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.
Regardless, it's just an interesting snapshot in time considering continental drift.