I have some questions about Uranus. From JPL's website it says that Uranus has no solid surface, however later on they say the following: <font color="yellow"> The bulk (80 per-cent or more) of the mass of Uranus is contained in an extended liquid core consisting primarily of 'icy' materials (water, methane, and ammonia), with higher-density material at depth. </font><br /><br />So what does this mean exactly? This means its not completely solid, so what would an 80% material be like? Like a thick, muddy substance?<br /><br />My next question would be since Uranus is titled on its side, if there were a solid surface that an astronaut could land on and walk on, would there be any difference walking on the surface then it is walking on a planet that is not on its side or would the astronaut not be able to tell a difference?