The solar system that we're familiar with today arose from a solar nebula, a giant, rotating cloud of particles that encircled the young sun in its early days. These particles eventually formed Earth and the rest of its planetary peers. They also were the building blocks for planetoids and other cosmic bodies.
What is the best way to see comets?
Answered by Science Channel
What was NASA's Deep Impact?
Answered by Discovery Channel
What is NASA doing to protect us from asteroid impacts?
Answered by James L. Green