingly higher"? Well, you
don't get to do that. In my opinion, the scarp/cliff around Olympus Mons
doesn't count, and disregarding that, it's less than 40% higher than from
Mauna Kea/Loa to the seafloor. Frankly, a mountain would have to be well over
double earth's highest base-to-peak to be "really amazing" to me. Ten times
would really be "really amazing".

2\. There's a Wikipedia page on the subject of tallest mountains in the solar
system and it says the current leader is (probably) Rheasilvia on Vesta.

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Razengan
Layman curiosity about mountains (for fictional worldbuilding):

Are they completely solid inside?

Or can they be "porous" with natural caves or holes internally?

How/why?

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ip26
They can have caves and such. Granite and I believe also sandstone tends to be
totally solid, but limestone tends to form extensive cave networks from water
seeping through the rock. Basalt can also have caves from anciet magma
chambers but I don't think those usually lend themselves to human exploration.

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hyperpallium
Surely covered in the article (paywalled) or literature, but sounds similar to
a _critical angle of repose_
[https://wikipedia.org/wiki/Angle_of_repose](https://wikipedia.org/wiki/Angle_of_repose)
where a pile of sand subsides if too steep.

Not applicable to hard rock (non-granular), but a river bank profile with
erosion due to flow granular particles, may behave as if granular.

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drojas
The question is why are they so high if there are limiting factors previously
not fully accounted for within the current models. The folks from the Electric
Universe paradigm have an alternative model that can explain some of the
features "standard" geology may struggle with. I think this might be a good
example of one of those.

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tempguy9999
> folks from the Electric Universe paradigm have an alternative model

Sigh. Go on then. Don't tell us it exists, provide a link.

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drojas
I apologize. Here [http://www.eu-geology.com/?page_id=192](http://www.eu-
geology.com/?page_id=192) and
[https://www.google.com/search?q=electric%20universe%20mounta...](https://www.google.com/search?q=electric%20universe%20mountains)

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mcguire
" _How could the process of fossilization [of sand dunes into mountains] be
imagined? A dune of loose conglomerate can not simply sink into the earth, be
transformed by penetrating liquid magma, and come back to the surface as rock,
while the typical dune structure and shape is maintained. The process of
fossilization must therefore take place at the surface and it must happen
quickly. This is where electricity comes into play. On one hand there is the
possibility of melting and solidification, when electricity is introduced
through the top of the mountain. On the other hand, it may be a direct
electrical conversion. Experiments [Steinbacher 2011, 586] have shown that it
is entirely possible to transform dust and soil electrically into different
types of rocks. The process first melts the material mixture. Then crystals of
different size and composition form. Upon further exposure to electricity,
they begin to melt itself. Essential parameters are the composition of the
material, current and voltage, and the exposure time._ "

That's terrifying.

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Balgair
> The process of fossilization must therefore take place at the surface and it
> must happen quickly.

> Essential parameters are the composition of the material, current and
> voltage, and the exposure time.

Is this all trying to say that mountains are just fossilized sand? That is
certainly a .. novel... theory of geology.

Fossilization of organic matter generally takes about 10k years, give or take.
Fossil is a word that tends to encompass a lot of things though, so it
depends.

Still, the amps that you'd have to pump through a dune to get it all to
melt/solidify would be astonishing. Think a constant lightening bolt for years
on end. Most sands are insulators afterall.

