Re-order the numbers so the events occur in the correct order, with the oldest event as number 2, and the youngest event as number 13. 2. Now at roughly 100% of present-day mass and the asteroid bombardment over, Earth begins cooling and differentiating. As the outer layer of the Earth cools and solidifies, lighter elements and compounds rise to the surface while the denser ones sink to the core 3. The now differentiated ice, gas, and dust of the solar accretion disc conglomerates together into asteroids from gravity 4. "The Big Whack" A Mars-sized protoplanet we call Theia collides with primitive Earth, adding even more energy and mass 5. The Big Bang 6. As the early atmosphere cools, water vapor is eventually cool enough to condense into liquid water, eventually covering the planet in an ocean 7. The debris from the collision of Earth and Theia produce a ring in orbit. This ring eventually coalesces into the Moon, just as Earth coalesced from the solar accretion disc 8. A nebula collapses from the force of gravity. Our Sun is born with a rotating accretion disc made from the remainder of the nebula surrounding it] 9. Asteroids continue colliding into each other, eventually forming large protoplanets. The inner protoplanets, one of which being Earth, are liquid from the immense heat of all the collisions and internal movement 10. As differentiation continues, the lightest elements and compounds outgas in a series of eruptions. These gasses form our early atmosphere 11. Formation of the Milky Way Galaxy from coalescing of early stars and interstellar gas and dust 12. Solar wind, being highly charged material ejected from the sun, pushes lighter elements in the solar accretion disc, such as Hydrogen and Helium, to the outer reaches of the Solar System. Heavier elements such as Iron, Nickel, and Silicon remain close to the Sun 13. Stars made of only Hydrogen and Helium burn out and die in Novae and Supernovae, producing nebulae rich in heavier elements in the process. This cycle repeats several times