AGES AGO Analyses of crystals in rocks in Australia, left, have formed a new picture of the early Earth, depicted with young oceans in the painting at right.

The first 700 million years of Earth’s 4.5-billion-year existence are known as the Hadean period, after Hades, or, to shed the ancient Greek name, Hell.

That name seemed to fit with the common perception that the young Earth was a hot, dry, desolate landscape interspersed with seas of magma and inhospitable for life. Even if some organism had somehow popped into existence, the old story went, surely it would soon have been extinguished in the firestorm of one of the giant meteorites that slammed into the Earth when the young solar system was still crowded with debris.

That is no longer thought to be true.