Pretty simple question I guess. In the history of the earth, have there ever been mountains higher than Everest’s current elevation that have since eroded or otherwise become lower?
(I do mean “higher” in the sense of greater elevation above sea level, as opposed to a “taller” mountain like Mauna Kea.)
How could we know? There are plenty of mountain ranges that have eroded - the Grampians for one.
I don’t know if any were actually taller than Mt. Everest, but the White Mountains in New England were supposedly as tall as much of the Himalayas at one time.
http://seacoastnh.com/The_Arts/Book_of_the_Week/A_Time_Before_New_Hampshire/
Probably, and possibly even Mt. Everest. Mountains form from upthrusting when tectonic plates meet. Their height will depend on the underlying power of the collision. To assert that Mt. Everest is the tallest ever you have to assume that India hitting the Asia mainland was the most powerful upthrusting in the history of the movement of contintental plates and that Everest hasn’t eroded at all since it was formed. Both are unlikely.
There’s a book about exploring the Solar System entitled Higher than Everest, the reference apparently being to the Martian shield volcanoes (Olympus Mons, the Tharsis Ridge trio, etc.) which are factually significantly higher than Everest, though like Mauna Kea and Mauna Loa their slopes are so gentle that it would simply seem an enormous uphill stroll. Mount Maxwell on Venus also appears to be higher than Everest.
Canada’s Lithoprobe research program(me) has a website which includes this:
From a site for investors in Canadian mineral-exploration companies:
“studbury”? I think he meant sudbury.
Naah – Sudbury is where you find the mines; Studbury is where you find the miners! 
(It probably actually was a typo; it’s another message board.)
There’s this thing called “isostacy” that determines how much weight the crust of the earth can support before sinking under that weight. I can’t describe it all accurately because my pea brain just won’t wrap around many of the concepts, but it involves gravity and atmosphere and bouyancy, etc. If you have a scientific mind, look here: http://scienceworld.wolfram.com/physics/Isostacy.html
Although the Indian plate is still moving northward, uplifting the Himalayas, Everest is about as high as a mountain can get on the Earth’s surface considering the size of its base. The weight of the mountain depresses the crust it rests on. For Everest to get higher, its base would have to be wider, spreading across a wider stretch of land and redistributing its weight.
In general, 30,000 feet is about as high as anything can get on Earth. The same equations prove that things can get much higher on other planets, like Mars.
However, mountains are constantly eroding at the same time they are being formed - they don’t form and then begin eroding. While Everest may have been taller in the past than it is now, this is not necessarily so - it could be about as tall as it’s ever been, if erosion has kept pace with its uplift. And the faster a mountain rises, the faster it erodes (because the slopes will be steeper), so this kind of correlation might well keep the height below a certain limit.
Oddly enough, it’s also possible that erosion in the Himalayan region has helped make Everest taller than it would be otherwise.
From this page
Yes, and that is also the answer to the question. There is a mountain taller than Mt Everest and it’s Mt. Everest. It rises a couple of milimeters each year because of tectonic shift so it is now taller than when the question was asked.
The Mauna Loa rises almost 13 kilometers from the sea bed.
I read an article a few years ago (OK, probably 30 years ago) by the late, great Isaac Asimov where he handled questions like this one. He pointed out Mauna Loa as being one of the contenders for the Highest Mountain category, along with some undersea mounts in the deep-sea trenches. The point was “how do you define highest?”
We had that discussion over in this thread.
But this doesn’t answer my question, which is what the rate of erosion of Mt. Everest is. If it is more than a couple of millimeters a year, then the mountain is not taller now than in the past. We need to know both halves of the processes at work for a proper answer.
And Ale, please notice that the OP specifically ruled out underwater mountains like Mauna Loa.
That’s going to be a tricky one, I think. You’re talking about erosion off the top of the mountain itself, right? Without regard to the amount of snow cover?
I did find this page where it says
It’s not at all clear to me whether that 2.4 inch per year figure is net growth measured at the tops of the mountains (i.e., including the effects of erosion) or just the amount of upthrust. Still, I’d be surprised if more than 2.4 inches of rock were being scoured off the top of Everest each year underneath all that snow, so I’m guessing that the top of Everest is still going up.
It is not a case of 2.4 inches being scoured off each year. The process is a bit more cataclysmic than that.
Mt Cook/Aoraki, which is New Zealand’s highest point recently had 10 metres slide off the top in a rockfall. THe same could easily happen to Everest and has undoubtedly happened in the past. (Although not in the recorded past.)
Just for the record, let’s deal with a couple of red herrings that could show up here:
“Highest” in the context of the question means “greatest altitude above sea level” as opposed to the two alternative meanings of “greatest altitude change from base to summit” (Mauna Kea) and “farthest from the center of the Earth” (Chimborazo, IIRC).
There are unsubstantiated claims that K-2 (which is concededly nearly as tall as Everest) or other Himalayan peaks are actually higher than Everest. If and when one of these stands up to peer review and is accepted by the oreographic community, that will be fine; until then, Everest is the present record holder.
I note very little evidence on the Net for estimated height of past mountain ranges. Certainly the collisions that gave rise to Rodinia and Pangaea must have pushed up some monsters. But there seems to be little discussion of what reasonable guesses of altitude for them may have been. Any professional geologists with a knowledge of the physics underlying colliding-plate upthrusts that could deal with this?
That will teach me not to post past 1 AM… :smack:
But it seems reasonable to conclude that Everest is taller now than it was one year ago (even if we can’t definitely say that it’s taller now than it was 200 years ago or that Everest is getting taller in the long run).