"JanPB" <filmart@gmail.com> wrote in message 
news:1141781287.963100.256090@z34g2000cwc.googlegroups.com...
> guskz@hotmail.com wrote:
>> I forgot if we know why the earth's forms an elliptical orbit with the
>> Sun, anyone remember?
>>
>> If so then why is it ellipitcal with the Sun at one focal point instead
>> of circular??
>
> Because an orbit has to be a conic section.

That's like saying a hand has to have five digits.
The fact that it does is unrelated to the cause.

> So a closed orbit must be
> an ellipse.

Why closed? Isn't it still an orbit if its a conic section?

> Circle is a special case of an ellipse, so generically a
> closed orbit will be elliptical.

Parabola is another special case of an ellipse.
What's so special about integers zero and one?
What wrong with eccentricity 0.5 is a special case of an ellipse?

The only thing "special" about a circle is that we give it a special name,
its still an ellipse. Of course they don't actually exist in Nature,
every orbit has a non-zero eccenticity. Like your "special" relativity.
It doesn't exist either.

> The planet would have to get somehow
> "initialised" on its orbit *just* right in order to move along a
> perfectly circular orbit.

That's right, and for light to be exactly c in all "inertial" frames of
reference (a "special" FoR like a circle is a special ellipse)  it would
have to get somehow "initialised" on its path *just* right in order
to move along a perfectly straight line.

You are a "special" kind of human being. A fucking moron.
Androcles.