The Sun's raduis.
The Earth's radius.
The radius of the Earth's orbit.
The radius of the solar system.
The distance to the nearest star(excluding the Sun).
Almost perfect circles.
With the Sun at their centers.
Are almost parallel to one another(like sheets of paper on top of each other).
All of about the same radius, 1AU.
Suggestive of a common initial "origin"(or starting point) in the distant past.
The Sun is by far the most massive object in the solar system.
The force of gravity attracts the planets towards the Sun.
Planets are moving quickly(like NASA satellites that circle the Earth).
All of the above.
None of the above.
The orbit semi-major axis (in AU)
The orbit major axis (in AU)
The orbit semi-minor (in AU)
The orbit minor axis (in AU)
The time for one complete rotation of the planet(on its axis).
The time for one complete revolution of the planet around the Sun.
The ratio of the time for one complete rotation of the planet(on its axis) to the time for one complete rotation of the Earth on its axis.
The ratio of the time for one complete revolution of the planet around the Sun to the time for one complete revolution of the Earth around the Sun.
None of the above.
The size of the planet and an average density based on the expected composition(of the planet).
The size of the planet and the (universal) density of water.
Newton's laws of motion and gravity, combined ith the (orbital) period of the planet.
Newton's laws of motion and gravity, combined with the rotational period of the planet.
Newton's laws of motion and gravity, combined with the motion of the planet's moons (that orbit the planet).
Mercury, Earth, Mars, Jupiter
Venus, Mars, Neptune, Uranus
Earth, Mars, Saturn, Neptune
Mercury, Venus, Mars, Saturn
Jupiter, Saturn, Uranus, Neptune
Kuiper belt objects
Ort cloud (objects)
The comet cloud (objects)
An average density greater than water.
Substantial oxygen in its atmosphere and liquid water on its surface.
A changing visual appearence as seen from space.
Fewer moons than Mercury.
Fewer moons than Venus.
Fewer moons than Jupiter.
More moons than Saturn.
More moons than Uranus.
Lie almost in one plane.
Lie very close to the "ecliptic".
A and C
B and C
Only from an observer in the distant fringes of the solar system.
Never...as the planet orbits are randomly oriented.
Even from Earth...as a near linear alignment of the planets in the sky.
Even from Earth...but only using sophisticated mathematical models.