Diamonds Are Almost Forever
Zircon crytals are resistant to melting, and provide clues to ancient events. Analysis of zircons containing the Australian diamonds indicate that Earth cooled within 300 million years of formation. Diamonds require enormous pressures to form, needing a thick continental crust. These diamonds indicate that Earth's crust and oceans could be 4.4 billion years old.
There are many mysteries about the planet beneath our feet. How Earth condensed from a gas has long been a mystery. Particles colliding at orbital velocity will not attract each other gravitationally unless those particles have the mass of mountains. One way to start a planet forming would via with a tiny Black Hole with the mass of a mountain.
This week Planetary Society Blog hosts the Carnival Of Space!