Solar System the orbit of the next nearer object to the Sun. For example, Venus is approximately 0.33 AU farther out from the Sun than Mercury, whereas Saturn is 4.3 AU out from Jupiter, and Neptune lies 10.5 AU out from Uranus. Attempts have been made to determine a relationship between these orbital distances (for example, the Titius–Bode law), but no such theory has been accepted. The images at the beginning of this section show the orbits of the various constituents of the Solar System on different scales. Some Solar System models attempt to convey the relative scales involved in the Solar
Centaur (minor planet) evolve into Jupiter-crossing orbits whereupon their perihelia may become reduced into the inner Solar System and they may be reclassified as active comets in the Jupiter family if they display cometary activity. Centaurs will thus ultimately collide with the Sun or a planet or else they may be ejected into interstellar space after a close approach to one of the planets, particularly Jupiter. The relatively small size of centaurs precludes remote observation of surfaces, but colour indices and spectra can provide clues about surface composition and insight into the origin of the bodies. The colours of centaurs are very diverse,