An asteroid is a minor planet â€an object larger than a meteoroid (thus 1 meter or larger) that is neither a planet nor an identified comet â€that orbits within the inner solar system or is co-orbital with jupiter … Nasa’s asteroid trackers have just watched a schoolâ€'busâ€'sized space rock make a safe, distant pass by our planet, part of a steady stream of small objects that routinely zip through the