Iron vapours help understand formation of Earth, moon

Scientists at the University of California, Davis, are recreating the violent collisions of early Earth. In doing so, researchers have been able to study the behavior of vaporized iron -- gaining a better understanding of the formation of the Earth and the moon.
UC Davis scientists were assisted by researchers at the Lawrence Livermore National Laboratory, Sandia National Laboratory and Harvard University. To recreate the conditions of the early solar system, scientists used Sandia National Laboratory's Z-machine, largest X-ray generator in the world. More specifically, scientists slammed aluminum plates into iron samples at high speed, mimicking the condition of early Earth impacts and collisions.
The experiments proved that the pressures necessary for iron to vaporize aren't as intense as previously suspected. This mean more iron was likely spewed skyward than melted back into inner Earth.
"Rather than the iron in the colliding objects sinking down directly to the Earth's growing core, the iron is vaporized and spread over the surface within a vapor plume," lead study author Richard Kraus, research scientist at Lawrence Livermore National Laboratory, explained in a press release. "This means that the iron can mix much more easily with Earth's mantle."
Scientists theorize the vaporized iron would have fallen back to Earth in the form of iron rain, mixing with Earth's still-molten mantle. The revelation also explains why the moon is mostly iron free, as its low gravity wouldn't have been able to pull back its vaporized iron -- the misty metal likely lost to larger planets like Earth.
The study was published this week in the journal Nature Geoscience.
Source: UPI