sqizee - Thank you for inviting questions about Neptune. You have zeroed in on rotational plane and axis. <br /><br />The origin of Neptune and Uranus, plus their subsequent histories, had effects on this and other properties.<br /><br />My question to you is:<br /><br />Why is Neptune of higher mean density than Uranus?<br /><br />Why is Neptune's radiation of heat so different from Uranus? Neptune, like Saturn and Jupiter, emits about twice as much heat as it receives from the sun.<br /><br />However, as of 1991, no internal heat source, or evidence thereof, had been found on Uranus.<br /><br />This is from "The World of Science," volume 7, p. 34.<br /><br />Does this lack of an internal heat source on Uranus have some connection to its unique rotational axis?