Just a curious question for those knowledgeable enough to hypothesize back something. Hope I have the right forum, I only took a gamble of where to post.
If a planet, we can say EARTH (if it helps with the answer) had a mountain on it grow so large that it breached the atmosphere.
How would that affect the orbit and rotation (on it’s axis) of that planet? Obviously the amount of mass of the planet would not be proportional at all, that probably would affect the rotation quite a bit.
Is it possible a planet can cease to turn on it’s axis due to poor weight distribution?
I don’t think its possible to distribute a planets weight in a highly asymmetrical fashion out of real materials. There are limits to how high mountains can get and still support their own weight, and those limits are a lot smaller then the 100km that’s the conventional boundary of the atmosphere. In the end, any asymmetry is going to end up getting pulled into a roughly spherical shape by gravity.
Which is why we don’t have any planets whose shape differs from a by more then a small fraction (and most of that fraction is due to the planets rotation, and thus still symmetrical about the Earth’s axis.)
I’m pretty sure the mechanism is the reverse: a planet or moon that becomes tidally locked will start to distort along the axis between it and the object it’s orbiting.
Fictional example: “Fist of God” in the Ringworld series-an asteroid punches a huge hole in the ring (outside to inside), creating a huge mountain which indeed poked above the atmosphere.
The atmosphere that we know of is very thin compared to the planet itself. The atmosphere is only about 11 miles thick compared to a planetary circumference of ~ 25k miles. So even a mountain reaching to the limits of space represents a minor weight imbalance assuming it is composed of typical materials.
The materials the mountain is made of would matter in terms of weight. You could make the mountain out of less dense minerals and whatnot, say a mountain made of talc.
You could put a counterweight on the other side. You could even do something like make the mountain out of mostly lightweight talc and put a small but very dense deposit of gold and lead on the other side of the planet to counteract the weight. You wouldn’t need as much lead and gold because it is much denser and so you wouldn’t have a big mountain on the other side.
Since earth is spinning around in space where there is little drag, I don’t think the volume will matter that much.
One question I have is if the mountain actually breached the atmosphere such that wind cannot go over it but must go around it, how greatly would it affect wind currents and climate? Mountains already affect climate - I imagine that it could cause catastrophic climate change if there were enough of these mountains or if they were wide enough. Imagine a whole mountain range of these and valleys that have little, if any, air circulation with the rest of the ecosystem.
It should also be said that there’s nothing special about breaching the atmosphere. Take away the atmosphere of a planet entirely, and it’ll have negligible effect on the rotation and orbit of the planet.
If it doesn’t have a large moon to stabilize it and the mountain or other mass concentration isn’t on the equator, it can affect the tilt of the planet - it will tend to tip the planet over, moving itself towards the equator. If the planet has a molten interior, the solid crust can slide over the much more massive interior until the mass concentration (an oversized mountain in this case) is nearer the equator; this apparently happened to Mars in its early history I understand. Major volcanic activity built up a mass concentration of dense rock, and the mass dragged the crust across its then-molten mantle until balance was restored.
And Robert Silverberg’s Majipoor has Castle Mount, which technically extends beyond the atmosphere but is kept habitable by ancient machinery that keeps it surrounded by breathable air.
Of interest in this regard is that the five largest volcanoes on Mars (and largest known mountains in the Universe to date) are all located in the plateau region called Tharsis, Olympus being the largest and tallest of a group of gigantic mountains. (They are so large that Mauna Kea or Mauna Loa, Earth’s largest, would almost fit within Olympus’s summit caldera.) A giant ridge trending NE-SW dominates Tharsis, with three of the great volcanoes (Ascraeus Mons, Pavonis Mons, and Arsia Mons in N-S order) sitting atop the ridge. Olympus Mons lies to their northwest just off the Tharsis plateau. To the north of them is the enormously broad-based, relatively low-summit Alba Mons, formerly called Alba Patera. The interesting thing is that Tharsis generally, and Alba Mons in particular, is precisely antipodal to the deep impact feature called Hellas, the lower part of which being the only place off Earth where liquid water open to the atmosphere could exist. There is almost certainly a geotectonic connection here.
Most of the splar system is either too cold or too hot, and/or has inadequate atmosphere. Most of Mars, as well, has too little atmosphere – just as lquid CO[sub]2[/sub] cannot exist on Earth except in hyperbaric chambers, liqwuid H[sub]2[/sub]O requires a minimum pressure. The “bottom” of Hellas achieves that pressure, though most of the time it will be too cold and the humidity ia ao loq it makes Earth’s driest deserts look like a rain forest. But, at least temporarily, standing water can exist in Hellas. (Yes, Europa has water under the ice, and Callisto may as well. But not exposed to what passes for atmosphere on them.)
The asteroid Vesta has an interesting feature related to this question. Note that it has a very large mountain directly on the south pole. That’s not quite an accident, but the asteroid did not shift just to put the moutain there.
That mountain is a central peak of the crater Rheasilvia, one of the largest craters in the Solar System. The impact that created the crater, plus an older one at almost the same place named Veneneia, together removed about 1% of the total mass of Vesta. On a larger planet, this would not influence the planet’s rotation, but Vesta is small enough that it did not recircularize after the impacts. So if the impacts (or at least the first one) did not occur right at the south pole, the asteroid would have been left significantly lopsided. That imbalance would have caused the rotational axis to shift so as to move the crater to one of the poles.
The question is, was the first impact (which was smaller) enough to imbalance the planetoid, or did it require the second, larger impact to do the job?
At any rate, it’s almost certain that the Veneneia was not originally at the south pole.
But Fist-Of-God, like the Eiffel Tower, has negligible mass for its size (a cylinder enclosing the Tower would contain air massing more than the Tower itself). It’s a section of unreasonably thin Ringworld floor (scrith) distorted to breaking point by massive impact and, like the rest of the Ringworld floor, is ridiculously rigid for its size. You couldn’t duplicate that with rock or even with steel.
Of course the Ringworld also has more conventional mountains of similar size - the Spill Mountains, where sea-bottom ooze has been pumped to the Ringworld’s rimwalls to be recirculated over time. But again, the Spill Mountains are supported by the rimwalls, also made of scrith, and they’re gradually sinking (and are meant to ).
I’ve read that the reason the Earth is so much colder now than during the time of the dinosaurs is because the Himalayas force the Jet Stream farther southward. The Jet Stream keeps the air north of it much colder. This creates a general cooling effect in the northern hemisphere, which in turn cools the whole planet.
It’s my understanding that there is a limit to how much weight the Earth’s crust can handle when it comes to very tall mountains. The limit is around 30,000 ft - which, ironically, is the height of the world’s tallest mountains, i.e. the Himalayas. Sorry, no cite.