I was just looking at a globe, and a few things appeared to be strange about the earth:
(1) The North Pole is an ocean , surrounded by landmasses
(2)the Soth Pole is a continent surrounded by oceans
(3) the main axis of the northern-hemisphere land masses are east and west, in the southern hemisphere, the main axix of the continents is north and south
(4) the main river systems of the NH run north and south, in the SH, the rivers run east-west
Now, when the ancient supercontinent (pangea) broke up, millions of years ago, the continents migrated around to their present positions…so why do we have this rather odd 9to my mind) assymmetry of the globe?
Anybody care to comment?
To answer the first part of the question, the Earth certainly is asymmetric. Aside from the bulge in the middle, the majority of the dry land is certainly in the northern hemisphere. As for why, no idea, sorry.
Anyone care to Comment: Sure!
The earth is actually pear shaped and not a perfect sphere as we would all like to beleive. Looking at my pristine globe I wonder why not make the Earth look the way it should in scale?
Well gravity plays the key role in this conundrum. The earth is of course a watery planet, and on a veritable tilt to the sun depending on what season we are in, it is either closer or further tilted to the sun, and this vary’s with the hemisphere you are in. the Gravity of the sun and the moon reletive to how close we are to either plays a key role as well. Factor in the ‘Wobble’ and you get a non spherical planet, shaped more like a Pear.
Is Phlosphr a troll or an idiot?
** Desmostylus** … ???
Check here
OR
Look at Professer Ivan King - University California Berkeley - research on Ellipsoidal and Orthometric Heights and Geoid Models.
Not a troll either … Welcome to the Boards ** Desmostylus **.
Apologies Phlosphr.
Desmostylus ???
“I think it is called Desmostylus, and it’s an ancient sea cow that’s no longer alive. It’s an extinct species.” 
Nice name, welcome to SDMB.
- and 2) are simply the realization of the only two possibilities, land or sea.
- If north america is wider east west than north south, it’s not by much. Australia doesn’t fit the pattern either.
- Rivers have got to pick one direction or the other to flow on each landmass. They can’t very well cross each other can they ?
I think you’ve probably just demonstrated how we instinctively look for patterns, and how readily we find them even when they aren’t there. No doubt the trait has survival benefits, but that’s way off topic.
This is another example of what I call “viewpoint bias.” People see things at a given point in time and don’t remember how meaningless that random glimpse actually is.
The continents may have migrated to this position today, but they will be in a different position tomorrow.
Find a site or book that shows the movement of the continents over the history of the Earth or projects it over the next several hundred million years. You’ll find that some or all of your assertions about the earth no longer apply.
There is actually no reason to ever expect a truly symmetrical positioning of oceans and land masses on a surface that is constantly in motion in random directions. I’d be surprised if this has ever happened in earth’s history. Asymmetry is natural and normal.
The equitorial bulge of the earth resulting from rotation is 13 miles high. So the equitorial diameter is 26 miles greater than the polar diameter. If the earth were reduced to the size of a ping-pong ball this would amount to just a little over a 0.003" difference. I don’t think most ping pong balls are round to that accuracy.
For a one foot globe the difference would be about 0.039" or 1 mm.
The southern hemisphere is sliightly bulgier than the northern and the south pole is slightly closer to the geometric center than is the north pole. But the differences are in the 100’s of feet range.
To the eye, the earth is a perfect sphere so our globes are accurate.
Let’s make that “equatorial” in all cases, shall we? And I had to wait to post this because the administrator has specified that only one post every 60 sec. is permitted.
True. But the Earth is actually rounder than your “pristine globe”. Even a highly-polished billiard ball is less round and has deeper hills and valleys (to scale) than the Earth.
Leaving aside the why, the fact that the northern hemisphere land extends largely E/W, while the southern hemisphere ismainly N/S has had important economic and political consequences. See Guns, Germs, and Steel by Jared Diamond. Basically with an E/W orientation, you can agricultural developments in one area spread all over, while in the other direction, any innovations are likely to be very limited because the climate changes so rapidly.
Well, not really pear shaped. According to this abstract of an article by our own RM Mentock, the Earth’s alleged pear shape was based on incomplete data, and “The Earth should no longer be said to be pear-shaped.”
Based on his posting history RM Mentock probably missed this thread. I see he’s posting again, so he’ll probably catch this thread now.
Slight hijack.
In the Desert Museum, just outside of Tucson, Arizona, there is a stone globe, about 3 feet in diameter.
It is claimed to be a microscopically accurate duplicate of Earth (I don’t remember to what accuracy.)
If you run your hands over the globe, you don’t notice any irregularities, it’s as smooth as fingers can detect.
probably everyone rubbed the mountains off feeling them… just kidding…
Seriously, that would pretty cool, I’d like to see that globe.
Well, IIRC, long ago, people believed that the earth was symmetric, so there would be a southern Asia as well as a Northern Asia, so to speak, as a counterbalance. The name Austraila comes from the concept Terra Austrailus, or “The Great Southern Continent”.
And that, my liege, is how we know the earth to be banana-
shaped.
And more like 10’s of feet range, if not less, in that case.
Yep, it’s more tetrahedral, at degree three. The “pear” and the “rounded-off tetrahedron” are degree-three spherical harmonics, but even though the tetrahedral shape is a lot stronger than the pear-shape, it is a few magnitudes smaller than that centrifictional bulge mentioned earlier–and even that bulge would be hardly noticeable on a globe.
On my six, thanks 
Why would you like to see that globe? He just said you don’t notice any irregularities… It’s just like any sphere globe.
When I was in school they told me it was because of all the ice on the polar ice cap in Antarctica. It sounded then, and still sounds, awfully improbable. Anyone know anything about that?