How a vaporized Earth might have cooked up the moon

The moon might have formed from the filling during Earth’s jelly doughnut phase.

Around 4.5 billion years ago, something hit Earth, and the moon appeared shortly after. A new simulation of how the moon formed suggests it took shape in the midst of a hot cloud of rotating rock and vapor, which (in theory) forms when big planetary objects smash into each other at high speeds and energies.