Existing comment:
A PLANETARY SYSTEM IS BORN
DUST IS CLEARED AS PLANETS FORM: The protoplanetary disk phase ends with the formation of planets and clearing of gas from the disk. Gaps appear in the disk as the planets grow, here illustrated by the giant gas planets (left). After planetary growth ended, the Solar System could have been configured with an outer disk of icy bodies and with Uranus as the outermost giant planet (above, right). Today, Neptune is outermost. |