Also Greenland and Antartica have so much ice it produces a gravitational pull on the surrounding water. Its one of the reasons sea levels rise in most of the world when that gravity weakens and water is redistributed.
This effect only has an impact on the surrounding sea level, it somewhat counterbalances the local sea level rise from the melting ice sheet. It has no impact ( likes tides) on global sea levels.
Compared to the usual acceleration of gravity that is almost 9.8m/s^2, it's only a 0.0048 = 0.48%. That is the slope of the real see compared to an ideal sea where there is no gravity from the ice. I'm using a spherical ice instead of a sheet of ice. With a sheet of ice the effect would be much smaller, but I'm too lazy to look up.
The gravity from the ice decrease as 1/r^2 when you go farther. We must integrate the slope to get the volume. I'm going to use a flat Earth, to simplify the calculation, but as the 1/r^2 reductions is quite fast, it's not a problem. With a curved Earth it will be more, but not too much.
Also, we must multiply by 2*pi*r to get the volume in the flat surface all around the sphere instead of the surface of a vertical cut of the sea.
The radios of the Earth is 6371km, so the "distance" to the north pole is 6371kmpi=20000km and we can cut the integral there https://www.wolframalpha.com/input?i=Integral+from+185+to+20... The result is 48,000 km^3 of water. But melting the Antarctic Ice sheet will release 24,300,000 km^3 So it's only a .2% more.
In other units, melting all the Antarctic Ice would increase the sea level like 58m (190ft). The additional effect of the gravity is less than .3m (1ft) And I expect that a calculation if a sheet shaped ice will give a much smaller result.
First, let's calculate the additional high. It's better to imagine the 0 is in the oposite pole, and the additional height is very similar to the old integral without the 2*pi*r https://www.wolframalpha.com/input?i=Integral+from+x+to+2000... i.e.
0.0048 * 185^2 * (1/r - 1/20000)
Now we must integrate it again, with the 2*pi*r Integral from 185 to 20000 of (0.0048 * 185^2 * (1/r-1/20000)), that is only 606km^3, so 1/80 of my previous calculation. So, fixing the last part of my comment with the new numbers:
But melting the Antarctic Ice sheet will release 24,300,000 km^3 So it's only a .0025% more. In other units, melting all the Antarctic Ice would increase the sea level like 58m (190ft). The additional effect of the gravity is less than .0004m (4mm, 1/8 inch)
Thank you! I was wondering why it looked so different from any other landmass, with the land being so much "sparser".
The end of the 7-second animated video on your link shows a landmass that looks much more like the rest of the Earth.
Utterly fascinating to see a "hidden continent" like this -- I'm so used to unfamiliar maps being fantasy (like Westeros from Game of Thrones), so it's quite remarkable to see an unfamiliar map that is on our very planet.
if all the ice in antarctic melted (and nothing else happened), it would cause sea levels in antarctic to fall. That's because all the ice currently there exerts enough of a gravitation pull to increase sea levels there now. That being said there would be other things like the melting of the Greenland ice sheet and thermal expansion of the oceans that would be acting to increase the sea level.
I think the old article (and thus the picture) is from the version 2 dataset, and now they have realeased version 3. I went ahead and rendered the version 3 dataset with QGIS: https://i.imgur.com/jj8B4D8.jpg
Well, land is heavier than water so it drops to the bottom of the earth (South Pole) whereas there is nothing at the top of the earth (North Pole), just water and ice. (Joking obviously, I’m not a flat/hollow-earther or anything similar)
One pattern that is curiously consistent is that broadly land tends to be antipodal to ocean (and not just because there’s more ocean in general - there’s a genuine statistical skew) - so having land at one pole and none at the other matches that overall pattern. (https://www.geodatos.net/en/antipodes)
Basically a surprisingly large proportion of antipodal pairs have land at one end and water at the other (although water-water is also common).
In other words it would certainly be more surprising to have land at both poles; and we should be unsurprised if we find land at neither or land at one and not the other.
So by that measure the poles are fairly typical of other antipodes.
To me that really looks like pattern matching where there isn't actually any (though I'd like to know more details around the "statistical skew")- saying that there's a lot of antipodal land-water or water-water pairs only makes sense considering the vast majority of the planet is water.
Regardless, it's just an interesting snapshot in time considering continental drift.
30% of the surface is land. But only 15% of land has land antipodal to it, which certainly initially feels like less than you would expect by random chance.
It’s easy to fall into some counterintuitive fallacies reasoning about this though because we’re considering a spherical surface pairwise and you might be tempted to say ‘ah, but we’re counting the antipodal land twice so that probably accounts for the 15%/30% thing’ - but I don’t think that follows; that 15% with land antipodal to it can be thought of as two sets of 7.5% of the land, which are antipodal to one another - the ‘double counting’ doesn’t work that way to eliminate the anomaly.
If you look at the Pacific Ocean from "top" (i.e. get a globe and rotate it), you'll see that it effectively covers almost entire hemisphere. So there is no surprise that most of the land has no antipodal land. The more interesting question is why initial continent, Pangea existed as such instead of the bunch of the smaller continents, which would seem more logical and likely.
EDIT: also, do we know if there were no other continents that submerged?
Just for curiosities sake I fell down the rabbit hole and ran the numbers (please someone correct me if I'm wrong on this - it's been a loooooong time since I did statistics). This is all assuming some sort of even distribution of land/water, so the numbers don't reflect real world continental distribution, but I don't know how to account for that.
We have a 30% chance of picking a random point on Earth and getting land. Because earth is so big and these theoretical points are so small I'm going to assume that one point of land existing doesn't effect the odds of another piece of land existing. So that's two antipodal points, each with a 30% chance of being land.
Putting that into a probability calculator (again, long time since statistics) that gives us odds of both point A & B being land as 9%. If we flip that around and go with the 30% land and 70% water odds we end up with a chance of 21%. It seems like there's actually MORE land that's antipodal to other land than we'd expect statistically? I must have some bad math here.
> We have a 30% chance of picking a random point on Earth and getting land. Because earth is so big and these theoretical points are so small I'm going to assume that one point of land existing doesn't effect the odds of another piece of land existing.
This is the issue.
A large contributor of the "point antipodal to land is water" anomaly is the typical size of land masses. If, for example, the average size of land masses was 30% of earth's area, then we'd have a single large land mass (Pangaea style), and all antipodal points would be water.
The approximation of independence here doesn't reflect reality. Eurasia alone is more than 10% of the land area of Earth.
Not sure where 21% comes from - if 3/10 of points are on land, 9/100 antipode-pairs should be land-land, and that means 9/100 / 30/100 = 9/30 = 30% of land should have land opposite it, and conversely 70% should have water?
But the true numbers are 15%/85% - on the actual earth, land is more likely to have ocean opposite it than random chance would suggest.
Analyzing whether items sufficiently far from the ‘expected’ random distribution as to be statistically significant is a rather different exercise though.
Is antipodal land a physical property of Earth's continents, or is it mathematical fact of distribution on spheres?
If we distribute chunks of land randomly on a sphere we would expect roughly the same amount of land on any randomly-chosen hemisphere. But what can we say about the average amount of land in the hemisphere with the most land?
My intuition says that in an Earth-like sphere, with 29% land and 71% water, there's a high chance of there existing a hemisphere with almost all of the land.
I have no idea how to prove this empirically, but it seems like a really nice maths problem.
My understanding is that it is a physical property, arising from the fact that crustal basically all crustal growth occurs in ocean floors .
The locations of the continents spend the vast majority of the time either approaching a clustered state, or leaving it.
Because the thick continents with land are a minority of the surface [2], They only briefly pass through a period of even dispersal when passing from one clustered state to another.
>My intuition says that in an Earth-like sphere, with 29% land and 71% water, there's a high chance of there existing a hemisphere with almost all of the land
Can you explain more? If you have 7 or so plates with land, why would you expect them to have a high chance of being in the same hemisphere? The math is the same as flipping a coin 7 times. Flip the first and see which side it lands on, then flip the remaining 6 and see how many match the same hemisphere. What am I missing?
> The math is the same as flipping a coin 7 times [...]
I'm not saying that a particular hemisphere has a high change of having most of the land; I'm saying that there will be a hemisphere that has this chance.
29% of Earth is land and 80% of this land is in the land hemisphere, so this problem would be the equivalent of rolling a D48 14 times and placing the dice on a table so that any 11 of the rolled numbers are visible if I look at it from the top.
I see, so if you have the freedom to define hemispheres however you want, what are the chances you can fit a definition that captures the majority.
I think that is also fairly solvable. let me think on it. I cant understand your example, but is this the same?:
Roll a d100 once per continent (e.g. 7 times) and write the numbers down.
What percent of the time can you pick a range 50 numbers that captures all 7 results. the range can wrap around from 100 to 0.
The problem would be easy to monte carlo, but I would have to think about how to solve it in closed form.
Your example is not the same for two reasons:
1. You are assuming there always are 7 continents and each of them contains 1% of all space on the Earth's surface. I assume there are 14 continents with 2% of the Earth's surface each, which is still incorrect but it's closer to reality.
2. I'm not defining hemisphere however I want: I'm using the canonical definition of hemisphere, but choosing any hemisphere for me dice. For example, two continents that appear on numbers 1 and 48 can never be in the same hemisphere.
My question is the probability of being able to choose 11 of the 14 continents so that there exists a hemisphere that contains all of them, like the land hemisphere contains 80% of the Earth's land.
1)When you say you are using the canonical definition of hemisphere, do you mean North and South? Or are you talking about East and West as well?
2) Out of curiosity, why 14 continents?
If you are using North and South as pre-defined hemispheres, ignoring East and West, I do think it can be reduced down to a coin flip if you want to prove that plates are unlikely to almost all be in the same hemisphere. This is because allowing them to overlap allows more clustering, not less.
12/14 continents is >80% and 11/14 is <80%.
If you drop a continent randomly, it has a 50/50 chance of being in the north or south.
The probability of 12 or more being in the northern hemisphere is 0.647%.
The probability of 12 or more being in the southern hemisphere is 0.647%.
Together, the probability of 12 or more being in the same N/S hemisphere is 1.294%
You can do the same for E and W, getting another 1.294%, for a total of 2.588% chance.
This is allowing the continents to overlap, so the real chance would be lower.
The Northern, Southern, Eastern, and Western Hemispheres are just four of the infinite hemispheres of a sphere.
By "canonical definition of hemisphere" I'm talking about the surface of any half-sphere that covers half of the Earth; the "joke" in my proof is that you can choose any one.
For any two continents there's always a hemisphere that contains both of them (assuming you don't worry about the semicircle in the border of the hemisphere). If you put three equidistant continents with the maximum possible distance between them (so that they form an equilateral triangle whose centre is the centre of the sphere) then you can't do anything about it.
Think it like shining a light from some point in space that lights 80% of the land in Earth.
It also depends on how strongly clustered the land tends to be - if the land is all going to be continuous then presumably there are more distributions of that land that are weighted towards a single hemisphere.
Suspect there’s something to do with the fractal dimension of the coastlines as well. Agreed - sounds like a rich vein of math.
Are there any interesting sci-fi novels or games that take place in the (far) future in Antarctica with humanity being forced away from the equator by the increasing temperatures?
Midwinter and Flames of Freedom were so far ahead of their time. It’s like Mike Singleton had a vision from the future of Just Cause or Far Cry or something and tried to build it using 90s technology.
"Almost all remaining life on Earth has adapted to live in Antarctica. Elsewhere life is extinct except for some evidence of biological activity in the Himalayan mountains."
It doesn't take place in Antarctica, but The Drowned World by J.G. Ballard describes such a future - the last remnants of civilization have retreated to Greenland, and London is a flooded tropical lagoon.
Antarctica looks like a very interesting land, perhaps because it is forbidden to us. Still, with that geography alone I wish we could swap its place with something like Australia. Perhaps with advanced geo-engineering it would be possible to someday rotate the earth in such a way that Australia ends up at the South Pole and Antarctica is uplifted to a warmer climate.
I think the Australians might have a few objections to that proposal... As one of them, I know I do at least!
It is interesting how much more archipelago-like Antarctica is. I wonder if that would mean fewer interior deserts than a large continent like Australia has
> I think the Australians might have a few objections to that proposal... As one of them, I know I do at least!
Well, Australia claims about half of Antarctica so as long as we can enforce that claim maybe it's not the end of the country. Just have to declare part of it "New Southern New South Wales" and take it from there.
> I wonder if that would mean fewer interior deserts than a large continent like Australia has.
There Arabian pensinsula are the Sahara are surrounded on three sides by sea, but they're still very dry. The Sahara and Arabian deserts go right up to the coast. As mentioned in my reply to your other reply, as far as I know it's not a lack of water but what happens to the water once it's evaporated that causes the dryness in those areas - it goes up into the high atmosphere and comes down in rain over the tropics. Wish I remembered the name though.
> as far as I know it's not a lack of water but what happens to the water once it's evaporated that causes the dryness in those areas - it goes up into the high atmosphere and comes down in rain over the tropics. Wish I remembered the name though.
It's the other way around - the subtropical ridges are high pressure high altitude masses of dry air that fall to the surface around 30 N & S. This dry air is then sucked back to the equator as the Trade Winds, which further dry out the sub tropics.
> Well, Australia claims about half of Antarctica so as long as we can enforce that claim maybe it's not the end of the country.
I have always wondered how this would turn out. Currently not many other countries recognise our claims, but so far there's been no reason to enforce them. Given out proximity we are in a good position to enforce them, and the likes of BHP and Rio Tinto would love access to all the possible resources.
Only because it's at the south pole. If we tilted the earth a bit, it would warm up and start raining. But if we tilted the earth a bit, Australia could probably also get wetter. As far as I understand it, the dryness of Australia, the Sahara etc are caused by the particular location from the equator, where moist air is lifted and brought to the equator and dumped there as rain. So if we pushed Australia further from the equator it would get a bit damper and maybe Indonesia would dry out.
I recommend we don't adopt this program of rotating the earth. It's almost certainly worse than just inventing fission power and pumping desalinated sea water to wherever we want to de-desertify. We'd probably also be better off if we wasted quintillions of dollaeuroyuans on a program to terraform Mars that ends in complete failure and the deaths of millions of workers over a century, but that's also an outcome I recommend we avoid.
There are lots of countries closer to the equator - they are wetter.. large body masses have continental clima, which enocourages the growth of dessert, but they usually do so only when the war of forrest vs savannah is lost by the forrest. Which can cling to areas quiet defiantly, for example the last big forrests in syria, that once covered the middle east
The dryness of Australia comes from the fact that current bring cold Antarctic water up to its west coast which leads to dry winds that blow eastward, which compounds with the complete lack of any mountain ranges to serve as rain shields to leave most of the continent dry. Even the mountains in the east of the continent are barely high enough to form a rain shield, if they were even a bit smaller then the east coast would be as dry as the rest of the continent.
Moist tropical air barely reaches the very top of Australia - instead it hits places like Java, where the abundant rainfall and numerous active volcanoes provide ridiculously fertile land that currently supports 150 million people - 5x that of Australia - despite being 50 times smaller.
I believe that the term you were looking for was toponymy, avoids the awkwardness of "geography, but off-earth": and join Pluto on the toponymic B-team.
I wonder if the locations researchers are staying at are located on top of the land or if it's just randomly located and could be either. Like if all (or a majority of) the ice melted how big of an impact would it have on the locations?
McMurdo station (the biggest one) is standing on land and does thaw in summer [1]. That's on an island at the outskirts of Antarctica though, so I don't imagine it's representative of stations elsewhere on the continent.
Scientific implications would be IceCube would no longer work, because the premise is based on the detector(s) being drilled 2 km into the glacier. You can't just bury it in rock, it specifically needs a transparent medium and ice is surprisingly good for neutrino propagation. The other telescopes would probably be fine, provided it was still sufficiently dry. SPT and BICEP are mostly taking advantage of the location - e.g. high altitude, extremely low humidity and extremely radio quiet, to a lesser extent the ability to stare at the same patch of sky all year. I guess you'd lose a lot of the environmental advantages, but maybe it would still be a desert.
There isn't a particularly good reason why everything is sited there beyond geopolitics. You could pick pretty much any place on the polar plateau and it would be fine. We just happened to luck out at how suitable the ice was for certain experiments.
The station is on a moving/shearing ice sheet though, which has some minor implications (like the relative position of the pole changes, so we have to move the marker each year by about 10 m).
I assume you mean located very close to the rotation axis rather than at some other latitude? I think it's convenience, because you can certainly do this at other points close to the pole, but it would involve more slewing I guess and it's mechanically simpler because you don't need to do much field rotation. At the pole, you can practically leave the altitude fixed and only move in azimuth to track something.
There are also telescopes in other places that are fixed in place, they stare at some angle and let the Earth's rotation do the work for surveying.
I'm always amazed at the science we can do. We can measure gravity with satellite constellations so precisely, we can estimate surface features from that. We have ice penetrating radar. We measure glacier velocity. Dive under glaciers.
And yet I'm saddened by the huge waste of it all, as this can be brushed away by one "charismatic" speaker that enough masses will follow. Voters will not want to do anything. People burn their gas stoves out of spite.
When the ice melts we will probably find an remnants of an advanced civilization. Through some of the preserved records we will see that they were trying there best to ban solar and wind and rid the earth of electric cars so as to ward off global cooling.
The lack of ice weight would allow the land to rebound upwards:
https://polarjournal.ch/en/2022/07/13/what-greenland-and-ant...