Scientists have used meteorites from Mars and other planetary
bodies to help resolve how the Earth's core formed. Comparing
meteorites provided by the Natural History Museum, with
terrestrial rocks, scientists discovered that the Earth's
metallic iron core, the area that gives the Earth its magnetic
field, is very likely to contain small amounts of silicon.
Silicon is the major constituent of the silicate minerals and
rocks that build the Earth's crust and underlying mantle.
However, there has been no direct evidence that light elements,
such as silicon, exist in the Earth's core since the idea was
proposed by Harvard geophysicist Francis Birch in 1952. The
international team, lead by Alex Halliday from Oxford
University, applied novel analytical techniques and compared the
abundance of isotopes of the element silicon in meteorites with
those in rocks from Earth. Isotopes are atoms of the same
element that differ slightly in mass. These small mass
differences can be analysed using sophisticated mass-spectrome