Originally posted by HarisZXC:if the asteroid is as big as earth, would'nt it be big enough to revolve around the sun due to the sun's gravity and be considered a planet?
That is because the asteroid has a high inertia as well, and since it has been travelling in that single direction at a high speed towards Jupiter, the sun's gravity wasn't strong enough to force it to change its direction completely to the point where it will start revolving around the sun instead.