The planet Earth we live on today bears very few traces of its infancy. The 500 million years between Earth's formation around 4.5 billion years ago and 4 billion years ago – the Hadean eon – is almost a geological black hole . Very little survives from that time. A handful of ancient rocks and scattered zircon crystals preserve rare glimpses of newborn Earth , but most of the planet's earliest crust has vanished. Some researchers have put forth that the reason for this is Earth's efficient