We need the Earth to have a magnetic field to keep our atmosphere where we need it to be. Over the last few decades it has become apparent that the field is weakening; this may just be part of a natural variability in the strength of the field but it does highlight the fact that we don't know enough about it.
In order to try to understand the field it is essential that we make a map of it. The European Space Agency has launched three satellites today to map the field. They will hopefully provide some answers about a crucial aspect of the Earth's physics and possibly help to find mineral resources as well.
This mission is part of the ESA's Earth Explorer Programme.
New research on the movement of iron through silicate rocks by Stanford Unversity has the potential to change our view about how the Earth's core formed. Professor Wendy Mao and her team have discovered that iron can percolate through silicate minerals which means that our idea of the mantle and core being distinct bodies from the earliest stage of formation of the planet may be wrong. Instead we can have a model where after our planet aggregated there was a gradual evolution of the internal structure as the materials differentiated by percolation under the influence of gravity.
The implications of this discovery may be that data we get from meteorites may not give us a good control on the bulk composition of the Earth. It seems that we have a lot more to discover about our planet.
There are things we know about the Earth's Core and lots of things that we don't. We have a good idea about it's composition (from meteorites) and about its state of matter (from seismic evidence). Some new research from Spain suggests that there is more to the Core's structure than had been previously thought in that there are two different hemispheres to the Core that are differentiated by the structure of the iron in the core. The data also suggest that the core is moving.
What do you think about the evidence?
BBC News story
