earth's orbit about sun

I underdstand the earth's orbit is elliptical, almost circular and the
sun is at one of the focal points. I also know that the earth's axis
is tilted in realtion to our plane of orbit about the sun (the
ecliptic), and that this axial rotation also precesses. Also i've
found that the planes of orbits of the planets are close to being the
same plane, but they are not actually in the same plane.
What I have not been able to determine is whether the sun is actually
on the plane that the earth's orbit defines.
to give a visual: say I'm stadning on a mountian top, representing the
sun, and a helocopter representing the earth is flying around me. Will
the helicopters orbit be at the same elevation as I am around its
entire path? Or would its entire path be the same elevation but at a
higher altitude (or lower) than I am? Or would it always be higher
when it is in one spot and lower 180degrees from that spot, but not be
axial centerd on my mountain top, or in the same plane? And if so then
how is that oriented with respect to the tilt of the earth's axis (at
this current time/epoch)?

i found the foloiwng link which presents a picture that shows a
deviation like I am asking about but it does not provide any
explanation and is left me with vagueness and questions.

http://www.polaris.iastate.edu/North...unit3_sub1.htm

wrote in message oups.com...
I underdstand the earth's orbit is elliptical, almost circular and the
sun is at one of the focal points. I also know that the earth's axis
is tilted in realtion to our plane of orbit about the sun (the
ecliptic), and that this axial rotation also precesses. Also i've
found that the planes of orbits of the planets are close to being the
same plane, but they are not actually in the same plane.
What I have not been able to determine is whether the sun is actually
on the plane that the earth's orbit defines.
to give a visual: say I'm stadning on a mountian top, representing the
sun, and a helocopter representing the earth is flying around me. Will
the helicopters orbit be at the same elevation as I am around its
entire path? Or would its entire path be the same elevation but at a
higher altitude (or lower) than I am? Or would it always be higher
when it is in one spot and lower 180degrees from that spot, but not be
axial centerd on my mountain top, or in the same plane? And if so then
how is that oriented with respect to the tilt of the earth's axis (at
this current time/epoch)?

The Sun is in the plane of the Earth's orbit.

The focus of an ellipse is in the plane that the
ellipse is in.

wrote:
I underdstand the earth's orbit is elliptical, almost circular and the
sun is at one of the focal points. I also know that the earth's axis
is tilted in realtion to our plane of orbit about the sun (the
ecliptic), and that this axial rotation also precesses. Also i've
found that the planes of orbits of the planets are close to being the
same plane, but they are not actually in the same plane.
What I have not been able to determine is whether the sun is actually
on the plane that the earth's orbit defines.
to give a visual: say I'm stadning on a mountian top, representing the
sun, and a helocopter representing the earth is flying around me. Will
the helicopters orbit be at the same elevation as I am around its
entire path? Or would its entire path be the same elevation but at a
higher altitude (or lower) than I am? Or would it always be higher
when it is in one spot and lower 180degrees from that spot, but not be
axial centerd on my mountain top, or in the same plane? And if so then
how is that oriented with respect to the tilt of the earth's axis (at
this current time/epoch)?

and then:

i found the foloiwng link which presents a picture that shows a
deviation like I am asking about but it does not provide any
explanation and is left me with vagueness and questions.

http://www.polaris.iastate.edu/North...unit3_sub1.htm

Ahhh ... it's not clear from the description, but the diagram is shown
from the point of view of someone looking down on the earth's orbital
plane. That 1 degree angle is roughly how far the earth travels in its
orbit in one day.

Greg Neill's answer was correct: the sun *must* lie in the earth's
orbital plane. More technically, the orbital plane is defined by the
center of the sun and the center of mass of the earth and moon (a point
which lies inside the earth, about 3/4 of the way toward the moon).
So the center of the earth doesn't usually lie in the plane of its own
orbit, as the moon's orbit is inclined some 5 degrees to the ecliptic.

Hope this helps.

-- Bill Owen

" wrote in
oups.com:

I underdstand the earth's orbit is elliptical, almost circular and the
sun is at one of the focal points. I also know that the earth's axis
is tilted in realtion to our plane of orbit about the sun (the
ecliptic), and that this axial rotation also precesses. Also i've
found that the planes of orbits of the planets are close to being the
same plane, but they are not actually in the same plane.
What I have not been able to determine is whether the sun is actually
on the plane that the earth's orbit defines.

The Sun is indeed on the plane of the Earths orbit. The solar system
barycenter is always very close to the Sun. This is because the Sun has the
vast majority of the mass of the solar system.

Klazmon.