How were the planets formed? --- Erin, Gilbert, Ariz.
Marshall Brain Answered:
The current thinking is that: 1) A star exploded and created a cloud of dust, 2) gravity started pulling the dust particles together, 3) planets arose from a disk of dust that surrounded the sun, as described here:
But, as the following video discusses, it is not yet completely clear how these particles always stuck together:
Science still has a way to go before the planet-formation process is completely understood.