The mainstream has a strange preference for reporting Geocentric Orbital Inclinations [for the planets within the Solar System] with reference to the Geocentric Ecliptic.
Orbital inclination is the angle between a reference plane and the orbital plane or axis of direction of an object in orbit around another object.
In the Solar System, the inclination of the orbit of a planet is defined as the angle between the plane of the orbit of the planet and the ecliptic.
The ecliptic is the apparent path of the Sun on the celestial sphere, and is the basis for the ecliptic coordinate system.
It also refers to the plane of this path, which is coplanar with both the orbit of the Earth around the Sun and the apparent orbit of the Sun around the Earth.
Accordingly, the Solar Equator has an obliquity of 7.25 degrees to the Geocentric Ecliptic.
Rotational and Orbital parameters Sun Earth Obliquity to ecliptic (deg.) 7.25 23.45
Sun Fact Sheet
Calculating the Heliocentric Orbital Inclination of a planet is simply performed by subtracting the Geocentric Orbital Inclination from 7.25.
However, in accordance with the mainstream convention, the result of the Heliocentric Orbital Inclination calculation is an unsigned absolute number [between 0 and 180].
The inclination of orbits of natural or artificial satellites is measured relative to the equatorial plane of the body they orbit if they do so close enough.
The equatorial plane is the plane perpendicular to the axis of rotation of the central body.
an inclination of 0° means the orbiting body orbits the planet in its equatorial plane, in the same direction as the planet rotates;
an inclination greater than 0° and less than 90° is a prograde orbit.
an inclination greater than 90° and less than 180° is a retrograde orbit.
an inclination of exactly 90° is a polar orbit, in which the spacecraft passes over the north and south poles of the planet; and
an inclination of exactly 180° is a retrograde equatorial orbit.
Plotting the Heliocentric Orbital Inclination clearly indicates that planet Earth [blue dot] is the outlier with an Heliocentric Orbital Inclination of 7.25 degrees.
The plot also suggests that Ceres should be regarded as a planet and that it should not be ignored [nor excluded] because the mainstream have designated it a dwarf planet.
Ceres (minor-planet designation: 1 Ceres) is the largest object in the asteroid belt, which lies between the orbits of Mars and Jupiter.
It is composed of rock and ice, is 950 kilometers (590 miles) in diameter, and comprises approximately one third of the mass of the asteroid belt.
It is the only dwarf planet in the inner Solar System and the only object in the asteroid belt known to be unambiguously rounded by its own gravity.
The plot of Heliocentric Orbital Inclinations is [intriguingly] reminiscent of the Heliospheric Current Sheet [aka Parker Spiral] and conveys the visual impression that the inner planets are surfing the Parker Spiral [aka Parker Propeller].
The heliospheric current sheet is the surface within the Solar System where the polarity of the Sun’s magnetic field changes from north to south.
This field extends throughout the Sun’s equatorial plane in the heliosphere.
The shape of the current sheet results from the influence of the Sun’s rotating magnetic field on the plasma in the interplanetary medium (Solar Wind).
A small electrical current flows within the sheet, about 10−10 A/m². The thickness of the current sheet is about 10,000 km near the orbit of the Earth.
Solar System – Rankine Vortex