Friday, December 19, 2003

Science Friday

Actually I was really looking forward to a little Friday Cat Blogging and had the perfect photo of "Yoda" all prepared. Unfortunately I'm a computer troglodyte and so I gave up trying to figure out uploading and posting a picture before I crash blogger. Again. Sooo, as a very close second I'll honor Kos' Science Friday with one of my favorite obscure science subjects, polar shift:

The North and South Poles have not always been in their present locations. Several theories have been offered to explain observed and suspected movements of the poles in relation to the surface of the Earth. Plate tectonics, the prevailing theory, suggests gradual movements of the surface of the Earth. This theory has been called into question by recent measurements of relative movements of the earth's surface, and by accumulating seismological data. Alternative theories include: Axial shifts; polar wander; and a catastrophic form of polar wander known as Earth crust displacement.

Earth crust displacement?

"An earth crust displacement, as the words suggest, is a movement of the ENTIRE outer shell of the earth over its inner layers. If you remove the peel from an orange and then reattach it to the fruit you can visualize the possibility of the peel moving over the inner layers. The earth's crust, according to Charles Hapgood, can similarly change its position over the inner layers. When it does the globe experiences climatic change. The climatic zones (polar, temperate and tropical) remain the same because the sun still shines on the earth from the same angle in the sky. From the perspective of people on the earth at the time, it appears as the sky is falling. In reality it is the earth's crust shifting to another location. Some land moves toward the tropics. Others shift, with the same movement, toward the poles. Yet others may escape such great changes in latitude."

"Working on the assumption that the earth's magnetic poles are usually close to the poles of rotation, Hapgood collected geomagnetic rock samples, finding evidence that the most recent earth crust displacement must have occurred between 17,000 to 12,000 years ago. The North Pole would have moved from the Hudson Bay area of northern Canada to it's current place in the Arctic Ocean. More recently, Langway and Hansen (1973) gathered climactic data pointing to a dramatic change in climate at 12,000 years ago. At that time, the Pleistocene extinctions, rising ocean levels, the close of the ice age, and the origins of agriculture all seem to coincide."

Simply stated imagine the earth as a giant gyroscope. As ice builds up in the polar regions weight is moved from the equator to the poles. Try this with a gyroscope at home and see what happens. Not a pretty site. Anyway, this weight displacement theoretically reaches a critical point whereas the outer crust of the planet shifts slightly bringing the ice caps into warmer regions (where they immediately begin melting) and regions that were warmer into newly created polar regions where the ice can begin to reform. Hence we have a region of Siberia where there's been hundreds of thousands of warm climate animals found frozen whole and ancient maps of Antarctica showing an exposed coastal line that only satellite radar imaging can find today.

Silver lining? I don't think we have to worry about excessive polar ice building up this time around.