[X] My Assistant

[JRehling]

Probably some perfect "grand tour" type alignment, where each spacecraft-planet encounter is as close-in to the planet as possible for a departure trajectory that's approximately tangent to the planet's orbit or as close to tangent as possible.

Eris is also well off of the ecliptic at present (and for a long time coming). I doubt that keeping things in the ecliptic for three flybys then counting on Neptune to provide all of the work to acquire a high inclination is feasible. Maybe a Jupiter-Saturn combo could do it, assuming the rings weren't a problem.

That would actually be a scenario that would unfold fairly often.

Uranus is actually in a pretty good position right now for an assist to Eris, but it'll soon move out of that good position and not come back for 8 decades. Neptune, however, is moving into position, but again, Neptune can't bend the path down in very good proportion to Jupiter's bending it out.

In only 230 years or so, Eris will come within 40 AU of the Sun. Let's plan on an Eris Orbiter/Lander then. Start the buzz now.

[Alan Stern]

You probably already know about The Great Planet Debate meeting coming this week near DC, if not, see:
gpd.jhuapl.edu.

To register for Great Planet Debate conference web participation, click: http://tinyurl.com/6xcqec
Watch the talks and debate on line!

-Alan

[Floyd]

JRehling It is clear that you don't like the IAU telling everyone (public, educators) that their definition is a new "Scientific truth". I think most people on this forum would agree. Its just a definition which is neither true or false, but rather useful or not or esthetic or not—most would agree that IAU's definition is not great, or we would not be having this discussion. However, at times you seem to imply that arrogant scientists are to blame for confusing the public. I don't think this is the case. I think we should allow the possibility of a disconnect of the general definition of a word from the definition most useful to a scientific discipline. Do you agree that scientist should be free to give very specific definition of words for their specialty as long as they don't put out press releases stating that a simple definition is a "TRUTH". I sort of like the very old definition of a planet as anything that wonders relative the distant stars. Children and the public should be made aware of the fact that there are often multiple definitions--I agree that "right answeres" should generally have more qualifications.
Floyd

[JRehling]

I'd be happy if this were a situation where a term had a scientific use and a folk use, and never the two did meet. A wonderful example of that is "work", which has a definition in physics and a definition in ordinary life which is quite different. (Except when a laborer hauls things up a hill, and activity which meets both definitions.) Hopefully, no one was ever lectured that their job wasn't work because it failed to meet the physics definition.

However, this "planet" definition has no apparent scientific use, and is being used to *replace* the way the term was previously used. So it's a total strike-out. It doesn't help science, and it does impact the folk audience (kids, laypeople).

And while I agree that a very astute audience (graduate students in the history and philosophy of science) could really sink their teeth into these distinctions, the books I've bought for my son are aimed at an audience that is struggling to understand how a space rock could create a hole in the surface of a planet. Meta-classification is way too abstruse a subject for them. So the discussion doesn't enrich their education. It replaces a small part of it with static. The same way that replacing a small portion of a kid's book about a small country with a paragraph about their bicameral legislature would be static.