Article: <[email protected]>
From: [email protected](Nancy )
Subject: Re: 12th Planet - any photos ?
Date: 27 Feb 1997 02:40:39 GMT
In article <[email protected]> Lamont
Granquist writes:
> Any function of time giving r.a., dec. and distance would
> suffice. Even piecewise approximations to the orbit at
different
> epochs would be totally acceptable. This is exactly what is
> done with the ephemerides, although, feel free to use
functions
> more complicated than an ellipse. All you have to do is
> get it accurate to within a couple of arcminites and also
> have an accurate proper motion for it (so we know how
> fast it should be moving across the field of view) and we
> can work with that...
> [email protected]
How about a flapping, bobbing bird? Remember all that discussion on sci.astro about retrograde orbits? The 12th is coming straight at us BUT, moves first into a regular orbit around the Sun with the other planets, moves up toward the ecliptic plane for the same reasons the other planets are there, and then starts into its retrograde orbit and finally plunges well below the elliptic in the weeks ahead of its roaring through the Solar System. Bottom line, your usual calculations won't predict where it will be - you HAVE no formulas for this guy's path.
(Begin ZetaTalk[TM])
ZetaTalk: Retrograde Orbit
As we have mentioned, the 12th Planet's approach at this time, as viewed from Earth, has it essentially standing still. Just as the appearance of the flight of a bird might have it bobbling up or down a bit in flight, as it approaches the observer, if viewed from above the flight the path would appear straight, and if viewed from the side where the rapid forward progress of the bird is more dramatic than any bobble up or down due to its beating wings, the path would likewise appear straight. This false illusion of motion when the observer is not at an angle that presents the true motion of the object being viewed is especially true if the observer is also in motion. If the observer is running toward the bird, rocking to the right and left in his running stride, the bobbling of the bird is compounded by the eyes-view of the human runner so that it appears to be jiggling side to side too.
Astronomers are well aware that the apparent retrograde motion of the outer planets is in fact due to the more rapid orbit of the Earth. Draw a line from the Sun through the Earth and on out to a planet such as Jupiter. Both are revolving around the Sun in a counterclockwise manner as viewed from above the ecliptic, up above the North Pole. Yet due to the faster motion of the Earth, Jupiter would appear to be to the left of the Earth, then to the right, and thus appear to be moving left to right around the Sun, a clockwise motion. Bearing in mind that appearances can be deceiving, and just why that is, the following is what humans can expect to observe as the 12th Planet approaches for its periodic passage.
As we have mentioned, the path the 12th Planet takes between its two foci is like a train track, the path in one direction lined like a straight line next to the path in the other direction. However, this direct path does not hold when the giant nears one of its foci, passes, and turns around on the opposite side for the return trip.
(End ZetaTalk[TM])
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