Balanced
For those suffering from the cold, this idea would have its appeal: the globe would tip over and Germany would suddenly be in the tropics. Bad sci-fi? Not necessarily - maybe even active Earth history.
Carousel and car drivers know the phenomenon well enough: In the bend, it carries you outwards, and the faster the bend is taken, the stronger the centrifugal forces become. Often enough in these situations, for example, a poorly loaded delivery van tips over because the center of gravity of the load was too high and the centrifugal forces that keep the vehicle on track exceeded the centrifugal forces.
Of course, the driver is usually responsible for this himself, but what does a planet do that is racing around the sun at more than 100,000 kilometers per hour on an elliptical orbit if it suddenly has an imbalance - for example because the heavy continents gather at the pole? Does it throw him off the curve? Does he faint? Science has been dealing with these exciting questions for almost 140 years; Adam Maloof of Princeton University and his colleagues may now have the first answers.
They dug 800-million-year-old sedimentary rocks from the seabed near Svalbard with a striking interior. Currently, when iron-fiber-bearing sediments sink to the bottom of the North Atlantic, the metallic fragments are oriented toward the Canadian Arctic Islands, where the magnetic north pole is currently located. This adjustment changes with the moving magnetic pole and can also change completely in the opposite direction if the corresponding south and north poles swap positions. All these changes in the earth's magnetic field are therefore reflected in the corresponding receptive rocks.
But the magnetic particles in Maloof's samples showed a very peculiar signature that, together with the results of geochemical investigations, could not be reconciled with the current theories of geomagnetism or plate tectonics: Their orientation changed in a geologically short time twice by more than fifty degrees, which would have been too violent for a phased reversal of the two magnetic poles.
The scientists quickly ruled out various possible explanations. For example, they did not consider a rapid rotation of the tectonic plate and Svalbard to be plausible - especially since the sedimentation around the islands would have had to stop at the same time in order to tear the gap between the two orientations. Instead, Maloof and his team unearthed an old theory that keeps haunting the research landscape - and so far unproven - that the world is tilting. The position of the earth's axis, around which it rotates, remains largely stable relative to the sun and thus the geographic North Pole also in the north. The earth, however, rebalances the unequally distributed weights on its surface or in its interior by removing them from the endpoints of the axis.
About 800 million years ago, the earth probably rotated through space with just such a considerable imbalance at the North Pole, because a gigantic volcano might have formed there and shifted its center of gravity. The centrifugal forces tugging at our planet during its space flight around the sun were not sufficient to throw the earth out of its orbit. However, they were still strong enough to eventually cause them to tip over and thus shift the disturbing weight towards the equator - a kind of real polar migration, which caused the geomagnetic north pole to also slip into this region and thus orient the iron particles in this direction.
This process did not happen overnight, but on geological time scales it was extremely rapid. At a speed of several meters per year, the continents, which are comparatively stable on the globe, changed their position in relation to the earth's axis ten to a hundred times as quickly as with a common geotectonic plate movement just because of the tilting movement. After only five to twenty million years, arctic areas were in tropical areas and vice versa - for comparison: since the separation of Africa and South America, about 140 million years have passed before they took their current position.
This polar migration would also explain strange chemical changes and sea level fluctuations in the oceans that were brought about in other epochs of ice ages. However, there is currently no evidence of a comparable cooling of the earth around 800 million years ago. However, if rivers suddenly dumped their dissolved and solid cargo no longer into the North Sea but into tropical waters, this could leave the corresponding geochemical fingerprints in the sediments, according to the researchers.
In order to substantiate their thesis, they are now looking for other rocks from that turbulent time, which turns out to be rather difficult, since most of them are already weathered. However, Maloof's team wants to take a closer look at promising country outings in Australia. But regardless of whether the polar migration is then confirmed or not, the earth is currently not whizzing through space on a lurching course: the land masses are distributed evenly.
