Dr. Hirose's experiments show that Earth's inner core is a "forest" of such iron crystals, some likely as massive as 10 km long, all pointing toward magnetic north.
This is only one of many amazing advances geolophysicists have made in recent years as they piece together Earth's birth. It's a fascinating story.
An excerpt from my book The Path: Origins:
Consider for a moment the staggering alignment of circumstances that have led to your existence: 13.7 billion years ago – give or take some pocket change – the universe was born in a primal blast of plasmic energy that rocketed outwards with incomprehensible force and speed, expanding trillions upon trillions of times from a single point within the space of 10–32 seconds. At the outset, the universe was so superhot that no stable particles could emerge, and fundamental forces such as gravity and electromagnetism were merged into a single, tremendously powerful unified force, which blasted all of space outward. Gradually the plasma cooled, allowing the separation of the fundamental forces, and the first particles began to form.
The cooling of this great plasma cloud allowed the formation of particles such as those which make up our present-day universe, primarily the simplest of elements, hydrogen. Over billions of years, giant molecular clouds of superhot gases called stellar nurseries would give birth to successive generations of supermassive primeval stars. Hot gases and stardust ejected from these blazing primeval stars clustered in great swirling clouds, forming galaxies and planets.
The Milky Way Galaxy is among them, 100,000 light years in diameter and about 1,000 light years thick on average, containing somewhere on the order of 100 billion stars, with possibly 300 billion more tiny dwarf stars we are not yet able to detect. At its core, a light-devouring supermassive black hole seems to lurk, some four and a half million times the mass of our Sun.
The Solar System itself lies on the edge of the galaxy’s spiral Orion arm, some two-thirds of the way out from the core. It formed 4.6 billion years ago, as a region of molecular cloud underwent gravitational collapse. Gravity, pressure, rotation and magnetic fields flattened and contracted its mass, creating a dense, hot protostar at its core. This core condensed and grew even hotter, causing hydrogen atoms to fuse together, giving birth to our Sun, while the outer reaches of the disk cooled and condensed into mineral grains. Dust and grains collided and clumped, growing ever-larger – forming chondrules, meteoroids, planetesimals, protoplanets and finally planets, as gravitational attraction swept up additional fragments encircling the Sun. About a third of the age of the universe itself, Earth was born some 4.54 billion years ago, and now once every 365 days faithfully orbits that tremendous ball of blazing hydrogen and helium 93 million miles away. Just 100 million years after its initial formation, the infant Earth was smashed by another planetary body, knocking off a massive chunk to be trapped in eternal orbit as our Moon.
Our home is a rather unlikely object – a massive, spinning sphere of liquid, rock, metal and gas, fluid layers and plates, all held in delicate suspension within a great void by the invisible, binding force of gravity. Deep under the crust, molten metal sloshes around a solid iron-nickel core, creating a geodynamo - a planet-enveloping magnetic field which deflects most of the the sun’s solar wind, thus preventing it from blasting our atmosphere into space. It’s the interplay between this solar wind and our atmosphere that creates the breathtaking night-sky light show known as the Aurora Borealis or the Northern Lights.
Some nine billion years after the universe’s explosive birth, the first forms of life began to swim about this watery, star-born mass of rock. A very precise sequence of events occurred, allowing these fragile organisms to gradually grow in ever-greater complexity, to the point where they became self-aware, able for the first time to stare into the vast, cold reaches of the cosmos and wonder what miracle begat them.
Sources: The Path: Origins, copyright 2014, Eric A. Smith, Polyglot Studios
"Earth's core far hotter than thought", April 26, 2013, Jason Palmer, BBC News
Video: "What is at the centre of the Earth?" August 31, 2011, BBC News
(Earth's surface is 71% water, nearly of it [97.5%] salt water. The crust is just 50 km thick on average; below that is a mantle, 2,900 km thick . Still deeper is a sea of molten metal some 2266 km deep, sloshing about at a scorching 4000-5700 degrees C. The core is solid iron-nickel crystals some 1200 km in radius, at temperatures found on the surface of the sun - 6000 degrees Celsius [10,832 F]).