How Earth Resembles a Gooey Confection

Ant contributes a link spotted on Neatorama that may upset middle school Earth Science teachers, writing "LiveScience says Earth's simple schematic is not core, mantle, and crust anymore. It is more like the gooey center of a chocolate morsel harboring peanut butter and honey. Inner Earth is far more nuanced than outward appearances would suggest. A new model is proposed in the May 2, 2008, issue of the journal Science."

Comments

Re:They won't even notice

[gomiam]

Well, I guess Dawkins must have changed his standpoint a bit since 2006. I quote:

The origin of life on this planet -- which means the origin of the first self-replicating molecule -- is hard to study, because it (probably) only happened once, 4 billion years ago and under very different conditions from those with which we are familiar. We may never know how it happened. Unlike the ordinary evolutionary events that followed...

Just two years ago he still stated that the origin of life and evolution were different things. Would you be so kind to point me to references of his conflating both to deny the existence (I'd rather say essence, but that's a Cartesian debate for another day) of God?

Re:It CANNOT be THAT different..

[penguinchris]

I didn't read TFA, but I did read the FSA (fine Science article) itself. Also, IAAGGS (I am a geology grad student.)

It is not as simple as LiveScience apparently paints it - the low velocity seismic zones are well-known to geologists and have been explained by theory fairly completely.

Though this isn't what they're talking about, there are different zones of seismic velocity within the layers themselves due to changes in temperature, pressure, and composition of the material, which leads to zones of partial melting. Seismic waves either slow down or disappear completely in liquids, depending on the type of wave, which explains some of these zones.

What this article discusses is not those zones, obviously, but rather the boundary between layers. There are a lot of thoughts on that, too, and it's well known that the boundaries are not so distinct and perfect. For example, mantle plumes (which form hotspots like Hawaii and Yellowstone) have many theories of origin - one of them being that they originate near the core. If this were true, then there would be hot plumes of material reaching all the way through the earth to the core, which obviously would cause irregularities in the layer boundaries - creating zones of partial melting which slow down seismic waves.

What this new article offers is a model of this behavior based on extended sets of data not available before. It's not really telling us anything too new, rather, it's describing and confirming what was already theorized using some nice new data (which is of course equally important as coming up with totally new ideas, but not as glamorous.)

Now, I'm not sure if anyone actually believed that they do, but geologists do not subscribe to the "middle school" model of earth. And middle school teaching will not change. The concentric sphere model is still fine as a simplification.