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Geology

The Sun ignites

4.57 billion yrs ago

A cloud of gas collapses — everything else is leftovers

See it on the timeline

In depth

This we can date with unusual precision. The oldest solids in the solar system, calcium–aluminium-rich inclusions in meteorites, are dated to 4.567 billion years with an uncertainty of under a million years — the sharpest number on this entire timeline. The Sun holds 99.8 per cent of the solar system's mass; every planet combined is a rounding error. Our composition comes from earlier stars that exploded: the carbon in your body was made inside a star, the iron in your blood in a supernova.

For children

A huge cloud of gas and dust in space began falling in on its centre. There it grew so dense and hot that a star lit up: our Sun. Everything left over — the planets, the moons, you and me — is just the debris in the ring around it.

Connects to

Part of Terra Saga — the story of Earth on a timeline. terrasaga.org