<blockquote><font class="small">In reply to:</font><hr /><p>By tail, I was referring to comets.<p><hr /></p></p></blockquote><br /><br />Ah. So you meant relatively dense tails.<br /><br />No, that would not be the final nail in the coffin. For one thing, the question of "planet" is largely one of semantics, and there's no objective resolution to a debate like that. Such is the nature of human language.<br /><br />Actually, if it proved to be a comet-like tail, that would be extremely puzzling. Comets do not have tails when they are that far from the Sun, so it would indicate that something unexpected was going on.<br /><br />Incidentally, there is presently no solid evidence for rings or a tail or a dust cloud around Pluto. There is some suggestion that something might be there, but it's within the margin for error so it's hard to make any conclusions from it. Pluto is a very challenging object to study because of its small size and great distance. Regardless of what New Horizons finds in nine years, I can guarantee at least some of it will be unexpected, simply because we know so little about Pluto right now. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em> -- The Tenth Doctor, "Blink"</font></p> </div>