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  #1  
Old 03-05-2014, 12:02 AM
AaronX AaronX is offline
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Mt. Everest and Earth's tallest mountain

Everest is the tallest mountain on Earth now, but I'm wondering: has it always been the tallest mountain, and will it always be the tallest? (using the same definition. Don't go saying it isn't the tallest once you change the definition.)

I mean, it was made by 2 plates crashing into each other, right? Before it was made, were there other mountains? How were they made, and where did they go? Did they erode down or did Everest overtake them?

Is Everest still growing? Are there other mountains "catching up" to it?
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  #2  
Old 03-05-2014, 12:17 AM
the_diego the_diego is offline
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The Himalayas formed from the crumpling of two continental plates when India slammed into Eurasia. In this kind of collision, the result is upward crumpling. So the Himalayas is still growing while India is shrinking (stop cheering Pakistan!)

I don't know of any similar observed case but a good bet might be the Mediterranean area where plates have been known to slam into each other and then separate. But there are no impressively high peaks there.

Tall mountains that form by the collision of oceanic and continental plates (like Andes) are almost always volcanic. They're not very tall. Mt Aconcagua is an exception. Most volcanic mountains erode very quickly (in geologic terms.) But Aconcagua stopped being a volcano and became the victim of crumpling between the oceanic plate (Nazca) and the south American shield (continent) so it's a hybrid volcanic arc - and result of crumpling (thrust faulting.)

Your other question, ancient tall mountains? The present is the key to the past, so there was likely a mountain similar to Everest (in type of formation if not height) that has either eroded down or was faulted down.

The entire Himalayas is growing as mentioned above but I don't think any other peak is chasing Everest, except maybe K-2.
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Old 03-05-2014, 12:20 AM
buddy431 buddy431 is offline
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Quote:
Originally Posted by AaronX View Post
Everest is the tallest mountain on Earth now, but I'm wondering: has it always been the tallest mountain, and will it always be the tallest? (using the same definition. Don't go saying it isn't the tallest once you change the definition.)

I mean, it was made by 2 plates crashing into each other, right? Before it was made, were there other mountains? How were they made, and where did they go? Did they erode down or did Everest overtake them?

Is Everest still growing? Are there other mountains "catching up" to it?
There were almost certainly mountains taller than Everest in the past, and there certainly will be in the future. Everest is still growing about 4 mm a year, but that won't last forever.

All that being said, it's also true that there were probably never mountains much bigger than Everest. Everest is thought to be about the largest that a mountain can get on Earth before the forces pulling it down necessarily overwhelm the uplifting forces. I think the current consensuses is that erosion due to glaciation is probably the limiting factor for a mountain's height, though there are other factors as well. You might get a 10 km mountain on Earth, but you would never see something like Olympus Mons.
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Old 03-05-2014, 12:36 AM
the_diego the_diego is offline
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^
You mean isostacy and erosion? Those happen to all mountains but the crumpling and thrusting going on in the Himalayas (funny) are outpacing them. Exactly when will India stop pushing northwards into China will be the factor. One thing's sure, it'll be a lame excuse for declaring war on India.
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Old 03-05-2014, 01:05 AM
buddy431 buddy431 is offline
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Originally Posted by the_diego View Post
^
You mean isostacy and erosion? Those happen to all mountains but the crumpling and thrusting going on in the Himalayas (funny) are outpacing them. Exactly when will India stop pushing northwards into China will be the factor. One thing's sure, it'll be a lame excuse for declaring war on India.
Right, isostacy and various forms of erosion; it remains an active field of research what mechanisms are most important in limiting height.

Sure, the Himalaya are still rising, but as they get higher, the forces wearing them down also increase. Mountain ranges often reach a sort of dynamic equilibrium, where they remain at the same height even as the collision that forms them continues to occur. It's not known exactly how much higher Everest will get, but it won't be much higher. A 10 km mountain might be possible, but a 15 km mountain almost certainly isn't.
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  #6  
Old 03-05-2014, 01:38 AM
wedgehed wedgehed is online now
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Well, someone's going to say it eventually...

Everest is the highest mountain on earth. Mauna Kea is twice as tall.
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  #7  
Old 03-05-2014, 01:45 AM
Shakester Shakester is offline
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Mauna Kea is the world's tallest mountain.

Everest is the tallest above sea level.

ETA: Ninjaed :-(

Last edited by Shakester; 03-05-2014 at 01:46 AM..
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  #8  
Old 03-05-2014, 01:49 AM
the_diego the_diego is offline
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It's not like you're comparing a 7-footer standing inside a ditch with a midget standing on a bar stool. One can argue that Everest should also be measured starting from the ocean floor. After all, what's a little water? Why not measure everything relative to the point at the center of the Earth? Ultimately, you will still be asking "what's the highest point on Earth" and that will be Everest.
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  #9  
Old 03-05-2014, 01:57 AM
Enilno Enilno is offline
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Originally Posted by the_diego View Post
Why not measure everything relative to the point at the center of the Earth? Ultimately, you will still be asking "what's the highest point on Earth" and that will be Everest.
But by that measurement, the mountain with the highest elevation is actually Mount Chimborazo, since it is so close to the equator.
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  #10  
Old 03-05-2014, 02:08 AM
the_diego the_diego is offline
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That one slipped past me, thanks.
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  #11  
Old 03-05-2014, 02:46 AM
Alessan Alessan is offline
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Measured from the ocean floor, Everest is still the tallest peak in the world.

Anyway, back to the OP: I'm pretty sure that at certain points in prehistory, both the Alps and the Appalachians were taller than the Himalayas.
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  #12  
Old 03-05-2014, 02:52 AM
the_diego the_diego is offline
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My guess is the highest mountains were formed when all the ancient continents slammed together to form the pangea mega-continent.
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  #13  
Old 03-05-2014, 02:58 AM
the_diego the_diego is offline
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But a better contender is when the Earth's surface was just cooling, no ocean and atmosphere yet, steady bombardment by meteors. You must have had surface features tens to hundresd of miles relative to their highs and lows. But an atmosphere makes for a very smooth surface.
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  #14  
Old 03-05-2014, 03:11 AM
Alessan Alessan is offline
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Originally Posted by the_diego View Post
My guess is the highest mountains were formed when all the ancient continents slammed together to form the pangea mega-continent.
That would be the Appalachians - they were created when North America slammed into Africa.
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  #15  
Old 03-05-2014, 05:43 AM
AaronX AaronX is offline
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So Everest has been and probably will be the tallest throughout human history?
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Old 03-05-2014, 07:02 AM
Chief Pedant Chief Pedant is offline
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Originally Posted by Enilno View Post
But by that measurement, the mountain with the highest elevation is actually Mount Chimborazo, since it is so close to the equator.
The only kind of tallest anyone (except locals) cares about is elevation above the geoid estimation.

The thing that makes tallness "cool" is how far above the leveling force of gravity a land mass has been able to get.

Any other definition of tallness is simply the local tourist industry trying to find significance where none otherwise exists.

Last edited by Chief Pedant; 03-05-2014 at 07:03 AM..
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  #17  
Old 03-05-2014, 07:05 AM
Chief Pedant Chief Pedant is offline
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Originally Posted by AaronX View Post
So Everest has been and probably will be the tallest throughout human history?
Assuming we take our starting point as 200kya and get bumped off in a similar future timeframe, sure.
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  #18  
Old 03-05-2014, 08:41 AM
Smeghead Smeghead is offline
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I'm sure that in various programs or articles I've watched or read about the history of Earth's geology, they've casually mentioned mountains or mountain ranges that would have been taller than the Himalayas - we're talking about Pangaea or the stages of its breakup - but I couldn't dig up a cite if my life depended on it. I think we need a paleogeologist.
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  #19  
Old 03-05-2014, 08:56 AM
Jonathan Chance Jonathan Chance is offline
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Quote:
Originally Posted by AaronX View Post
So Everest has been and probably will be the tallest throughout human history?
We should sure hope so.
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  #20  
Old 03-05-2014, 11:11 AM
jtur88 jtur88 is online now
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The stated elevation of Mt. Everest has changed considerably, just during my lifetime. Not because it is changing, but because the accuracy of means of measurement did not reach one-meter accuracy until just a few decades ago. In such a short period of time, there can be very little certainty about whether the peak (or any other competitors) is actually changing elevation. The current elevation (29,029 feet) was stated in 1955, independently confirmed in 1975, and has apparently remained the same for at least 60 years. The highest number I can get on Google Earth is 29,001.

Last edited by jtur88; 03-05-2014 at 11:16 AM..
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  #21  
Old 03-05-2014, 12:49 PM
Chronos Chronos is offline
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You don't necessarily need to be able to measure the height precisely to be able to measure the change in height precisely. If the error in your measurement technique is dominated by systematic but unknown errors, then subtracting two measurements will cancel out the error.
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  #22  
Old 03-05-2014, 01:08 PM
bob++ bob++ is offline
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When Radhanath Sikdar, a mathematician and surveyor from Bengal, first identified Everest as the world's highest peak in 1852, he measured it to be exactly 29,000ft (8,839m) high, but it was [eventually] publicly declared to be 29,002ft. The arbitrary addition of 2ft was to avoid the impression that an exact height of 29,000ft was nothing more than a rounded estimate.

http://qi.com/infocloud/mount-everest
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  #23  
Old 03-05-2014, 05:05 PM
hibernicus hibernicus is offline
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Quote:
Originally Posted by buddy431 View Post
There were almost certainly mountains taller than Everest in the past, and there certainly will be in the future.
Since the convention is to measure height above sea level, Everest was taller during the last ice age than it is now (even accounting for the fact that it has continued to rise since then.)
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  #24  
Old 03-05-2014, 06:20 PM
kanicbird kanicbird is offline
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I believe K2 was the tallest mountain for a short time as little as 10 years ago. (due to human measurements).
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  #25  
Old 03-05-2014, 06:31 PM
jtur88 jtur88 is online now
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Defining the "tallest mountain" is itself problematic, as at least four realistic definitions could be employed, with different results.

1. The point on the surface furthest from the center of the earth. Because the earth is ellipsoid, a mountain 20 miles high in central Antarctica would be closer to the center of the earth than a beach in Singapore, on the equator. Sitting here on the Texas gulf coast, I am further from the center of the earth than the highest Antarctic mountain peak.

2. The highest point above sea level. But because Mount Everest is not visible from the sea, that has no relevance. It's like saying the tallest basketball player plays for the Denver Nuggets, where he is the highest above sea level.

3. The point highest above surrounding terrain (the basketball court above), where the peak is the furthest above any relevant observers interested in how high it is.

4. As in 3, but the case of a mountain on an island could be argued to have a given height above the floor of the ocean, irrespective of the historically variable level of the water that covers the lower parts of the mountain. It's all still mountain, all the way down past the beach.

Which of the above do you wish to use as a definition of "tallest mountain"?

Last edited by jtur88; 03-05-2014 at 06:36 PM..
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  #26  
Old 03-05-2014, 06:51 PM
Mangosteen Mangosteen is offline
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Another thing is that when one sees Everest in person, it doesn't really look that tall because there are several mountains in the immediate area that are almost as tall. It definitely has to be pointed out to you. Also one of the best viewing places is a "hill" named Kala Pattar. Its height is about 18,000 feet so Everest is "only" 11,000 feet taller.
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  #27  
Old 03-06-2014, 02:34 AM
dtilque dtilque is offline
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The Urals are another mountain range that were among the tallest in the world when they were young. And like other such ranges, they formed from a tectonic collision.
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  #28  
Old 03-06-2014, 09:55 AM
GreasyJack GreasyJack is offline
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One of the problems with talking about old mountain ranges is that even though it's fairly straightforward for structural geologists to determine roughly how much crustal thickening occurred, it's much harder to determine how directly that would have been reflected in elevation. For example, the Rockies were thought to be a not-especially-tall broad highland during the subduction event that formed them, but the high topography today owes its existence to the interaction between the earlier thickened crust and more recent extension and uplift in western North America. If geologists were looking at the Rockies a billion years from now, the crustal thickening when they were formed would be obvious, but there might not be a lot of evidence to suggest what the current mountain range was like.

What further complicates things is that the mechanisms for continental-continental plate collisions aren't particularly well understood. During the early days of plate tectonic theory, the Himalayas were a little baffling. The main driver of plate movement is the force of subducting plates "sinking" in the mantle (slab pull) but continental crust doesn't subduct. That makes a plate boundary like the Himalayas, where you've got two relatively large pieces of continental crust that appear to have been pushing together for a very long time, very hard to explain. It seems that the Indian Plate must still be attached to the sinking ancient oceanic crust, but the exact mechanism for that, and what happened to a large portion of "missing" continental crust on the Indian Plate, is still not fully understood.

So, with that in mind, it's not entirely clear how common Himalayan-style plate collisions have been throughout Earth history or if them being manifested by extremely tall mountain ranges is the usual situation. It could be that the situation in the Himalayas today is rare and that Mt. Everest really is one of the tallest mountains ever.
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